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Faculty of Engineering and Materials Science
Civil Engineering Program
German University in Cairo
Structural Design and Modelling of
Midrise Reinforced Concrete
Buildings
Bachelor Thesis
Author: Ahmed Wael Mohamed Gondia (22-3786)
Supervisor: Prof. Dr. Nayer El-Esnawy
Submission Date: 3 June, 2014
Faculty of Engineering and Materials Science
Civil Engineering Program
German University in Cairo
Structural Design and Modelling of
Midrise Reinforced Concrete
Buildings
Bachelor Thesis
Author: Ahmed Wael Mohamed Gondia (22-3786)
Supervisor: Prof. Dr. Nayer El-Esnawy
Submission Date: 3 June, 2014
This is to certify that:
(i) The thesis comprises only my original work towards the Bachelor Degree.
(ii) Due acknowledgement has been made in the text to all other material used.
Ahmed Wael Mohamed Gondia
3 June, 2014
Acknowledgements
I would like to express my sincere gratitude to Prof. Dr. Nayer El-Esnawy for his tireless efforts
and unparalleled supervision throughout the duration of the project. Had it not been for his
patience, motivational compliments and friendly approach, I would not have been able to
complete this project in the sense of satisfaction that I have. I have developed as an engineer, and
more importantly, as a person courtesy of his guidance and superb vision. I also owe a great deal
of appreciation to my parents, who have inspired me and pushed me through the toughest of
times with their endless support and unconditional love.
V
Abstract
Midrise reinforced concrete buildings are an integral constituent of the modern urban
environment, and rest assured, their structural implementation is by no means a simple task. A
tremendous burden of responsibility lies on the shoulders of structural engineers, as the room for
error is intolerable, and thus, the main objectives which paved the way for the work done
throughout this bachelor project, were severe precision and attention to detail. The purpose of
this paper is to provide an elaborate explanation for the various processes conducted concerning
the two main parts of the project. The first of these being the development of structural design
spreadsheets using Microsoft Excel, to serve as design tools for the main structural members of
midrise buildings, as columns, slabs and beams, with all their different design cases and
approaches. These spreadsheets follow the instructions and limit states of the Egyptian Code for
Design and Construction of RC Structures (ECP 203) and the Egyptian Code for Load and Force
Calculations (ECP 201). Also presented, are the necessary validity verifications for ensuring the
proper functionality of the spreadsheets and their accuracy in obtaining results.
The second part of the project, as thoroughly discussed within the contents of the thesis, is the
use of the conducted design spreadsheets in the execution of an actual midrise reinforced
concrete building, following the guidelines and requirements of the ECP 203 and ECP 201. The
featured tasks for the successful completion of this branch project include: selecting an adequate
structural system, creating a structural plan, performing preliminary proportioning for the
structural members according to the ECP, acquiring convenient design loads, modelling of floor
plan using a structural analysis software, performing precise structural analysis for the floor plan,
identifying design demands, designing of reinforced concrete structural members and preparing
final structural drawings. Furthermore, quantity estimation and cost analysis investigations have
been conducted for the building, and a final bill of quantities for the used materials has been
extracted.
VI
Contents
Chapter 1 Introduction ............................................................................................................... 1
1.1 Motivation ........................................................................................................................ 4
1.2 Aim of the Project ............................................................................................................ 4
Chapter 2 Background ............................................................................................................... 5
2.1 Essential Aspects of Reinforced Concrete Structures ...................................................... 6
2.1.1 Introduction to Reinforced Concrete ........................................................................ 6
2.1.2 Factors Affecting Concrete Ultimate Strength ......................................................... 7
2.1.3 Types of Design Loads ........................................................................................... 10
2.1.4 Limit States Design Method ................................................................................... 11
2.1.5 Structural Systems .................................................................................................. 12
2.2 Architectural Drawings Versus Structural Drawings ..................................................... 15
2.2.1 Architectural Drawings ........................................................................................... 15
2.2.2 Structural Drawings ................................................................................................ 16
2.2.3 Comparison Between Architectural and Structural Drawings ................................ 17
2.3 Computer-Based Softwares for Structural Purposes ...................................................... 18
2.3.1 SAP2000 for Structural Analysis ............................................................................ 18
2.3.2 Excel Spreadsheets for Structural Design ............................................................... 20
2.3.3 AutoCAD for Structural Drawings ......................................................................... 21
Chapter 3 Structural Design Spreadsheets Using Excel .......................................................... 22
3.1 Format and Style ............................................................................................................ 23
3.2 Design Tools Package 1: Columns................................................................................. 25
VII
3.3 Design Tools Package 2: Slabs and Beams .................................................................... 31
3.4 Verification of Excel Spreadsheet Results ..................................................................... 40
Chapter 4 Design and Detailing of Midrise RC Building ....................................................... 41
4.1 Drawing Architectural Plan ............................................................................................ 42
4.2 Selecting Statical System and Drawing Structural Plan ................................................ 44
4.3 Preliminary Proportioning of Structural Elements ......................................................... 46
4.4 Typical Floor Modelling Using SAP2000 ..................................................................... 49
4.5 Design and Detailing of Structural Elements ................................................................. 51
4.5.1 Design of Columns ................................................................................................. 51
4.5.2 Design of Cores....................................................................................................... 53
4.5.3 Preparing Columns and Axes Drawing ................................................................... 53
4.5.4 Design of Slabs ....................................................................................................... 57
4.5.5 Preparing Slab Reinforcement Drawing ................................................................. 59
4.5.6 Preparing Stairs and Openings Reinforcement Drawing ........................................ 59
4.5.7 Design of Beams ..................................................................................................... 62
4.5.8 Preparing Beam Reinforcement Drawing ............................................................... 65
4.5.9 Design of Raft Foundation ...................................................................................... 67
4.5.10 Preparing Raft Foundation Drawing ....................................................................... 70
4.6 Quantity Estimation and Cost Analysis ......................................................................... 72
Chapter 5 Conclusion .............................................................................................................. 77
References ..................................................................................................................................... 79
Appendix A ................................................................................................................................... 80
Appendix B ................................................................................................................................. 102
VIII
List of Figures
Figure 1.1: Bachelor Project Action Plan ....................................................................................... 3
Figure 2.1: Effect of µ on ultimate capacity (Ghoneim & El-Mihilmy, 2008) ............................... 7
Figure 2.2: Effect of fy on ultimate strength (Ghoneim & El-Mihilmy, 2008) ............................... 8
Figure 2.3: Effect of fcu on ultimate strength (Ghoneim & El-Mihilmy, 2008) ............................. 8
Figure 2.4: Effect of beam depth on ultimate strength (Ghoneim & El-Mihilmy, 2008) ............... 9
Figure 2.5: Effect of beam width on ultimate strength (Ghoneim & El-Mihilmy, 2008)............... 9
Figure 2.6: Soft-story mechanism (Richard, 2009) ...................................................................... 12
Figure 2.7: Frame-wall structure (The Constructor, 2012) ........................................................... 13
Figure 2.8: Tube-in-tube structure (The Constructor, 2012) ........................................................ 14
Figure 2.9: Example of architectural plan (Allison, 2011) ........................................................... 17
Figure 2.10: Example of structural plan (Helal, 2012) ................................................................. 17
Figure 2.11: Example of a 3D SAP2000 model (Computers and Engineering, 2003) ................. 19
Figure 3.1: Typical introduction page for my Excel spreadsheets................................................ 23
Figure 3.2: Unit converter and inputs for design stresses ............................................................. 24
Figure 3.3: My spreadsheet “Columns Classification” used in my midrise building project ....... 30
Figure 3.4: My spreadsheet “Short Columns 1” used in my midrise building project ................. 30
Figure 3.5: My spreadsheet “Slabs” used in my midrise building project .................................... 38
Figure 3.6: My spreadsheet “Beams Designed for Moment” used in midrise building project ... 38
Figure 3.7: My spreadsheet “Check Shear” used in my midrise building project ........................ 39
Figure 3.8: My spreadsheet “Check Torsion” used in my midrise building project ..................... 39
Figure 4.1: Initial Architectural Plan ............................................................................................ 42
IX
Figure 4.2: Project Architectural Plan .......................................................................................... 43
Figure 4.3: Final Structural Plan ................................................................................................... 45
Figure 4.4: Final AutoCAD file before importing to SAP2000.................................................... 49
Figure 4.5: Completed SAP model for typical floor ..................................................................... 50
Figure 4.6: SAP model showing the reactions of columns and cores to the axial forces imposed52
Figure 4.7: Columns and Axes Plan ............................................................................................. 54
Figure 4.8: Columns Reinforcement Table ................................................................................... 55
Figure 4.9: Final Columns and Axes Drawing ............................................................................. 56
Figure 4.10: SAP model showing bending moment contour on slabs in horizontal direction ..... 57
Figure 4.11: Additional SAP model showing values of bending moment for stair system .......... 58
Figure 4.12: Final Slab Reinforcement Drawing .......................................................................... 60
Figure 4.13: Final Stairs and Openings Reinforcement Drawing ................................................. 61
Figure 4.14: SAP model showing values of bending moment on beams ..................................... 62
Figure 4.15: SAP model showing values of shear force on beams ............................................... 63
Figure 4.16: SAP model showing values of torsional moment on beams .................................... 64
Figure 4.17: Beam Reinforcement Table ...................................................................................... 65
Figure 4.18: Final Beam Reinforcement Drawing ........................................................................ 66
Figure 4.19: SAP model showing springs for raft foundation ...................................................... 67
Figure 4.20: SAP model showing concentrated loads on raft to represent the whole building .... 68
Figure 4.21: SAP model showing bending moment contour on raft in horizontal direction ........ 69
Figure 4.22: Final Raft Foundation Drawing ................................................................................ 71
Figure 4.23: Spreadsheet for determining concrete and steel quantities for columns .................. 73
X
List of Tables
Table 3.1: Limits of Slenderness Ratio for Short Columns (ECP 203, 2007) .............................. 26
Table 3.2: Limits of Slenderness Ratio for Long Columns (ECP 203, 2007) .............................. 26
Table 3.3: Values of k for Braced Buildings (ECP 203, 2007) .................................................... 27
Table 3.4: Values of k for Unbraced Buildings (ECP 203, 2007) ................................................ 27
Table 4.1: Reinforcement Ratios for Structural Elements ............................................................ 74
Table 4.2: Bill of Quantities for the Project .................................................................................. 76
1
Chapter 1
Introduction
Midrise reinforced concrete buildings are one of the most commonly used building types, not
only in Egypt, but in many countries worldwide. This emphasizes on their significance to the
structural engineering world. Buildings with elevations as high as 35 meters, or 12 stories, are
considered midrise buildings. These ranges differ, however, from region to region and are
dependent on the surrounding street conditions. Midrise buildings provide a substantial amount
of space considering their established footprint, and are, therefore, a convenient solution to many
housing problems. They are employed in a number of uses as residential apartments, commercial
facilities, as offices and hotels, and even contribute to mixed uses, as of late.
With that being stated, midrise building construction is no easy task for a structural engineer,
where the attention to detail is of severe urgency, as our line of work deals with the lives of
thousands of people. While many structural engineers are capable of implementing a midrise
building project through the conventional methods, it is rare to find an engineer that has done so
in the unique fashion of completing its design processes with absolutely no structural design
tools offered at first, as in the specifications of my project. As a result of this, I had to rely on
independent efforts to primarily develop the resources with which to work, and complete the
process.
In that respect, my project, “Structural Design and Modelling of Midrise Reinforced Concrete
Buildings”, consists of two sections, or two branch projects. The first section requires the
preparing of structural design spreadsheets using Excel, followed by precise verification of their
functionality and accuracy. These spreadsheets are for the design of the structural elements of
midrise reinforced concrete buildings, and follow the guidelines and limit states of the Egyptian
Code for Design and Construction of RC Structures (ECP 203) and the Egyptian Code for Load
and Force Calculations (ECP 201).
2
The second part of the project is concerned with applying these developed spreadsheets in the
modelling and design of an actual 12 story midrise reinforced concrete building. The midrise
building project involved many phases. It started with the architectural drawings, then moved on
to selecting the statical system, performing the modelling of the building, designing and detailing
of the structural members and preparing the final structural drawings, and finally ended with
carrying out quantity estimation and cost analysis studies for the building. Similarly, the project
fulfills the requirements of the ECP 201 and the ECP 203.
This project, as a whole, is extraordinary in its own way, where one of its sections is highly
dependent on the other, and both are of extreme significance from academic and practical
perspectives. The midrise building project not only depends on the accuracy and reliability of the
design spreadsheets project, but also on the precise timing in finishing certain benchmark tasks.
For further elaboration, design spreadsheets for certain elements had to be finalized and verified,
prior to commencing with the design phase of that specific element in the midrise building
project.
For this consideration, flawless time management was required, in order to maneuver the two
tasks of the project simultaneously and successfully. Therefore, a well conducted action plan, or
time schedule, was put together with careful considerations to the time intervals between tasks
that were mutually dependent. Significant attention had to be employed to commit to the action
plan, in order to avoid any unnecessary postponement. The action plan is demonstrated in Figure
1.1.
3
Fig
ure
1.1
: B
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4
1.1 Motivation
I chose this project because it will help me develop my insight as a structural engineer in both
academic and practical fields. The first part of the project, the design spreadsheets task, requires
that I initially perform an in-depth study on the design of different structural members with all
their possible design cases included in the ECP 203, even those I would not face in the design of
my midrise building, and this would benefit me tremendously from an academic point of view.
Furthermore, the second part of my project, the midrise building task, includes all the phases
done by actual engineers in practice to complete a midrise building. I would experience
executing such a project from start to end, where I would conclude by preparing final structural
drawings valid for actual use on the site of a real project. This would serve as a remarkable
practical experience, where at its end I would be qualified to work at a real structural design firm.
Other motivational aspects include the fact that I would perform quantity estimation and cost
analysis studies, as these are of extreme importance to practical work in the construction market.
Also, I would learn the value of proper time management and being responsible for conducting
an effective time schedule, where my project requires very cautious time perception. Moreover, I
would be allowed to form an independent cycle of work, where I would prepare the necessary
design tools and consequently put them to further use through executing another project with
their assistance. Finally, this project would help me enhance my capabilities in dealing with the
different softwares associated with structural engineering work, as SAP200, Excel and AutoCAD.
1.2 Aim of the Project
The aim of this project is to achieve the deliverables of both its branch projects, in terms of
completing them successfully and adequately with regard to the specifications, while gaining a
substantial amount of personal knowledge, feedback and development in the process. The
deliverables of the Excel spreadsheets project include providing finished structural design
spreadsheets following the ECP 203, and qualified for actual use by any engineering firm.
Another requirement is to carry out adequate verification investigations to ensure their integrity
and reliability.
Concerning the midrise building project, its deliverables were to complete all the following tasks
required for its actual implementation: selecting a structural system, creating a structural plan,
preliminary proportioning of structural members as per the ECP, identifying design loads,
modelling of floor plan, structural analysis of floor plan to determine design demands, designing
of reinforced concrete structural members, preparing final structural drawings, conducting
adequate reinforcement detailing and performing quantity estimation and cost analysis studies
(as an optional task). Finally, the main objective of the project, as a whole, is to produce a
reliable, credible and accurate outcome, which can be actually relied on and showcased to any
practical design firm, while developing our perspectives as engineers throughout the project span.
5
Chapter 2
Background
Ahead of commencing with the elaborate interpretation of the different project tasks and phases,
it is essential to provide a thorough background research for aspects related to the scope of the
project itself. In that regard, this chapter is dedicated to the discussion of several topics for
extensive clarification of the atmosphere of any reinforced concrete structural design project.
This research is divided into three main sections. The first section is concerned with some
essential aspects regarding the reinforced concrete material, structures and design loads. The
following section is dedicated to a comparison between two main elements in any structural
design project, the architectural plan, which initiates the project, and the structural plan which is
produced at its end.
Finally, a third section is provided to discuss the computer-based softwares used in any structural
design project, and their exceptional contribution to the phases of structural analysis, design and
detailing. These specific topics were chosen because they are related to the project specifications,
and concern the main aspects that will be dealt with throughout.
6
2.1 Essential Aspects of Reinforced Concrete Structures
This section discusses some fundamental features regarding reinforced concrete structures. It
includes an introduction to the reinforced concrete material and its unique significance, as well
as an analysis regarding concrete ultimate strength capabilities. It also provides information
regarding the several types of design loads imposed on concrete structures, the limit states design
method for concrete design and the types of structural systems for reinforced concrete buildings.
2.1.1 Introduction to Reinforced Concrete
Among all construction materials, reinforced concrete is one of the leading materials on a global
level, and not just in Egypt, where it contributes to the erection of almost any structure. Concrete
alone, despite having high compressive strength features, exhibits a poor tensile strength; of
approximately one-tenth its compressive strength. This poses complications, as concrete
becomes at risk of failure once tension cracks have appeared (Ghoneim & El-Mihilmy, 2008).
Thus, we resort to reinforced concrete which is an alliance between concrete and steel, where the
steel reinforcement is embedded within the concrete to act together as a strong and coherent
resisting material to both compressive and tensile threats. The high compressive strength of
concrete allows it to withstand the applied compression forces to the concrete element, while the
steel resists tensile stresses and can also resist compressive stresses as in columns. Advantages
and disadvantages of reinforced concrete are as follows (Ghoneim & El-Mihilmy, 2008):
Advantages
- It has high compressive and tensile strengths due to concrete and steel working as a unit.
- As long as there is sufficient concrete cover over the steel reinforcement, it is a very good
resistant to fire in comparison to steel elements.
- Concrete and steel have similar thermal expansion coefficients, 5.5x10-6
for concrete and
6.5x10-6
for steel, which results in a good cooperation regarding reacting to temperature
variations.
- It is an economic mixture with relatively cheap components that can be easily found.
- It is requires low costs for maintenance and has a long service life.
- Construction does not require high levels of skilled labor in comparison to steel structures.
- Can be cast in many shapes and forms.
Disadvantages
- For concrete to harden adequately, it must be kept in place by using forms which are
expensive.
- It is difficult to maintain careful control over the placing and curing of concrete, which leads
to lower quality assurance levels if compared to steel.
- Sizes of reinforced concrete members are big, which require careful precautions and
considerations.
7
2.1.2 Factors Affecting Concrete Ultimate Strength
As knowledgeable engineers, it is of great importance to have a thorough understanding of the
reinforced concrete material, and the factors affecting its strength. Thus, it is referred to a
previously conducted experiment on a reinforced concrete beam, to identify the extent of the
effect of several factors on its ultimate capacity. The factors influencing the ultimate strength of
a reinforced concrete beam resisting bending moment are: the reinforcement ratio, , the steel
reinforcement yield strength, fy, the concrete compressive strength, fcu, the beam depth, d, and
the beam width, b (Ghoneim & El-Mihilmy, 2008). After the experiment, the following findings
were concluded:
- The steel reinforcement ratio “”, is directly proportional to the ultimate capacity of the
beam. This means that the beam’s strength increases as we increase the area of steel
reinforcement in the concrete section. Referring to Figure 2.1, it can be interpreted that by
doubling the reinforcement ratio, from 0.5% to 1%, the beam’s strength increases by a
significant 80%.
- Studying Figures 2.2 and 2.3, we can conclude that steel yield strength is of greater influence
on the beam ultimate capacity than concrete compressive strength. By raising the steel yield
strength from 240 N/mm2 to 400 N/mm
2, the ultimate strength is enhanced by approximately
55%. In contrast, increasing the concrete compressive strength from 20 N/mm2 to 40 N/mm
2
has very little effect on the beam capacity.
- Beam depth has a much bigger impact on the beam strength than its width. Figure 2.4
displays that the ultimate capacity of the beam is improved by approximately 300% after
increasing the beam depth from 500 mm to 1000 mm. However, by increasing the beam
width from, 250 mm to 450 mm, the capacity is only enhanced by a mere 10%, as illustrated
in Figure 2.5.
Figure 2.1: Effect of µ on ultimate capacity (Ghoneim & El-Mihilmy, 2008)
8
Figure 2.2: Effect of fy on ultimate strength (Ghoneim & El-Mihilmy, 2008)
Figure 2.3: Effect of fcu on ultimate strength (Ghoneim & El-Mihilmy, 2008)
9
Figure 2.4: Effect of beam depth on ultimate strength (Ghoneim & El-Mihilmy, 2008)
Figure 2.5: Effect of beam width on ultimate strength (Ghoneim & El-Mihilmy, 2008)
10
2.1.3 Types of Design Loads
Structures are subjected to different kinds of loads, and the circumstances of loading vary with
time. The architectural design, used building materials and position of the structure itself all
affect the type, magnitude and cases of loads applied on the structure (Boeing Consulting, 2014).
The main categories of loads that can act on a structure are:
Dead Loads
Dead loads consist of the structure own weight and loads from the floor cover which include
sand, flooring material and floor finishes. The weight of everlasting non-structural elements as
walls, partitions and built in cup-boards also contribute to dead loads. Dead loads are of fixed
magnitude and constant locations for the whole structure lifespan. They can be accurately
calculated using the acknowledged material weights and the determined volumes, from the
dimensions of the drawings (Boeing Consulting, 2014; Ghoneim & El-Mihilmy, 2008).
Live Loads
Live loads represent all moving entities, and are influenced by the supposed purpose of the
structure. For instance, live loads include people and furniture loads in case of buildings, and
vehicle loads in case of bridges. In addition, they are of changeable magnitude and position
depending on the situation of loading. Nonetheless, live loads are required to be placed in a
manner that will give maximum straining actions imposed on the structure, in order to come out
with the safest design (Boeing Consulting, 2014; Ghoneim & El-Mihilmy, 2008).
Lateral Loads
Examples of lateral loads are wind loads, earthquake loads, fluid pressure and soil pressure. It is
useful to point out that wind and earthquake loads pose risks to the rigidity and serviceability of
a structure. Therefore, the structure must be braced and securely fixed to the foundations to
withstand these loads (Boeing Consulting, 2014; Ghoneim & El-Mihilmy, 2008).
Other Loads
There are many other loads acting on a structure, and these loads include snow loads, thermal
loads and settlement loads. First, snow loads are affected by the location and elevation of the
structure site, and are dealt with through altering the shape of the roof, to avoid snow
accumulation. Secondly, thermal loads occur due to the expansion and contraction of building
materials with temperature variations, and this can cause structural deficiencies. A common
solution is to divide the building elements and provide expansion joints to make the structure
physically divided so that it can safely expand. Finally settlement loads occur when sections of
the structure settle at a greater degree than others. Thus, these loads have to be employed
sufficient consideration (Boeing Consulting, 2014).
11
2.1.4 Limit States Design Method
The most important objectives in a design process are safety and reliability, as it deals with
human lives. In that respect, when designing reinforced concrete members, the capability to
which they are designed to is much bigger than the expected loads. This additional consideration
to the design capacity provides a design that is more safe and reliable against unintentional load
surpluses and imprecise construction, and also helps to restrict deflections and cracking
(Ghoneim & El-Mihilmy, 2008).
Limit states design is a method of design of structural elements based on taking into account the
situations that would lead to the structure failing to redeem its intended purposes. Consequently,
a limit state is a condition for the structural element which if exceeded, the element will be
deemed unfit to attain its required objectives. The limit states design obliges the necessity of the
structure to be secure of these three principles:
Ultimate Limit States
The ultimate limit state refers to the collapse of the structural member. To satisfy the ultimate
limit state requirements, both the design load and the resisting stresses need to be adequately
assessed (Ghoneim & El-Mihilmy, 2008).
Serviceability Limit States
If a structural element is designed to satisfy the serviceability limit state requirements, this means
it is reliable to fulfill its everyday functions, while attaining the desirable level of human comfort
in preventing excessive deflections, cracks and floor vibrations (Ghoneim & El-Mihilmy, 2008).
Stability Limit States
The stability limit state concerns progressive failure, which involves the failure of the structure
as a whole. It also refers to the situations that cause instability as buckling and overturning.
(Ghoneim & El-Mihilmy, 2008).
To conclude, it can be said that by fulfilling the limit states design requirements for a structural
member, it can be trusted to resist the worst case scenario of load combinations it could possibly
face during its life span, while maintaining its level of day-to-day functionality.
12
2.1.5 Structural Systems
A structural system is the system of load bearing elements of a structure, and varies according to
the mechanism in which these components collaborate to transfer the imposed loads among them
until reaching the underlying soil. The main role of the structural system is to support the
structure against gravity and lateral loads. It is absolutely crucial that the structure has adequate
strength to resist vertical loads and convenient stiffness to withstand lateral loads. The main
types of structural systems are as follows:
Moment Resisting Frame System
Moment resisting frames, or rigid frames, comprise of columns and beams which are connected
rigidly. They bear lateral loads through generating straining actions as bending moment, shear
force and normal force within the columns, beams and joints.
There are three classes of reinforced concrete moment resisting frames, and they are ordinary
moment frames, intermediate moment frames and special moment frames. Choice of a type of
moment resisting frame relies on the building height and subjected earthquake loads. To
elaborate; ordinary moment frames are assigned to areas of low seismic threats, where special
moment frames are employed to areas with high seismic activity (Richard, 2009).
Furthermore, the two main types of failure in reinforced concrete moment resisting frames are
the soft-story mechanism and the confinement failure. The soft-story mechanism, as shown in
Figure 2.6, occurs when the building drifts with reference to a single story only, which is usually
the ground floor. Confinement failure however, occurs as a result of structural members being
under confined or over confined (Richard, 2009).
Figure 2.6: Soft-story mechanism (Richard, 2009)
13
Shear Wall System
A shear wall system comprises of reinforced concrete walls and slabs with rigid connections.
These shear walls are the integral resisting structural components to vertical and lateral loads and
also serve as architectural partitions. Shear walls have very high stiffnesses along their long
direction, making them perfect for resisting lateral loads and providing bracings for buildings.
Despite this, the capacity of the shear wall system to bear lateral forces highly depends on the
rigidity between the floor system and the walls (Moroni, 2011; The Constructor, 2012).
Shear walls are generally provided with tensile and compressive reinforcement, according to the
areas of occurring stresses. However, those located at the building exterior are designed also for
resisting moment and shear. Moreover, shear walls are ideal for buildings with repetitive floors
to allow them to extend from the bottom of the building to the top, unless alterations are required
due to commercial needs at ground floors and basements. Also, optimizing available floor space
can be done through using concrete of higher compressive strength for the construction of the
shear walls. Finally, they serve as excellent fire insulators. (Moroni, 2011; The Constructor,
2012)
Frame-Wall Structures
It has been explained that shear walls have an impressive lateral resistance, as they reflect high in
plane stiffnesses. This feature is taken advantage of by empowering rigid frame systems with
shear walls at adequate locations in the building plan, to increase the building’s overall lateral
resistance. The produced structural system is the frame-wall system, and is demonstrated in
Figure 2.7. This type of system is useful for repetitive floor buildings of elevations that have
surpassed the ranges used for rigid frames or shear wall systems alone. Frame-wall
collaborations produce stiffer structures due to the frame and wall horizontal interaction (The
Constructor, 2012).
Figure 2.7: Frame-wall structure (The Constructor, 2012)
14
Tube-in-Tube Structure
The tube-in-tube, or hull and core, structure is a type of framed tube structure. Its components
are an outer framed tube (hull) and an inner tube (core) which functions as an elevator and
service core. Both outer and inner tubes work together in withstanding vertical and lateral loads.
However, the outer tube has a much more significant structural depth and is of higher strength
than the inner core, and therefore devotes a greater contribution in bearing the imposed loads
(The Constructor, 2012). The tube-in-tube structure is shown in Figure 2.8.
Figure 2.8: Tube-in-tube structure (The Constructor, 2012)
15
2.2 Architectural Drawings Versus Structural Drawings
Any structural design project begins with architectural drawings and ends eventually with the
produced structural drawings. Therefore, these drawings are an essential associate to the
structural engineer throughout the span of the project, as they portray the features and conditions
of the structure through perceivable and manageable drawing sheets, and showcase the results of
all the design work conducted throughout. One of the integral and initial duties of a structural
engineer at the beginning of any project is to transform the primary architectural plan into a
structural plan. The structural plan serves as a good initiation step towards commencing with the
design procedures. Thus, it is crucial at this juncture to provide a detailed explanation for both
architectural and structural drawings, followed by a direct comparison between both.
2.2.1 Architectural Drawings
An architectural drawing represents a technical drawing of a building floor or project premises
from an architectural perspective. Architectural drawings are used by architects for many
objectives, as to evolve a design idea into a comprehendible and presentable finished proposal, in
order to discuss different views and perceptions with owners and highlight certain design merits
for persuading potential consumers. Furthermore, they are very influential to the initial pricing of
a project, depending on their quality, elaboration and sufficiency. Structural engineers use
architectural drawings to become well acquainted with the plan layout features and consequently
use them as templates to extract structural drawings. They also use them to facilitate the eventual
construction process on site.
Architectural drawings include elevations, floor plans, sections, site plans, landscape plans, roof
plans and reflected ceiling plans. With that being said, the most important of all architectural
drawings are the elevations, floor plans and sections. First of all, elevations provide side views of
different features of the building and clarify dimensions, levels, centerlines, exterior finishing
materials and cross referencing. They are better than any other drawing type in terms of
providing adequate presentation of the project’s style, size and complexity. In addition, they are
usually the first drawings executed because of their elaborate exhibitions, based on which the
owner can decide whether or not to approve of the elevation drawing before suffering any wasted
time on other drawings.
Secondly, floor plans are considered as the most important drawing and usually draw the most
attention. They provide a look down top view floor representation from mid-floor level, and
show important floor elements as walls, windows, doors and openings. They also display
external and internal dimensions, finishing materials, centerlines and cross referencing. Finally,
section drawings present a cutaway view in building elements. They aim to expose what exists
underneath the surface which the section cuts through. They illustrate important vertical aspects
as dimensions, levels, centerlines, finishing materials and cross referencing.
16
2.2.2 Structural Drawings
Structural drawings are concerned with the structural elements necessary for the erection of the
building. The main structural elements for any structure are foundations, columns, shear walls,
retaining walls, cores, slabs, beams and staircases. The structural plan is the heart of any
structural drawing and aims to exhibit the main structural elements of the building floor along
with the statical system, which defines their relationship within the load bearing structural
system. It shows the structural elements of the floor as seen from a look up plan view perspective,
positioned between the floor and ceiling of a single story. In addition, the structural plan
provides the locations of openings and lowered slabs. It also shows outer dimensions, beam
dimensions, slab thicknesses as well as certain indications as the finished floor level (FFL), top
of concrete (TOC) and slabs on grade.
Converting back to structural drawings; their main purpose is to provide the final concrete
dimensions for the structural elements along with sufficient steel reinforcement detailing. These
drawings are of pivotal importance to construction works as they are referred to during practical
implementation procedures on site. Structural drawings comprise of columns and axes drawings,
slab reinforcement drawings, beam reinforcement drawings and drawings for shallow and raft
foundations. Each drawing consists of a structural plan with information dedicated to the
intended structural element, accompanied by necessary section drawings, concrete dimensions
and elaborate steel reinforcement detailing to clarify steel bar shapes, length, distribution patterns
and quantities. Section drawings serve to display inner features of the structural members, and
are highly useful in providing further elaboration to steel bar distribution patterns within the
concrete cross section.
First, a columns and axes drawing comprises of a columns and axes plan, which shows columns,
cores, main axes and dimension lines demonstrating locations of all columns and cores from
their nearest axes. It also consists of section drawings for columns and cores showing elaborate
reinforcement detailing. Secondly, slab reinforcement drawings consist of a structural plan on
which the required slab reinforcement is drawn, as per design requirements. It also includes
section drawings for stairs and detailed drawings for openings reinforcement. Moreover, beam
reinforcement drawings contain a structural plan with labeled beam models, along with
reinforcement detailing in beams through typical elevation drawings. Also beam sections are
included for further clarification. Last, foundation drawings consist of a plan for the type of
foundation used with dimensions and steel reinforcement distribution. It also includes sectional
drawings for the foundation for further reinforcement clarification.
It is a common practice in structural drawings that plans are drawn to a scale of 1:100 and
sections to a scale of 1:25. If further elaboration for a specific aspect is desired, then a detail
drawing is drawn with a scale of 1:10, and is included in the final structural drawing. Finally,
structural drawings devote a section for practical implementation remarks to be referred to on
site. These include notations for particular reinforcement detailing guidelines and permissible
soil bearing capacity. They also provide notations for the stresses of the used building
components, as the concrete compressive strength and steel yield strength.
17
2.2.3 Comparison Between Architectural and Structural Drawings
To conclude, architectural drawings deal with the aesthetics of the building and represent it in its
finished state, where they show features as floor layouts and exterior wall details for instance. On
the other hand, structural drawings are more concerned with the structural system and with the
building components responsible for the structure’s erection and resistance to all imposed loads.
In addition, it provides information for the amounts of concrete and steel reinforcement needed
to set up the structure.
The most important architectural drawing is the architectural plan, and if we were to assign it to
its own comparison with its corresponding structural drawing, the structural plan, we would yield
the following conclusions. The architectural plan provides a look down view of the building
floor, and is concerned with internal room spaces where it shows contents of the floor as walls,
windows, doors and bathroom and kitchen elements, as well as indications for levels and
finishing materials. Conversely, the structural plan is a look up view of the building floor and
only demonstrates the main structural elements forming the building as columns, cores, slabs and
beams along with indications for beam dimensions and slab thicknesses. Figures 2.9 and 2.10
show examples of architectural and structural plans respectively.
Figure 2.9: Example of architectural plan (Allison, 2011)
Figure 2.10: Example of structural plan (Helal, 2012)
18
2.3 Computer-Based Softwares for Structural Purposes
In the modern era, the best structural engineers are those who are not only precise with their
work, but fast. Time efficiency along with accuracy have become substantial factors to a
successful engineer nowadays, due to the stiff competitiveness to outshine others, and also due to
the vigorous market demands and severe work loads. For this reason, manual work done by hand
is no longer sufficient. Whether performing structural analysis, design or drawings, hand efforts
are time consuming and can exhibit errors depending on the complexity of the work.
Consequently, computer-aided softwares are resorted to for improved quality and time efficiency.
Nowadays, these programs are a crucial escort to any structural engineer throughout their work.
2.3.1 SAP2000 for Structural Analysis
In practical work, conducting structural analysis procedures manually for a structure is very
challenging and troublesome. It is extremely time consuming, and involves a lot of detailed
structural calculations, and can therefore produce human errors. Thus, a structural analysis
program as SAP2000 is essential to ensure the quality, accuracy and speed of attaining the
desired results. Over the years, the SAP, or Structural Analysis Program, reputation for
displaying top-class analytical techniques has been unmatched. Whether a simple 2D frame
analysis or a sophisticated 3D dynamic model investigation, SAP has been nothing short of
impressive and fulfilling. SAP2000 provides a complex and multipurpose interface for users, and
is motored by a powerful analytical engine, for serving a wide range of fields (Computers and
Engineering, 2003).
SAP2000 is equipped with built in templates which can help users execute structural models with
significant ease. It also enables the import of DXF drawings; a feature which opens the door for
an even wider variety of uses. The main elements forming a 3D SAP model are joints, frames
and shells. Joints represent supports and intersections, while frames represent vertical or
horizontal members as beams, columns or frames, and finally shells represent vertical and
horizontal plates as shear walls, retaining walls and slabs. Henceforth, users are allowed to
assign element sections, with different materials and cross section shapes, and even optimize the
used material strength as per requirements. In addition, SAP2000 is equipped with an extrude
option, which is extremely useful for buildings with repetitive floors. Figure 2.11 shows a
preview of a 3D SAP model.
19
Figure 2.11: Example of a 3D SAP2000 model (Computers and Engineering, 2003)
Also available by SAP2000, loads, restraints, constraints and frame releases can be assigned for
the purpose of enhancing the accuracy of the model. Restraints refer to supports, with the user
left to choose their desired degree of freedom. Constraints provide rigid connections, to joints at
close ranges, in all or specific translation and rotary movements, as selected by the user.
Similarly, frame releases allow the release of forces or moments about frames, to distinguish the
secondary beams which are simply supported on the main beams (Computers and Engineering,
2003).
Regarding shells, SAP2000 prevents ‘shear locking’ dilemmas and also allows for the meshing
of shells with respect to grid intersections, specific number of shells, specific shell sizes or
intersections with selected joints. This is for model refinement and to obtain more accurate
results. Analysis results are displayed with reference to local axes to display forces, moments and
deflection directions in sublime elaboration for user interpretation. Furthermore, SAP2000
provides a graphical visualization of results by clicking on joints and members to showcase the
existing straining actions. Finally results can be printed in the form of reports or exported to
Excel or Access files, and even DXF drawings can be produced (Computers and Engineering,
2003).
20
2.3.2 Excel Spreadsheets for Structural Design
Microsoft Excel is a part of the Microsoft Office package from Microsoft Corporation. Excel is
the leading spreadsheet software worldwide, and can be used for endless purposes, from simple
everyday tasks, to in depth calculations and graphical representation. An Excel spreadsheet
comprises of a grid of cells placed in rows, which are represented by numbering, and columns,
represented by letters. In addition to this, it is equipped with arithmetic functions for
mathematical and statistical calculations, as well as data representation tools to preview data in
different forms, as graphs and charts (Harvey, 2006).
The structural design process of any structure involves a massive amount of repetitive work. This
is an immensely time consuming process if done manually, not to mention that it could produce a
plethora of human errors. With this being stated, quality and time are factors that must be
optimized during the design process. For these considerations, Excel spreadsheets are ideal for
structural design needs, as they are perfect for performing typical and repetitive calculations.
For preparing a design spreadsheet using excel, it is fed with the convenient design equations,
cases and iterations, depending on the design code in use and the structural element being
designed. These equations are defined through the mathematical functions provided by the Excel
software. Cells for input and output values on the spreadsheet are indicated to the user and to the
software as well, and the calculating procedures are conducted by the program.
Excel spreadsheets function by receiving design inputs as values of loads, moments, concrete
compressive strength, steel yield strength and concrete dimensions, and passing them through a
series of calculations as previously defined, to consequently produce outputs as the amount of
steel reinforcement, in their identified cell locations on the spreadsheet. The data representation
tools can be used to illustrate section views, showing concrete dimensions and steel
reinforcement for the structural member being designed.
Reliability is very important when using design spreadsheets, where the accuracy of results is
vital as there is no room for error in our line of work. Therefore, any spreadsheet produced needs
to be thoroughly reviewed for efficient functionality before being given the approval for usage.
A common practice done by design firms is protecting their spreadsheets with confidential
passwords so as to prevent any changes from occurring to the design functions, and also for
copyright purposes. Finally, the spreadsheet needs to be provided with a user friendly format,
where necessary considerations need to be made to inform the user of the input and output
whereabouts on the spreadsheet, and to understand its functionality as a whole.
21
2.3.3 AutoCAD for Structural Drawings
AutoCAD is a 2D and 3D computer-aided design program by Autodesk, Inc. It is used for
fabricating drawings without the need for drafting equipment and can produce anything from
floor plans to 3D models. Architects are the most frequent AutoCAD users where they utilize the
software to create blueprints and building specifications. Apart from architecture, AutoCAD is
used in a wide range of fields as structural, mechanical, interior and conception designs
(Education Portal, 2014).
The famous AutoCAD ribbon is the main user interface for selecting commands. A tremendous
aspect of the software is its ability to create several drawing layers, as this facilitates the drawing
procedures and visualizations. Its sublime ability to move pieces of a drawing from one place to
another and its endless features for manipulating lines and shapes, make it the optimal choice for
constructing complex drawings with a significant level of user content. In addition, it provides
printing options that are essential for producing elaborate drawings, where the plot window and
line thickness can be controlled.
One by one, AutoCAD is on track of demolishing the need for hand drawings, as it is much more
accurate, courtesy of its precise measurement system, and produces much more appealing
drawings. Other advantages of AutoCAD over hand drawings, are its lower time consumption to
produce the same drafting and its ability to draw figures with high levels of complex geometry.
All of this has directed structural engineers to using AutoCAD as an ideal drawing tool, rather
than hand drafting, due to its improved accuracy, time efficiency and printing versatility. In that
respect, structural engineers use AutoCAD to create their final structural drawings, where it
comes to great use when performing drawings with high levels of complexity, as reinforcement
detailings.
22
Chapter 3
Structural Design Spreadsheets Using Excel
This chapter is dedicated to the first part of the project; the development of structural design
Excel spreadsheets. The produced spreadsheets for this task follow the limit states of the
Egyptian Code for Design and Construction of RC Structures (ECP 203) and the Egyptian Code
for Load and Force Calculations (ECP 201), as per the project specifications. The purpose of the
spreadsheets is to work as structural design tools for the main structural members of a reinforced
concrete building. Furthermore, it is essential to point out that after the completion of each
spreadsheet; verifications were carried out to ensure its credibility and accuracy. As previously
mentioned in Chapter 2, spreadsheets are very widely used in structural design tasks, as they are
ideal for performing typical and repetitive work. As a result, they are very effective time savers
and play a significant role in avoiding human errors produced from hand calculations.
The contents of this chapter include discussions for the layout and coding done for each of the
spreadsheets, as well as the manner in which they were conducted to produce an output that was
both accurate and simple. This chapter also includes clarifications about the conducted validation
checks done for each spreadsheet. By the end of the project, a total of total 7 spreadsheets
comprising of 19 design tools were produced and divided among two Excel files. For sufficient
elaboration, a spreadsheet has been prepared for each of the following purposes: determining the
bracing condition of a building, classifying columns as short or long columns, design of short
columns in all possible cases, design of slabs, design of beams subjected to moment in all
possible case, design of beams for shear stress and deign of beams for torsional moment.
In addition to this, the spreadsheets were actually employed to further work, when they were
used in the design process of my midrise building project, which will be discussed throughout
the following chapter. For this reason, very precise time management was essential. For instance
I had to make sure that the Excel spreadsheet for design of a certain element was both completed
and validated before initiating with the actual design phase of that element of the building. This
had to be given immense consideration for improved time efficiency, and in order to follow the
proposed time schedule without any interruption.
23
3.1 Format and Style
My main objectives while preparing the Excel design spreadsheets, were simplicity, clarity and
accuracy. In order to simplify the format with which the spreadsheets were to be presented,
I divided them into two main Excel files, named “Design Tools Package 1: Columns” and
“Design Tools Package 2: Slabs and Beams”. The first Excel file or design package, named
“Design Tools Package 1: Columns” addresses everything concerning the design of columns,
which are the structural elements that mainly bear axial force. Conversely, “Design Tools
Package 2: Slabs and Beams” is dedicated to all the aspects of design regarding beams and slabs,
which are the structural elements that are mainly subjected to bending moment. Each of these
files includes more than one spreadsheet, and each spreadsheet contains one or more tools, where
each tool is responsible for a certain design aspect within the spreadsheet. I executed a total 7
design spreadsheets with 19 design tools among the two Excel files.
Furthermore, the spreadsheets themselves were prepared in a manner to have a simple and direct
interface, in order to improve their appeal towards the user. Also, I was very concerned with the
clarity of the contents of each spreadsheet, whether inputs, outputs or sequence of calculations.
In that respect, the two Excel files were each equipped with an introduction page. This
introduction page provides the user with indications of cells for input data, output information,
unsafe results and areas of informational remarks, which should be taken into consideration
while using the intended design tool. This way, the user would have a solid understanding of the
functionality and performance of the spreadsheet. For clarification, the introduction page for
“Design Tools Package 2: Slabs and Beams” is demonstrated in Figure 3.1.
Notes:
4- Cells with pink fill are either for clarifications or informational purposes.
3- If a cell turns RED, this indicates that the input needs to be rechecked.
Design Tools Package 2: Slabs and Beams
Prepared By:
Ahmed Wael Mohamed Khairy
1- Input data required from the user is indicated through cells with light blue fill.
2- Output data calculated is indicated through cells with green fill.
22-3786
Figure 3.1: Typical introduction page for my Excel spreadsheets
24
For further clarification purposes, I equipped each design tool with an extra piece of coding,
which is a conditional formatting function. Conditional formatting is a function used in
Microsoft Excel to change the formatting of a certain cell, should it attain a certain condition. I
used this function to change the colour of cells that produced values that fell out of their
permissible range of values, proving unsafe for the design. I set these cells to give a red colour
indicating that the values they contain are unsafe for the design and must be rechecked. Also, the
related cells which would need to be corrected were set to give a red colour as well, in order to
direct the user to the source of error. Indications for these cells are provided to the user within
the introduction page.
In addition, each spreadsheet is equipped with a converting tool, as shown in Figure 3.2, from
tons to kilonewtons in order to provide the user with more diversity, where straining action
values can be obtained in either of the two units, and converting between them can be conducted
directly through the spreadsheet. Also, for each spreadsheet there is an input area for the values
of compressive strength of concrete and yield strength for steel, as required by the user, and this
is also demonstrated in Figure 3.2. Furthermore, a comment column is available within all the
tools of each spreadsheet to verbally clarify the state of the design procedures for any
encountered situation. All the desirable equations from the ECP 203 were executed through
Microsoft Excel functions for addition, subtraction, multiplication, division, square root, power,
IF conditions, nested IF conditions, AND functions, OR functions and conditional formatting.
Regarding the accuracy of results, each design tool was checked thoroughly, and for all the cases
that may be encountered using actual solved examples for design of concrete elements according
to the Egyptian Code of Practice.
Ton.m 120 kN.m
N/mm2
N/mm2Steel Fy = 360
Ton.m to kN.m converter
1200
Concrete Fcu = 25
Figure 3.2: Unit converter and inputs for design stresses
25
3.2 Design Tools Package 1: Columns
This Excel file is dedicated to the design of columns. It consists of three design spreadsheets
comprising of eight design tools. The first spreadsheet, called “Columns Classification”, deals
with the classification of columns as short or long columns. In order to reach this deduction, the
building bracing condition is initially required. Thus, tool 1 is responsible for concluding
whether the building is considered braced or unbraced through acquiring certain inputs as the
number of building floors, building height, weight per unit area of the floor, total floor area and
the moment of inertia of the building due to the cores or shear walls in both horizontal and
vertical directions. The outputs include the building condition whether braced or unbraced in
each direction, and then the final bracing condition of the building, which can only be braced if
the building is braced in both directions together. I prepared tool 1 using the following guidelines
and equations obtained from the ECP 203 (2007):
- A building is considered unbraced if it doesn’t contain cores or shear walls.
- A building is considered braced if it contains cores or shear walls which are distributed
symmetrically and extend from the bottom to the top of the building, while satisfying the
following equation:
For buildings with 4 floors or more:
0.6bN
HEI
(3.1)
For buildings with less than 4 floors:
0.2 0.1N
Hb nEI
(3.2)
where
Hb = Building height above foundation level (meters)
N = Total working vertical loads for the building (kN)
E = 4400 cuf (kN/m2)
I = Moment of inertia for shear wall in horizontal or vertical direction (m4)
EI = Sum of all flexural rigidities for cores and shear walls in the considered direction.
n = Number of building floors.
26
Tools 2 and 3 are used for the classification of the column as a short or long column, and are
influenced by the bracing condition of the building as obtained from tool 1. Tool 2 is dedicated
to rectangular or square columns and tool 3 to circular columns. Inputs for tool 2 are the column
clear height, column dimensions and buckling factor depending on the column end conditions.
These inputs are required for both planes of the column. Another input required is the normal
force acting on the column. Inputs for tool 3 are similar. Outputs for tool 2 are the slenderness
ratios for both planes of the column and the final conclusion whether the column is considered a
short or long column. In case the column is found to be a long column, additional inputs are
provided as the buckling plane, the column deflection and the resultant value of additional
bending moment. Outputs for tool 3 are similar. Tools 2 and 3 were prepared with the aid of the
following conditions and equations as highlighted by the ECP 203 (2007):
- To determine if a column is a short or long column, its slenderness ratio is calculated and
compared with the slenderness ratio limits.
o
bkH
b (3.3)
where
b = Slenderness ratio
Ho = Clear height or buckling length of the column in the considered plane (meters)
b = Column dimension for the considered plane (meters)
k = Length factor depending on column end conditions and building bracing conditions.
Table 3.1: Limits of Slenderness Ratio for Short Columns (ECP 203, 2007)
Building Condition Slenderness Ratio for Rectangular Columns
t or b
Slenderness Ratio for Circular Columns
D
Braced 15 12
Unbraced 10 8
Table 3.2: Limits of Slenderness Ratio for Long Columns (ECP 203, 2007)
Building Condition Slenderness Ratio for Rectangular Columns
t or b
Slenderness Ratio for Circular Columns
D
Braced 30 25
Unbraced 23 18
27
- Values for k depend on the column end cases.
Table 3.3: Values of k for Braced Buildings (ECP 203, 2007)
End Condition at top End Condition at bottom
1 2 3
1 0.75 0.80 0.90
2 0.80 0.85 0.95
3 0.90 0.95 1.00
Table 3.4: Values of k for Unbraced Buildings (ECP 203, 2007)
End Condition at top End Condition at bottom
1 2 3
1 1.20 1.30 1.60
2 1.30 1.50 1.80
3 1.60 1.80 -
4 2.2 - -
where
Case 1
Column end is connected to the beams monolithically and the beam depth is greater than
or equal to the column dimension in the studied plane. This case also includes column
ends connected to moment resisting foundations.
Case 2
Column end is connected to the beams or slabs monolithically and the beam or slab depth
is less than the column dimension in the analyzed plane.
Case 3
Column end is connected with hinged joints, which are joints not designed to withstand
column rotation, yet give a small amount of restraint.
Case 4
Column end is free to both lateral and rotary motions, as in cantilever columns.
28
- In case the column is found to be a long column, an additional moment is induced.
b = 2
2000
b b (3.4)
.add uM P b (3.5)
where
b = Column deflection in critical buckling plane (m)
b = Column dimension in critical buckling plane (m)
Madd = Additional moment (kN.m)
Pu = Ultimate normal force on column (kN)
29
The following two spreadsheets are responsible for the design of short columns with all their
cases, whether rectangular or circular, and with known or unknown concrete dimensions. The
first of these two spreadsheets called “Short Columns 1”, is for the design of columns with
known concrete dimensions, and consists of two tools; tool 4 for rectangular columns and tool 5
for circular columns. Inputs are similar for the two tools, and are the ultimate load or normal
force acting on the column, column position (whether interior, edge or corner), column
dimensions, minimum steel reinforcement percentage (μ) and the required bar diameter. Outputs
include the concrete cross sectional area (Ac), the required area of steel reinforcement (As),
maximum and actual steel reinforcement percentages and finally the number of steel bars
required for the given bar diameter.
The final spreadsheet called “Short Columns 2”, addresses both the proportioning and design of
short columns with unknown concrete dimensions. It consists of three tools; tool 6 for
rectangular columns, tool 7 for square columns and tool 8 for circular columns. The inputs and
outputs are similar to those of the previous spreadsheet but with some differences, as the
objective of this spreadsheet is to conduct both proportioning and design procedures for columns.
Inputs include the ultimate load acting on the column, desired steel reinforcement percentage,
one initial column dimension and the required bar diameter. Outputs include the concrete cross
sectional area, the remaining concrete dimension, the required area of steel reinforcement and the
number of steel bars required for the desired bar diameter. Inputs, outputs and calculation
procedures are similar for all three tools of this spreadsheet. Figures 3.3 and 3.4 show
spreadsheets of “Design Tools Package 1: Columns”, as I utilized them for the implementation
of my 12 story building. Specifications and equations from the ECP 203 (2007) used to execute
spreadsheets “Short Columns 1” and “Short Columns 2”, are as follows:
- To design columns subjected to normal force:
0.35 0.67u cu c y sP f A f A (3.6)
where
Pu = Ultimate normal force on column (N)
Ac = Concrete cross sectional area (mm2)
As = Area of steel reinforcement (mm2)
fcu = Concrete compressive strength (N/mm2)
fy = Steel yield strength (N/mm2)
- Maximum reinforcement ratio in columns:
4% for interior columns
5% for exterior columns
6% for corner columns
30
12 floors 2000
37 meters
17.6 kN/m2 3.88
881.6 m2 0.8
0.6
3.88
0.8
0.25
N (kN) in X-
Direction
in Y-
Direction
Condition in Y-
Direction
b Out of
Planeb max Buckling Plane
186193.92 0.52 0.26 Braced 12.42 12.42 N/A
b N/A m
Madd = N/A kN.m
CLASSIFICATION OF BUILDING AS
BRACED OR UNBRACED
TOOL 1
CLASSIFICATION OF RECTANGULAR
COLUMN AS SHORT OR LONG COLUMN
TOOL 2
If Rectangular Column
kN
t Plane
meters
meters
b Plane
meters
General Building Information
Condition in X- Direction
m4
Total Moment of Inertia of Shear Walls in Y-direction
(Ix)151.74 m4
Total Floor Area
Average weight of 1 m2 of floor
Building Height
Conclusion
Short ColumnBraced
Total Moment of Inertia of Shear Walls in X-direction
(Iy)39.3678
t
Column Clear Height
K Buckling
b meters
Building is Braced
Normal Force
b In Plane
5.17
Number of Building Floors Including Ground Floor
Column Clear Height
K Buckling
Figure 3.3: My spreadsheet “Columns Classification” used in my midrise building project
b (mm) t (mm)
C1 1236 e 250 600 150000 5 0.8 -0.937 N/A 12 12 12 0.904779
C2 1710 e 250 600 150000 5 0.8 0.373 N/A 12 12 12 0.904779
C3 1149 e 250 600 150000 5 0.8 -1.177 N/A 12 12 12 0.904779
C4 2248 e 250 800 200000 5 0.8 0.307 N/A 16 12 16 1.206372
C5 4959 i 300 1300 390000 4 0.8 0.918 N/A 18 18 16 0.927978
C6 3779 i 250 1200 300000 4 0.8 0.869 N/A 12 18 18 1.526814
C7 4193 e 250 1200 300000 5 0.8 1.441 N/A 18 18 18 1.526814
C8 2869 e 300 1300 390000 5 0.8 -1.303 N/A 16 16 16 0.824869
C9 2125 e 300 1300 390000 5 0.8 -2.094 N/A 16 16 16 0.824869
C10 3397 i 250 1000 250000 4 0.8 1.280 N/A 16 16 16 1.286796
C11 3322 i 250 1000 250000 4 0.8 1.156 N/A 16 16 16 1.286796
C12 2585 i 250 800 200000 4 0.8 1.005 N/A 12 12 16 1.206372
C13 6267 i 450 1100 495000 4 0.8 0.896 N/A 18 18 18 0.925342
C14 2613 i 250 800 200000 4 0.8 1.063 N/A 12 12 16 1.206372
C15 2540 i 250 800 200000 4 0.6 0.912 N/A 10 12 16 1.206372
C16 4806 i 450 800 360000 4 0.6 1.182 N/A 14 14 20 1.22173
Column actual
(%)
Ultimate Load
(kN)Ac (mm2)
Required Ac to be
reached (mm2)
Column
Position
(i,e,c)
max
(%)
16
18
18
16
12
12
12
Normal proceedings (SAFE)
Normal proceedings (SAFE)
16
16
16
Column DimensionsComment
Reinforcement
Enter bar
diameter (mm)
no. of steel
bars
12
min
(%)As required (mm2)
Minimum As required (SAFE)
Minimum As required (SAFE)
Minimum As required (SAFE)
Minimum As required (SAFE)
1200.00
1200.00
1200.00
1600.00
Normal proceedings (SAFE)
Normal proceedings (SAFE)
Normal proceedings (SAFE)
Minimum As required (SAFE)
Minimum As required (SAFE)
3582.09
2607.79
4324.21
3120.00
3120.00
4434.08 Normal proceedings (SAFE)
2126.87 Normal proceedings (SAFE)
1824.21 Normal proceedings (SAFE)
3200.66
2889.72
4253.73 20Normal proceedings (SAFE)
18
16
16
2010.78 Normal proceedings (SAFE) 16
bar
diameter
actual
(%)
Actual Reinforcement
no. of steel
bars
DESIGN OF RECTANGULAR COLUMN WITH KNOWN CONCRETE DIMENSIONS
TOOl 4
Figure 3.4: My spreadsheet “Short Columns 1” used in my midrise building project
31
3.3 Design Tools Package 2: Slabs and Beams
This Excel file serves the design of both slabs and beams. It comprises of four design
spreadsheets with eleven design tools. The first spreadsheet is called “Slabs” and consists of tool
9 which addresses the design of slab systems. The inputs for this tool are the value of ultimate
bending moment acting on the concrete section, the section dimensions (breadth and depth) and
the bar diameter. Outputs include values for C1 and J, minimum and actual areas of steel
reinforcement and the number of steel bars for the required bar diameter.
The following spreadsheet, named “Beams Designed for Moment”, aims to design beams for
bending moment, and covers all the possible situations, whether designing R-sections, T-sections
or L-sections, in both cases of known and unknown concrete dimensions. It consists of eight
tools, where tool 10 is for the design of R-sections with known concrete dimensions and tool 11
for the proportioning and design of R-sections with unknown concrete dimensions. Similarly,
tool 12 concerns the design of T or L-sections with known concrete dimensions and tool 13 is
used for the proportioning and design of T or L-sections with unknown concrete dimensions.
Tools 14 – 17 address further reinforcement notes for each of the previous four cases, as will be
explained before long.
Inputs for tools 10 and 12 include the ultimate bending moment value, beam dimensions (breadth
and depth) and required bar diameter. However for tools dealing with both the proportioning and
design of sections having unknown concrete dimensions, as tool 11 and 13, the inputs consist of
the ultimate bending moment value, the breadth of the beam, the value of C1 and the bar
diameter. Outputs for tools 10 and 12 are the values of C1 and J, minimum and actual areas of
steel reinforcement and the number of steel bars for the given bar diameter. Outputs for tools 11
and 13 include the value of J, the beam depth, minimum and actual areas of steel reinforcement
and the number of steel bars required for the inputted diameter.
As previously mentioned, tools 14 – 17 provide additional information for reinforcement, for
each of the previous four tools. These outputs are the maximum number of bars in one row, the
consequent number of rows required, the amount of required stirrup hangers and the quantity and
spacing of shrinkage bars for beams with depths greater than 700 mm. The following equations
and guidelines, obtained from my previous handouts for the reinforced concrete courses, were
used in the preparation of the spreadsheets “Slabs” and “Beams Designed for Moment” (El-
Leathy, 2009).
32
- To design beam sections subjected to bending moment:
1UL
cu
Md C
f b (3.7)
ULs
y
MA
Jf d (3.8)
- Minimum area of steel reinforcement:
1.1
y
bdf
1.3 reqAs
d = Beam depth (mm)
b = Beam breadth (mm)
Mul = Ultimate bending moment on the beam section (N.mm)
As = Area of steel reinforcement (mm2)
fcu = Concrete compressive strength (N/mm2)
fy = Steel yield strength (N/mm2)
smaller
0.15
100bd
bigger (3.9)
33
- Effective width (B) for T-sections:
CLslab – CLslab
16 ts + b
5
LK b
- Effective width (B) for L-sections:
CLbeam – CLslab
6 ts + b
10
LK b
where K = 1 0.8 0.7
- Area of steel reinforcement required for stirrup hangers in beams = 0.2 As used
- Maximum number of steel bars in a single row for beams:
25
25
bn
(3.10)
(where is the steel bar diameter)
smaller smaller
34
My third spreadsheet, called “Check Shear”, consists of tool 18 which deals with the design of
beams due to shear force. It aims at providing the amount of stirrups required for the beam to
withstand the values of shear force subjected on it. The inputs are the shear force value, beam
dimensions, the diameter of used stirrups and the number of stirrup branches. Outputs are the
minimum, maximum and actual values of shear stress on the beam, the spacing between stirrups,
the number of stirrups per meter and the actual number of stirrup branches required. The
following equations and cases from the ECP 203 were used to prepare this spreadsheet:
- To conclude whether or not a beam requires shear reinforcement calculations:
crU
bd (3.11)
0.24 cucu
c
fq
(3.12)
max
0.7 cuU
c
fq
(3.13)
where
qu = Actual shear stress on beam (N/mm2)
qcu = Shear stress resistance by concrete only with no reinforcement (N/mm2)
qumax = Shear stress resistance by concrete and maximum shear reinforcement (N/mm2)
Qcr = Maximum shear force at critical section (N)
c = Reduction factor for fcu taken as 1.5
If qu ≤ qcu Use minimum shear reinforcement which is 5 8 /m
If qcu < qu ≤ qumax Beam requires shear reinforcement calculations.
If qu > qumax Shear stress on the beam is unsafe and cross section dimensions need to
be increased.
35
- In case we need to calculate shear reinforcement for the beam:
y
st
s
su
fnA
qbS
(3.14)
where
qsu = Shear stress resistance by stirrups alone = qu – 0.5 qcu (N/mm2)
n = Number of stirrup legs
Ast = Cross sectional area of one stirrup (mm2)
b = Beam width (mm)
fy = Stirrup steel yield strength (N/mm2)
S = Spacing between stirrups and cannot exceed 200 mm or fall below 100 mm
s = Reduction factor for fy taken as 1.15
If S ≥ 200 mm Use minimum shear reinforcement which is 5 8 /m
If 100 ≤ S ≤ 200 Use number of stirrups equal to 1000/S
If S < 100 mm Stirrups will be packed too close, so try another assumption as ordered:
n
Assumption 1 2 8
Assumption 2 2 10
Assumption 3 4 8
Assumption 4 4 10
(where n = number of stirrup legs and = stirrup diameter)
Important Remark
If b ≥ 400 mm use 4 stirrup legs (n = 4)
36
The fourth and final spreadsheet is dedicated to the design of beams due to torsional moment and
is named “Check Torsion”. It comprises of tool 19, and its purpose is to obtain the amount of
closed stirrups and longitudinal bars required to resist the torsional moment on the beam. The
inputs are the value of torsional moment, beam dimensions and diameter of closed stirrups.
Outputs are the values of minimum, maximum and actual torsional stresses on the beam, the
spacing between stirrups, the number of closed stirrups per meter, the actual number of stirrup
branches and the values of minimum and actual cross sectional area for longitudinal bars within
the section. It is significant to point out that, Figures 3.5 to 3.8 exhibit the spreadsheets I used
from “Design Tools Package 2: Slabs and Beams” in the design process of my midrise building
project. Finally, I referred to the ECP 203 for the following equations and cases in order to
implement the spreadsheet “Check Torsion”:
- To conclude whether or not a beam requires additional torsional reinforcement:
1.7
tutu
oh e
Mq
A t (3.15)
ohe
h
At
P (3.16)
min 0.06 cutu
c
fq
(3.17)
max 0.7 cutu
c
fq
(3.18)
where
qtu = Shear stress developed from ultimate torsional moment on the beam (N/mm2)
qtumin = Minimum allowable torsional stress without additional reinforcement (N/mm2)
qtumax = Maximum torsional stress allowable without increasing dimensions (N/mm2)
Mtu = Ultimate torsional moment on the beam (N.mm)
Aoh = Area enclosed within the outermost stirrup (mm2)
Ph = Perimeter of stirrup (mm)
If qtu ≤ qtumin Use minimum reinforcement which is 5 8 /m
If qtumin < qtu ≤ qtumax Beam requires torsional reinforcement; closed stirrups and
longitudinal bars.
If qtu > qtumax Shear stress on the beam is unsafe and cross section dimensions need to
be increased.
37
- If the beam requires torsional reinforcement, it needs both closed stirrups and longitudinal
bars.
- To determine the amount of closed stirrups:
1.7
tustr
y st
oh
s
M SA
fA
(3.19)
where
Astr = Cross sectional area of one closed stirrup (mm2)
fyst = Stirrup steel yield strength (N/mm2)
S = Spacing between closed stirrups and cannot exceed 200 mm or fall below 100 mm
If S ≥ 200 mm Use minimum reinforcement which is 5 8 /m
If 100 ≤ S ≤ 200 Use number of stirrups equal to 1000/S
If S < 100 mm Stirrups will be packed too close, so try another assumption as ordered:
ϕ
Assumption 1 8
Assumption 2 10
Assumption 3 12
- To obtain quantity of longitudinal bars, we refer to equation 3.20, while making sure it is not
less than the minimum amount from equation 3.21, then we distribute the cross sectional area
of longitudinal bars among the 4 sides of the beam:
yststr h
sl
y
fA PA
S f
(3.20)
min
0.4
/
cucp
ystc str hsl
y s y
fA
fA PA
f S f
(3.21)
where
Asl = Cross sectional Area of longitudinal bars (mm2)
Acp = Total cross sectional area of beam including openings (mm2)
Important Remarks
Maximum distance between longitudinal bars = 300 mm
Minimum bar diameter for longitudinal bars = 12 mm
38
1 7 1000 100 6.55 0.826 305.56 305.56
2 6 1000 90 6.36 0.826 275.00 275.00
3 14 1000 100 4.63 0.822 305.56 473.14
4 17 1000 100 4.20 0.811 305.56 582.39
5 25 1000 100 3.46 0.780 305.56 890.88
6 10 1000 100 5.48 0.826 305.56 336.29
7 22 1000 100 3.69 0.792 305.56 772.02
8 19 1000 100 3.97 0.803 305.56 657.05
9 12 1000 100 5.00 0.826 305.56 403.55
10 11 1000 100 5.22 0.826 305.56 369.92
11 12 1000 100 5.00 0.826 305.56 403.55
12 10 1000 90 4.93 0.826 275.00 373.66
13 11 1000 90 4.70 0.823 275.00 412.29
Section
Ultimate
Moment
(kNm)
Breadth
b (mm)
Depth d
(mm)C1 J
As min
(mm2)
As used
(mm2)Comment
Reinforcement
Enter bar diameter
(mm)no. of steel bars
Normal Proceedings (safe) 12 5
Normal Proceedings (safe) 12 6
As < As min, As min used (safe) 10 4
As < As min, As min used (safe) 10 4
Normal Proceedings (safe) 12 7
Normal Proceedings (safe) 12 6
Normal Proceedings (safe) 12 8
Normal Proceedings (safe) 10 5
Normal Proceedings (safe) 10 6
Normal Proceedings (safe) 10 5
Normal Proceedings (safe) 10 6
Normal Proceedings (safe) 10 5
TOOL 9
DESIGN OF SLABS
Normal Proceedings (safe) 10 6
Figure 3.5: My spreadsheet “Slabs” used in my midrise building project
1 1 250 650 56.29 0.826 243.75 243.75
2 50 250 650 7.96 0.826 336.29 336.29
3 51 250 650 7.88 0.826 343.02 343.02
4 67 250 650 6.88 0.826 450.63 450.63
5 68 250 650 6.83 0.826 457.36 457.36
6 59 250 650 7.33 0.826 396.83 396.83
7 60 250 650 7.27 0.826 403.55 403.55
8 116 250 650 5.23 0.826 496.53 600.15
9 98 250 650 5.69 0.826 496.53 507.03
10 99 250 650 5.66 0.826 496.53 512.20
3
3
2
3Normal Proceedings (safe)
12
12
12
12
16
16
16
18
18
SectionUltimate
Moment (kNm)
Breadth
b (mm)C1 J
Depth d
(mm)
As < As min, As min used (safe)
As < As min, As min used (safe)
As < As min, As min used (safe)
As < As min, As min used (safe)
CommentAs min
(mm2)
As used
(mm2)
As < As min, As min used (safe)
As < As min, As min used (safe)
As < As min, As min used (safe)
TOOL 10
DESIGN OF RECTANGULAR SECTION WITH KNOWN CONCRETE
DIMENSIONS
no. of steel bars
3
Reinforcement
Normal Proceedings (safe)
Normal Proceedings (safe)
Enter bar diameter
(mm)
12
3
4
4
5
2
Figure 3.6: My spreadsheet “Beams Designed for Moment” used in midrise building project
39
BeamShear Force Q
(kN)
Breadth b
(mm)
Depth d
(mm)
qcu
(N/mm2)
qu
(N/mm2)
qu max
(N/mm2)n
ϕ
(mm)
Spacing S
(mm)
1 53 250 650 1.07 0.33 3.13 2 8 N/A 5 ϕ 8 2 branches
2 66 250 650 1.07 0.41 3.13 2 8 N/A 5 ϕ 8 2 branches
3 78 250 650 1.07 0.48 3.13 2 8 N/A 5 ϕ 8 2 branches
4 86 250 650 1.07 0.53 3.13 2 8 N/A 5 ϕ 8 2 branches
5 117 250 650 1.07 0.72 3.13 2 8 N/A 5 ϕ 8 2 branches
6 98 250 650 1.07 0.60 3.13 2 8 N/A 5 ϕ 8 2 branches
7 72 250 650 1.07 0.44 3.13 2 8 N/A 5 ϕ 8 2 branches
8 27 250 650 1.07 0.17 3.13 2 8 N/A 5 ϕ 8 2 branches
9 57 250 650 1.07 0.35 3.13 2 8 N/A 5 ϕ 8 2 branches
10 52 250 650 1.07 0.32 3.13 2 8 N/A 5 ϕ 8 2 branches
11 74 250 650 1.07 0.46 3.13 2 8 N/A 5 ϕ 8 2 branches
12 27 120 650 1.07 0.35 3.13 2 8 N/A 5 ϕ 8 2 branches
13 96 250 650 1.07 0.59 3.13 2 8 N/A 5 ϕ 8 2 branches
14 90 450 650 1.07 0.31 3.13 2 8 N/A 5 ϕ 8 4 branches
15 176 250 650 1.07 1.08 3.13 2 8 153.58 7 ϕ 8 2 branches
16 138 250 650 1.07 0.85 3.13 2 8 N/A 5 ϕ 8 2 branches
17 102 250 650 1.07 0.63 3.13 2 8 N/A 5 ϕ 8 2 branches
18 103 250 650 1.07 0.63 3.13 2 8 N/A 5 ϕ 8 2 branches
19 14 250 650 1.07 0.09 3.13 2 8 N/A 5 ϕ 8 2 branches
20 48 250 650 1.07 0.30 3.13 2 8 N/A 5 ϕ 8 2 branches
21 22 120 650 1.07 0.28 3.13 2 8 N/A 5 ϕ 8 2 branches
22 72 250 650 1.07 0.44 3.13 2 8 N/A 5 ϕ 8 2 branches
23 38 250 650 1.07 0.23 3.13 2 8 N/A 5 ϕ 8 2 branches
24 45 250 650 1.07 0.28 3.13 2 8 N/A 5 ϕ 8 2 branches
25 111 450 650 1.07 0.38 3.13 2 8 N/A 5 ϕ 8 4 branches
qu < qcu, Use 5 ϕ 8/m
qu < qcu, Use 5 ϕ 8/m
Comment
qu < qcu, Use 5 ϕ 8/m
qu < qcu, Use 5 ϕ 8/m
Shear Reinforcement
qu < qcu, Use 5 ϕ 8/m
qu < qcu, Use 5 ϕ 8/m
qu < qcu, Use 5 ϕ 8/m
qu < qcu, Use 5 ϕ 8/m
N/A
Further Comment
qu < qcu, Use 5 ϕ 8/m
qu < qcu, Use 5 ϕ 8/m
qcu < qu < qu max, Proceed for Shear Rft. Calculations
qu < qcu, Use 5 ϕ 8/m
qu < qcu, Use 5 ϕ 8/m
qu < qcu, Use 5 ϕ 8/m
qu < qcu, Use 5 ϕ 8/m
qu < qcu, Use 5 ϕ 8/m
qu < qcu, Use 5 ϕ 8/m
qu < qcu, Use 5 ϕ 8/m
qu < qcu, Use 5 ϕ 8/m
qu < qcu, Use 5 ϕ 8/m
N/A
N/A
100 < S < 200 (SAFE)
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
TOOL 18
CHECK SHEAR STRESS
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
qu < qcu, Use 5 ϕ 8/m
qu < qcu, Use 5 ϕ 8/m
qu < qcu, Use 5 ϕ 8/m
qu < qcu, Use 5 ϕ 8/m
qu < qcu, Use 5 ϕ 8/m
Figure 3.7: My spreadsheet “Check Shear” used in my midrise building project
ϕ
(mm)
Spacing S
(mm)AsLB (mm2)
AsLB min
(mm2)
AsLB used
(mm2)
AsLB/4
(mm2)
1 15 250 700 0.27 0.89 3.13 8 154.56 7 ϕ 8 2 branches 368.59 631.43 631.43 157.86
2 6.5 250 700 0.27 0.38 3.13 8 356.67 5 ϕ 8 2 branches 159.72 840.30 840.30 210.07
3 20 250 700 0.27 1.18 3.13 8 115.92 9 ϕ 8 2 branches 491.45 508.57 508.57 127.14
4 16 250 700 0.27 0.95 3.13 8 144.90 7 ϕ 8 2 branches 393.16 606.86 606.86 151.71
5 9 250 700 0.27 0.53 3.13 8 257.59 5 ϕ 8 2 branches 221.15 778.87 778.87 194.72
6 15 250 700 0.27 0.89 3.13 8 154.56 7 ϕ 8 2 branches 368.59 631.43 631.43 157.86
7 14 250 700 0.27 0.83 3.13 8 165.60 7 ϕ 8 2 branches 344.02 656.00 656.00 164.00
8 13 250 700 0.27 0.77 3.13 8 178.33 6 ϕ 8 2 branches 319.44 680.57 680.57 170.14
9 5 250 700 0.27 0.30 3.13 8 463.67 5 ϕ 8 2 branches 122.86 877.16 877.16 219.29
10 16 250 700 0.27 0.95 3.13 8 144.90 7 ϕ 8 2 branches 393.16 606.86 606.86 151.71
11 2 250 700 0.27 0.12 3.13 8 N/A 5 ϕ 8 2 branches N/A N/A N/A N/A
12 0.5 120 700 0.27 0.20 3.13 8 N/A 5 ϕ 8 2 branches N/A N/A N/A N/A
13 6 250 700 0.27 0.36 3.13 8 386.39 5 ϕ 8 2 branches 147.44 852.58 852.58 213.15
14 0.5 450 700 0.27 0.01 3.13 8 N/A 5 ϕ 8 4 branches N/A N/A N/A N/A
15 250 700 0.27 0.00 3.13 8 N/A 5 ϕ 8 2 branches N/A N/A N/A N/A
16 20 250 700 0.27 1.18 3.13 8 115.92 9 ϕ 8 2 branches 491.45 508.57 508.57 127.14
17 3.5 250 700 0.27 0.21 3.13 8 N/A 5 ϕ 8 2 branches N/A N/A N/A N/A
18 15.5 250 700 0.27 0.92 3.13 8 149.57 7 ϕ 8 2 branches 380.88 619.14 619.14 154.79
19 1 250 700 0.27 0.06 3.13 8 N/A 5 ϕ 8 2 branches N/A N/A N/A N/A
20 10 250 700 0.27 0.59 3.13 8 231.83 5 ϕ 8 2 branches 245.73 754.29 754.29 188.57
21 1 120 700 0.27 0.41 3.13 8 811.42 5 ϕ 8 2 branches 59.47 420.54 420.54 105.13
22 4 250 700 0.27 0.24 3.13 8 N/A 5 ϕ 8 2 branches N/A N/A N/A N/A
23 0.5 250 700 0.27 0.03 3.13 8 N/A 5 ϕ 8 2 branches N/A N/A N/A N/A
24 13 250 700 0.27 0.77 3.13 8 178.33 6 ϕ 8 2 branches 319.44 680.57 680.57 170.14
25 0.5 450 700 0.27 0.01 3.13 8 N/A 5 ϕ 8 4 branches N/A N/A N/A N/A
qt min < qtu < qu max, Proceed for Torsional Design
qt min < qtu < qu max, Proceed for Torsional Design
qt min < qtu < qu max, Proceed for Torsional Design
Reinforcement
qt min < qtu < qu max, Proceed for Torsional Design
qt min < qtu < qu max, Proceed for Torsional Design
qt min < qtu < qu max, Proceed for Torsional Design
qt min < qtu < qu max, Proceed for Torsional Design
qtu < qt min, Use 5 ϕ 8/m
100 < S < 200 (SAFE)
N/A
qt min < qtu < qu max, Proceed for Torsional Design
qt min < qtu < qu max, Proceed for Torsional Design
qt min < qtu < qu max, Proceed for Torsional Design
100 < S < 200 (SAFE)
S > 200, Use 5 ϕ 8 (SAFE)
N/A
N/A
100 < S < 200 (SAFE)
qtu < qt min, Use 5 ϕ 8/m
qt min < qtu < qu max, Proceed for Torsional Design
qtu < qt min, Use 5 ϕ 8/m
N/A
S > 200, Use 5 ϕ 8 (SAFE)
qt min < qtu < qu max, Proceed for Torsional Design
qtu < qt min, Use 5 ϕ 8/m
S > 200, Use 5 ϕ 8 (SAFE)
S > 200, Use 5 ϕ 8 (SAFE)
N/A
qtu < qt min, Use 5 ϕ 8/m
qt min < qtu < qu max, Proceed for Torsional Design
qtu < qt min, Use 5 ϕ 8/m
N/A
100 < S < 200 (SAFE)
N/A
qtu
(N/mm2)
100 < S < 200 (SAFE)
S > 200, Use 5 ϕ 8 (SAFE)
100 < S < 200 (SAFE)
100 < S < 200 (SAFE)
TOOL 19
CHECK TORSIONAL MOMENT
100 < S < 200 (SAFE)
S > 200, Use 5 ϕ 8 (SAFE)
100 < S < 200 (SAFE)
Closed Stirrups
Beam
Torsional
Moment Mtu
(kNm)
Breadth b
(mm)
Thickness t
(mm)
qt min
(N/mm2) Further Comment
qu max
(N/mm2)Comment
Longitudinal Bars
qt min < qtu < qu max, Proceed for Torsional Design
qtu < qt min, Use 5 ϕ 8/m
qt min < qtu < qu max, Proceed for Torsional Design
qtu < qt min, Use 5 ϕ 8/m
N/A
100 < S < 200 (SAFE)
N/A
qtu < qt min, Use 5 ϕ 8/m
qt min < qtu < qu max, Proceed for Torsional Design
Figure 3.8: My spreadsheet “Check Torsion” used in my midrise building project
40
3.4 Verification of Excel Spreadsheet Results
The accuracy of the obtained results from my Excel spreadsheets was of great importance to me.
I wanted to execute design spreadsheets that can be acknowledged as top of the line spreadsheets
by the most prestigious of structural design firms, and be relied on to obtain the most accurate of
results. In order to achieve this level of desired accuracy and credibility, I assured the validity of
each spreadsheet design tool by comparing its results with actual solved examples I acquired
from my previous handouts for the reinforced concrete courses (El-Leathy, 2009).
Moreover, results were checked for all the possible cases that could be faced, even those I would
not encounter during the design of my midrise reinforced concrete building. This was to confirm
the validity of the spreadsheets throughout all the possible situations of design. As a conclusion,
all values from my spreadsheets emerged to be identical to the results of the confirmation
examples. I can honestly say that I can heavily depend on these spreadsheets for use in the
implementation of the 12 story reinforced concrete building, and in any future project
requirements, even beyond the bachelor project level. Detailed verification examples along with
the corresponding results of my spreadsheets can be found in Appendix A.
41
Chapter 4
Design and Detailing of Midrise RC Building
This chapter discusses in detail all the tasks that were carried out for the completion of the
second part of the project; the design and detailing of a midrise reinforced concrete building
following the guidelines and limit states of the ECP 203 and ECP 201. It is important to point out
that the previously prepared Excel spreadsheets were used in the design procedures of this
branch project. To commence, the initial specifications and information for the building are as
follows:
The building consists of 12 floors
Typical floor height = 3 meters, and ground floor height = 4 meters
Typical floor dimensions = 34.45 x 25.85 m2
Compressive strength for used concrete = 30 MPa
Yield strength for used steel = 360 MPa
The underlying soil was compacted in several layers to reach a bearing capacity of 200
kN/m2
The floor system I selected was the solid slab system, and this was due a productive reason. I
initially knew that the foundation system I would implement would be a raft foundation, as it
was the most suitable given my building height and the soil properties. Consequently, the method
of design of the raft foundation system was very similar to that of the flat slab floor system. For
this reason, I chose to implement another type of floor system, the solid slab system, so as to
emerge from the project having learnt about two methods of floor systems, instead of one.
Throughout this chapter, a thorough explanation will be given for each task that was conducted
to implement the midrise building starting from the architectural plan, and ending with the final
produced structural drawings, followed by quantity estimation and cost analysis investigations.
All tasks are ordered according to their actual and logical order of execution.
42
4.1 Drawing Architectural Plan
Any structural design project begins with an architectural plan. At the very beginning of the
project, I was handed an initial architectural typical floor plan by my thesis supervisor (Notes,
2014). I immediately started drawing this architectural plan using AutoCAD so that it would
serve as a template to help me produce the following structural plans. This task was very
beneficial as it enhanced my AutoCAD skills and made me more acquainted with the interface,
as well as making me more aware of the detail whereabouts and dimensions of the floor plan I
was to work on for the following three months of the project.
The typical floor of the building consisted of 4 identical apartments; each with 7 rooms, 4
balconies, 4 bathrooms and a kitchen. In addition to this, the building consisted of 2 pairs of
cores, where each pair consisted of 2 identical ones; such that one pair surrounds 2 staircases,
while the other shelters 2 elevator shafts. Figure 4.1 shows the initial architectural plan handed at
the beginning of the project, and figure 4.2 displays the produced project architectural plan.
Figure 4.1: Initial Architectural Plan
43
Fig
ure
4.2
: P
roje
ct
Arc
hit
ectu
ral
Pla
n
44
4.2 Selecting Statical System and Drawing Structural Plan
At this point, it was necessary to decide on the statical system for the floor, and consequently
portray it through a structural plan. This is a crucial task in any structural design project, as the
structural plan puts the structural engineer on firm ground, and provides a significant vision of
the studied floor from his perspective. It paves the way for the remainder of the project tasks,
where it enables progressing to the structural analysis phase of the floor plan, followed by the
structural design phase and ending with the structural drawings, as a closure to the project.
Firstly, the statical system refers to the manner in which the structural elements of the building
work together to transfer the loads from one another, and finally convert them to the soil layers.
For deciding on the statical system, it was a main concern for me to decrease the number of
columns as much as possible in order to emerge with a design that would be both economic and
aesthetic. In that respect, I removed some nonessential columns from the architectural plan, with
careful regard to the allowable distances between them, where columns should be placed at
distances of 3-7 meters apart as a common practice in solid slab systems.
Regarding beams, I chose to place them above walls. Furthermore, due to the omitting of some
columns, I decided on the beams that would be considered as primary beams and those as
secondary ones. Also, some additional beams were added in order to divide big spans of slabs, to
avoid any deflection concerns. Hence, the final positions for columns, cores, beams and slabs
were decided on, and it was instantly required to showcase these features through the structural
plan.
It is essential to point out, at this juncture, the main differences between structural and
architectural plans, as referred to in Chapter 2. The structural plan provides a look up plan view,
while the architectural plan contributes with a look down one. Moreover, the structural plan only
shows reinforced concrete elements, as slabs, beams, columns and cores as well as voids and
openings. Doors, door paths, windows and interior room elements exist only in architectural
plans, and had to be excluded while producing the structural plan.
In that respect, the architectural plan AutoCAD drawing, which I had previously executed, was
then used to yield the structural plan. Any architectural features were abandoned, and only the
structural elements of the floor, as beams columns, cores and slabs, were shown. Columns, cores
and depressed slabs are indicated by hatching, while slab thicknesses as well as beam dimensions
are all visible on the plan.
The first draft of the structural plan comprised of the dimensioning obtained from the
preliminary proportioning phase, as will be discussed in the following section. With that being
stated, the final and exact dimensions can only be achieved after the detailed design phase, and
thus, the structural plan should be continuously updated until reaching the eventual dimensions
as per design requirements. Figure 4.3 shows the final structural plan for the typical floor of the
building.
45
Fig
ure
4.3
: Fin
al
Str
uctu
ral P
lan
46
4.3 Preliminary Proportioning of Structural Elements
The purpose of the preliminary proportioning phase is to provide initial dimensions for the main
reinforced concrete structural elements, in order to use them as starting values in the detailed
design process. The detailed design process then investigates the relevance and sustainability of
these initial propositions, for either reassurance or amendment. The Egyptian Code for Design
and Construction of Reinforced Concrete Structures (ECP 203, 2007) is referred to in order to
attain these initial values in a safe, reliable and reasonable manner, as per the following
guidelines:
For Columns
- Minimum column dimensions = 25 cm x 25 cm.
For Beams
- Beam width = wall width (12 cm or 25 cm)
- Minimum beam depth = 40 cm
- Beam depth is related to span where:
For simple beams: depth = span/10
For continuous beams: depth = biggest span/ 12
For Solid Slabs
- Minimum slab thickness = 12 cm.
- Rectangularity (r) of slabs determines whether it is a one way slab or a two way slab:
` s
mLr
m L
m or m` = 1 0.87 0.76
If r > 2 ∴ the slab is a one way slab
If r ≤ 2 ∴ the slab is a two way slab
47
- Values for slab thickness without the need to check for deflection:
One way slabs: Ls /25 Ls /30 Ls /36
Two way slabs: Ls /35 Ls /40 Ls /45
(where Ls is the shorter side length of the slab)
First of all regarding columns, initial dimensions were obtained from designing them by using
the area method technique. To start, I considered the majority of column widths to be 25 cm, so
as to be embedded within the walls without occupying any further room space for aesthetic
purposes. Then, the floor plan was divided into areas to be assigned to the columns based on
their positions, which would, in turn, determine their eventual load capacities.
Next, the weight per unit floor area had to be calculated, and so I referred to the Egyptian Code
for Load and Force Calculations to obtain the appropriate load assignments, with which I would
calculate the floor weight (ECP 201, 2012). Residential building load assignments obtained from
the ECP 201 are as follows: live loads are valued at 2 kN/m2 for the floor area, except for stairs,
kitchens, bathrooms and balconies where they are considered to be 3 kN/m2, while floor cover
load is taken as 1.5 kN/m2 throughout.
I also manually calculated the weight of beams per unit floor area, in order to contribute to the
total floor weight, and I also included a value of 2 kN/m2 for wall loads. The objective was to
acquire the weight of all elements that would impose loads on columns, and so the final weight
per unit area was calculated, and included slab own weight, floor cover, wall loads, beam loads
and live loads. This weight was multiplied by the floor area served by each column, and further
multiplied by 12 stories and by a column own weight factor to obtain the final axial load acting
on each column.
Afterwards, the columns were designed as short columns, as a speedy way to obtain initial
dimensions. At this point, I had successfully completed the execution and verification of the
excel design tool for designing short columns with unknown concrete dimensions. Consequently,
the axial load acting on each column as well as the desired percentage of steel reinforcement in
the cross sectional area of concrete, preferably between 1 – 1.5 %, were inputted into my
spreadsheet to produce the remaining concrete dimension as per the design guidelines of the ECP
203. It is essential to point out that some column dimensions were assigned due to architectural
obligations rather than structural ones. As for core thicknesses, they were chosen as per the
architectural drawings.
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In regard to beams; the breadths were selected to be the same as the underlying wall widths.
There were three different wall widths in the floor plan: 12 cm, 25 cm and 45 cm, and the beam
breadths were assigned accordingly. In addition to this, the beam depths were chosen to be 70 cm
as a normal practice used in Egypt to support carpentry works. Finally, regarding the solid slab
system, slabs were initially distinguished as one way or two way slabs, and then thicknesses
were assigned according to the allowable values shown above following the instructions of the
ECP 203. All of these calculations served as the preliminary proportioning of the structural
elements, before moving on to the detailed design stage.
49
4.4 Typical Floor Modelling Using SAP2000
In order to commence with the design procedures, the straining actions acting on the main
structural elements are required. At this stage we are in need of a structural analysis modelling
package, as SAP2000 (Structural Analysis Program), to obtain the needed straining actions,
deflections and deformations mandatory for design calculations. To begin, I used AutoCAD to
simplify the structural plan into only 3 layers of elements: columns represented by points, beams
represented by lines and slabs represented by closed polylines called “3D frames”. These
polylines were divided into squares of a side length of 0.5 units, or in my case 0.5 meters, as a
mean of refinement to achieve more accurate results for straining actions on the slab. After that,
slabs were removed from areas of voids and the file was then saved under a DXF format in order
to be imported onto SAP2000, and the resulted plan is shown in Figure 4.4.
Figure 4.4: Final AutoCAD file before importing to SAP2000
In order to import the plan onto SAP2000, each structural element had to be linked with the
program’s built in structural templates. In a 2D model, SAP2000 defines columns as joints,
beams as frames and slabs as shells, and so in that respect the AutoCAD layer for each element
was properly linked with its equivalent SAP2000 template. The main objective now was to
obtain a structural model as accurate and realistic as possible. Subsequently, once the plan had
been imported onto the program, a new material for concrete was defined with its essential
properties as weight per unit volume, modulus of elasticity and compressive strength accurately
inputted.
50
Afterwards, load patterns were defined for dead loads as own weight, floor cover, wall and stair
loads, as well as live loads. Then, load combinations for ultimate and working loads were
defined, as well as another case for the ultimate load multiplied by 12 which was used to
simulate the load of the 12 stories on the ground floor columns. After that, concrete section
dimensions, obtained from the preliminary proportioning phase, were defined for slabs and
beams.
From that point, all necessary loads and sections had been defined to the program, and
henceforth these loads and sections were assigned to their respective structural elements. I had
obtained the load assignments for residential buildings as previously referred to from the ECP
201, and so I assigned these values to their correct positions. For further clarification; live loads
were assigned as 3 kN/m2 for stairs, kitchens, bathrooms and balconies, and as 2 kN/m
2 for the
remaining floor area. Also, the floor cover load was considered to be 1.5 kN/m2
for the entire
floor area.
In succession to this, additional loads were calculated manually by hand, where, for instance, the
stair case reaction was obtained and represented as a distributed line load on the core. As for wall
loads; the load for each wall of different thickness was calculated and assigned to its correct
location on the floor plan, and the same was done regarding balcony fences, as demonstrated in
the calculations notebook.
Then, moment releases were assigned to secondary beams to distinguish them from main beams.
Finally, all frame elements of the model, representing beams, were divided at intersections with
their adjacent shell boundaries. This was to carry out a refinement for the model in order to
obtain more accurate results. The final model is shown in Figure 4.5. In that manner, the model
was ready to be run to obtain the desired straining actions to commence with the design
procedures.
Figure 4.5: Completed SAP model for typical floor
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4.5 Design and Detailing of Structural Elements
At this stage, I had the three main factors necessary in order to begin with the design procedures;
a completed SAP model to provide the straining actions on each structural member, the
preliminary dimensions for the structural elements and the spreadsheets required for design.
During this phase, very precise time management was required. I had to ensure that the
spreadsheet used for designing a certain element had been completed and verified prior to
reaching the design phase for that element of the building. This was to avoid any unnecessary
interruptions. I first set out with the design of columns, where the typical floor plan consisted of
58 columns.
4.5.1 Design of Columns
The first step towards the design of a column is identifying it to be a short column or a long
column. This determination initially requires the classification of the building as braced or
unbraced. In that respect, the very first objective was to calculate the moment of inertia of the
cores of the building in both horizontal and vertical directions. Having acquired the moment of
inertia of cores through hand calculations, and along with other requirements; as the building
height, number of floors, floor area and weight per unit floor area, it was concluded that the
building was braced in both horizontal and vertical directions.
Calculations for determining the bracing condition of the building were primarily done manually
by hand calculations. However, at this point I had successfully completed the full execution and
verification of my Excel spreadsheet “Design Tools Package 1: Columns”, and the results of
these calculations were confirmed with the tool concerned with the classification of the building
as braced or unbraced, and in fact turned out to be identical. Afterwards, each column was
investigated to see whether it would be classified as a short or long column, given their position
on the floor plan, clear heights, concrete dimensions and end conditions. As a result, it was
concluded through my Excel spreadsheet that all columns were classified as short columns.
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Throughout the next step, the total values of axial forces for the 12 floors acting on the columns
were obtained from the SAP model, as shown in Figure 4.6, and compared to those obtained
from the area method. It was found that the corresponding values were similar and within the
same range, and any differences were contemplated and reasoned. The SAP model, however,
produces better results, so its values of axial force were taken along with the preliminary
dimensions obtained from the area method, and were fed into my spreadsheet for design of short
columns to obtain final results, following the guidelines of the ECP 203. Dimensions were
modified for certain columns to maintain a steel ratio of 1-1.5% and also to unify and condense
column models as much as possible. The typical floor plan, which consisted of 58 columns, was
ultimately narrowed down to just 7 models of concrete dimensions and steel reinforcement.
Figure 4.6: SAP model showing the reactions of columns and cores to the axial forces imposed
53
4.5.2 Design of Cores
Values for core thicknesses were maintained from the architectural plan, and all that remained
was the steel reinforcement; whether lateral reinforcement represented by stirrups or longitudinal
reinforcement through bars. First of all, concerning lateral reinforcement, the volume of stirrups
was taken as 0.25% of the total core volume, as indicated by the ECP 203. Afterwards, the area
of stirrups per layer was reached, considering there are 5 layers of stirrups within each meter of
height of the core. Finally, a steel bar diameter of 12 mm was decided on for both cores and the
required number of stirrups was obtained for each.
Secondly, regarding longitudinal reinforcement, the area of steel bars was taken as 1% of the
core cross section, to account for the endurance of lateral loads as wind and seismic loads, as
instructed by the ECP 203. For each core, a bar diameter of 22 mm was considered and the
adequate number of steel bars were calculated and distributed along the inner perimeter at equal
spaces of 150 mm. All core design calculations are presented in detail in the calculations sheet.
4.5.3 Preparing Columns and Axes Drawing
After the design of both columns and cores was complete, it was necessary to show sufficient
detailing of these members, as well as showcasing all of these eventual structural drawings
within a final plan. First of all, a columns and axes plan, demonstrated in Figure 4.7, of scale
1:100 was prepared showing only columns, which were drawn with their final dimensions, cores,
axes and dimensions lines indicating the distances of all columns and cores from their nearest
axis in both horizontal and vertical directions.
In addition, all 7 of the column models were positioned in a table, for a more organized
appearance, indicating concrete dimensions and steel reinforcement values, as illustrated in
Figure 4.8. The drawing also shows cross sectional detailing of steel bar reinforcement and
stirrups to a scale of 1:25 for both columns and cores. Last, the drawing includes some remarks
on the top right corner concerning practical in situ implementation guidelines. Figure 4.9 shows
the final columns and axes drawing.
54
Fig
ure
4.7
: C
olu
mn
s a
nd
Ax
es P
lan
55
Figure 4.8: Columns Reinforcement Table
56
Fig
ure
4.9
: Fin
al
Co
lum
ns a
nd
Ax
es D
raw
ing
57
4.5.4 Design of Slabs
At the beginning of the project, I chose to implement a solid slab system rather than a flat slab
system. This choice was mainly because it had more attention to detailing, which would enhance
my technical skills as an engineer. Another reason was due to the fact that the foundation of my
building was to be a raft foundation which would be designed in the same way as a flat slab, so I
chose my typical floor slab system to be a solid slab system in order to have more diversity and
learn about two different types of slab systems instead of one.
Before entering the design process for slabs, one way and two way slabs had to be distinguished
from one another through the rectangularity calculations that had been previously executed
during the preliminary proportioning phase. This was an important point to clarify because it
would affect the pattern of the eventual reinforcement. In addition, certain slabs had to be
checked for deflection, with the help of the deflection values from the SAP model, in order to
emerge with the final values of safe slab thicknesses.
Next, all the needed strips for reinforcement were defined on the floor plan in both horizontal
and vertical directions. Afterwards, the model was run to obtain a bending moment contour
illustration, showing the values of bending moment acting on the slabs in both directions for
every point on the floor area. The horizontal direction for bending moment values is shown in
Figure 4.10. At this point, I had completed the execution and verification of the design tool for
slabs in my second Excel spreadsheet “Design Tools Package 2: Slabs and Beams”. In that
respect, I finally inputted the values of bending moment and slab dimensions for each slab
section into my spreadsheet, and resulted in the final values for steel reinforcement according to
the ECP 203.
Figure 4.10: SAP model showing bending moment contour on slabs in horizontal direction
58
Regarding openings and voids, the additional reinforcement required was calculated to be placed
along the sides of each opening in a condensed manner. Turning to the design of stairs, it was
done initially by hand calculations where the statical system for the stair case was chosen to
extend along its longer direction, and then the loads, comprising of slab own weight, floor cover
and live load, were assigned, and then the bending moment diagram was formed. Then, another
SAP model for the staircase statical system was executed and run, as shown in Figure 4.11, for
verification of the resulted values of bending moment, only to find the same values, thus
confirming the design calculations. Finally, the sections were designed using the same Excel
spreadsheet I had executed for slabs, and values for steel reinforcement were obtained, according
to the ECP 203.
Figure 4.11: Additional SAP model showing values of bending moment for stair system
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4.5.5 Preparing Slab Reinforcement Drawing
After the design of slabs was finalized, the reinforcement was drawn according to the bending
moment values, obtained from the SAP model, for each section of each strip. The pattern and
shapes of reinforcement were conducted following the guidelines of the ECP 203, concerning
positive and negative moment reinforcement lengths and positions within the slab. Adequate
reinforcement shapes were drawn for cantilever slabs and depressed slabs. All of this was put on
a plan of a scale of 1:50. This plan was positioned in the slab reinforcement drawing and shows
the steel reinforcement distribution and shape, as well as the number of bars per meter on the
slab and bar diameter for each. In addition, the drawing indicates positions of depressed slabs
through a sectional cut. The drawing also includes practical remarks for in situ implementation
guidelines. The final slab reinforcement drawing is shown in Figure 4.12.
4.5.6 Preparing Stairs and Openings Reinforcement Drawing
Another drawing was required among the final drawings to show the details of reinforcement of
stairs and openings; as their reinforcement patterns and shapes were dissimilar to other slabs and
had to be given specific detailing attention. The drawing shows the openings drawn to a scale of
1:10 along with the positioning, length and amount of additional steel reinforcement needed on
each side of the opening, as previously calculated. Regarding reinforcement detailing for stairs,
the drawing provides a section view at a scale of 1:25 for the stair case, showing the necessary
shapes, lengths and quantities of steel reinforcement as specified by the ECP 203 guidelines for
stair reinforcement. Similarly, practical implementation remarks are provided on the drawing.
The final stairs and openings reinforcement drawing is shown in Figure 4.13.
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Fig
ure
4.1
2:
Fin
al
Sla
b R
ein
forc
em
en
t D
raw
ing
61
Fig
ure
4.1
3:
Fin
al
Sta
irs a
nd
Op
en
ing
s R
ein
forc
em
en
t D
raw
ing
62
4.5.7 Design of Beams
As mentioned before, beam widths were considered to be the same as the underlying wall widths,
whether 12 cm, 25 cm or 45 cm, and the depth for all beams was chosen to be 70 cm. The SAP
model was run for values of bending moment acting on the beams, as shown in Figure 4.14, and
sections were designed using my Excel spreadsheet “Beams Designed for Moment”. Sections
were designed as T-sections, L-sections or R-sections, depending on the direction of bending
moment acting on the section, whether positive or negative, and on the beam location, whether
an edge beam or an interior beam.
Figure 4.14: SAP model showing values of bending moment on beams
63
In succession to this, the model was run for values of shear force acting on the beams, as
displayed in Figure 4.15, and each beam was checked for shear force additional requirements, in
terms of additional stirrups, given that the minimum value for shear stress was exceed. Finally,
the model was run for a third time, but for values of torsional moment acting on beams, as
demonstrated in Figure 4.16. Beams which were subjected to primary torsion were designed for
torsional moment, determining the required additional shear reinforcement in terms of closed
stirrups, longitudinal bars and additional upper and lower reinforcement. Design of beams for
shear force and torsional moment was completed using my spreadsheets “Check Shear” and
“Check Torsion”.
Figure 4.15: SAP model showing values of shear force on beams
64
Figure 4.16: SAP model showing values of torsional moment on beams
In this manner, each beam had been designed for bending moment, shear force and torsional
moment, and the values of steel reinforcement, whether bars or stirrups, had been acquired
following the limit states of the ECP 203. The last step for this phase was to condense the beam
models as much as possible, by trying to unify beams with similar steel reinforcement patterns,
in terms of number of bars and bar diameter. In the end, the 82 beams in the typical floor were
simplified into 10 models.
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4.5.8 Preparing Beam Reinforcement Drawing
After completing the design of beams due to all the straining actions acting on them, a final
drawing for beam reinforcement detailing was prepared. The drawing includes a plan of scale
1:100 indicating on each beam its model label, from B1 to B10. It also includes a beam
reinforcement table, displaying information for each beam model as its dimensions, steel
reinforcement pattern and additional notes, if required. This beam reinforcement table is shown
in Figure 4.17.
The steel reinforcement pattern is related to a typical beam elevation drawing, also existing in the
final drawing, showing the distribution of steel reinforcement along the length of the beam. This
drawing displays the positions and lengths of upper and lower reinforcement, whether main or
additional, along the beam, as well as the distribution of stirrups in the mid span area and their
densification near the supports.
The beam reinforcement table indicates the values of main and additional reinforcement, for both
upper and lower distributions, as well as the amount of mid span stirrups for each beam model.
The beam reinforcement table along with the typical beam elevation drawings presents all the
necessary information for steel reinforcement distribution within the beams. Also, the notes
column in the table indicates necessary reinforcement remarks additional to those displayed by
the typical beam drawing.
Last, the drawing comprises of an area dedicated to further reinforcement detailing for beams
with special reinforcement patterns, as the four bent beams on the four corners of the plan.
Sufficient reinforcement detailing is provided, along with cross sectional drawings for several
beams in need of further clarification. Finally, similar to the rest of the drawings, the beam
reinforcement drawing includes a section for practical implementation remarks. The final
drawing is demonstrated in Figure 4.18.
Figure 4.17: Beam Reinforcement Table
66
Fig
ure
4.1
8:
Fin
al B
eam
Re
info
rce
me
nt
Dra
win
g
67
4.5.9 Design of Raft Foundation
My building is a midrise building consisting of 12 stories. Therefore, a reinforced concrete raft
foundation was the most suitable type of foundation to implement, as it would be a more
preferable solution to isolated footings in this case. First of all, the raft outer dimensions were
taken as 34.45 x 25.85 meters; the same as the building boundaries. Also, the raft thickness was
considered to be 1.2 meters as an initial proportioning. This was reached through appointing 10
cm of raft thickness to each floor the building rises. In this case, the building consisted of 12
floors, resulting in the assigning of 1.2 meters of raft thickness. In addition to this, a layer of
plain concrete of 20 cm of thickness was assigned to be placed below the reinforced concrete raft,
and the foundation level was set to be at 1.6 meters below the natural ground level.
The underlying soil layers were precisely compacted in order to reach a bearing capacity of 200
kN/m2. Such a bearing capacity is a well needed requirement to support midrise buildings of 12
stories. For the next step, the raft was checked against global stress, by verifying that all the
loads acting on its proposed area produced a stress less than the soil bearing capacity of 200
kN/m2. And indeed, the stresses acting on the raft emerged to be 178.82 kN/m
2, confirming the
validity of the preliminary dimension proportioning, and granting a green light to proceed with
the remaining procedures.
Consequently, I constructed a new SAP model for the raft foundation with the stated dimensions
and thickness. Load combination cases for both working and ultimate loads were defined. Then,
joint springs were allocated at the joints between the shells representing the raft, and spring
stiffnesses were calculated and assigned for intermediate, edge and corner springs relative to the
raft boundaries. These springs produce reactions which collectively simulate the effect of the soil
resistance to the building loads. The springs are demonstrated in Figure 4.19.
Figure 4.19: SAP model showing springs for raft foundation
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Next, I used my original typical floor SAP model to obtain the forces acting on each ground floor
column resulting from the loads of the 12 floors of the building, and assigned them as
concentrated loads to their corresponding locations on the raft, as shown in Figure 4.20. These
forces, however, were obtained due to the working load combinations of the building, rather than
the ultimate, in order to check the stresses induced on the soil before proceeding with the design
of the raft itself. This way, I had a SAP model for the raft foundation, with springs representing
the underlying soil with the existing bearing capacity and concentrated forces simulating the
entire loads of the building. The model was run and local stresses acting on each spring were
checked, and found to be safe as well. Through the validity of both global and local stress values;
this meant that this raft with the proposed dimensions, along with the soil state and bearing
capacity, were adequate to bear the forces posed from the entire building. At this juncture, I was
in a suitable position to begin with the design operations of the raft foundation and obtain the
sufficient quantities of steel reinforcement.
Figure 4.20: SAP model showing concentrated loads on raft to represent the whole building
69
In that respect, the model was run due to the ultimate case of loading to produce a contour for the
values of bending moment acting on the raft in both horizontal and vertical directions. The
bending moment contour for the horizontal direction is demonstrated in Figure 4.21. Unlike slabs,
values of positive bending moment in the raft were produced underneath locations of columns,
while values of negative bending moment were found in areas free of columns. The raft was
designed in the same manner as a flat slab, and a starting upper and lower mesh of 5 22 per
meter was assigned, based on the value of minimum steel area for the raft cross section (As min).
The maximum resistance of this reinforcement web was determined, and then the SAP model
was used to find the areas on the raft with higher bending moment values, for appointing
amounts of additional reinforcement. Finally, the required additional reinforcement for each area
was calculated using my Excel spreadsheet “Slabs”.
Figure 4.21: SAP model showing bending moment contour on raft in horizontal direction
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4.5.10 Preparing Raft Foundation Drawing
After defining the values of additional steel reinforcement required for the raft, it was necessary
to perform the adequate detailing. A raft foundation drawing was prepared containing a plan of
the raft to a scale of 1:50 showing its boundaries along with the locations of the columns and
cores. On this plan, the raft thickness is indicated along with the reinforcement value for the
starting upper and lower mesh. In succession to this, the necessary additional reinforcement bars
for both directions were drawn at their respective positions, with bar lengths, shapes and
distribution distances calculated and indicated as per the guidelines of the ECP 203. Moreover,
stair starters are shown on the drawing. Last, the plan contains a section for practical
implementation remarks, in similar fashion to the rest of the drawings. The final raft foundation
drawing is shown in Figure 4.22.
71
Fig
ure
4.2
2:
Fin
al R
aft
Fo
un
dati
on
Dra
win
g
72
4.6 Quantity Estimation and Cost Analysis
At this point in time, I had successfully completed the implementation of my midrise reinforced
concrete building from start to end. All the phases had been finalized; beginning with preparing
the architectural plan, then moving on to selecting the statical system and performing preliminary
proportioning of the elements, to preparing a SAP model, and ending with the design of all
structural elements and producing the required structural drawings with elaborate reinforcement
detailing. The final phase of the project was to carry out quantity estimation and cost analysis
investigations and prepare a bill of quantities for the building material used. This was an optional
task in my project description and was not one of the main deliverables. However, I was keen on
creating some additional time space in my schedule for this task, as I saw it as a highly
significant closure phase to the project.
Firstly, regarding the quantity estimation inspections; the aim was to acquire the amount of
fundamental building material used for the construction of the 12 story midrise building as per
the design requirements. Fundamental building material refers to concrete and steel
reinforcement, including both bars and stirrups for some elements. In that respect, quantities of
concrete volumes, in cubic meters, and steel reinforcement, in tons, were calculated for each
structural element; the raft foundation, columns, cores, slabs and beams. These deductions were
obtained mostly through hand calculations, while some were carried out using Excel
spreadsheets for calculating concrete and steel quantities, given to me during my regular
meetings with the thesis supervisor (Notes, 2014).
73
After finishing the required calculations, I performed some additional expansions to the Excel
spreadsheets I was provided with, to conclude the calculations for each element with the sums of
quantities of concrete and steel. I also proceeded with some modifications to the style and
appearance of the sheet to make it more appealing to viewers. As a demonstration for one of
these spreadsheets, the spreadsheet used for determining quantities for columns is exhibited in
Figure 4.23 (Notes, 2014). In addition to this, values of earthwork for cutting and filling were
calculated and are included in the bill of quantities.
NO H cm L cm B cm Bars mm Bars No. Stirrups mm Stirrups @ cm Stirrups leg NO Concrete M³ Bars Ton Stirrups Ton
C1 3720 60 25 12 66.96 0.00 #DIV/0!
C2 3720 80 25 14 104.16 0.00 #DIV/0!
C3 3720 100 25 8 74.40 0.00 #DIV/0!
C4 3720 120 25 8 89.28 0.00 #DIV/0!
C5 3720 130 30 12 174.10 0.00 #DIV/0!
C6 3720 80 45 2 26.78 0.00 #DIV/0!
C7 3720 110 45 2 36.83 0.00 #DIV/0!
572.51
C1 420 12 12 12 0.00 0.70 #DIV/0!
C1 300 12 12 132 0.00 6.01 #DIV/0!
C2 420 16 12 14 0.00 1.45 #DIV/0!
C2 300 16 12 154 0.00 12.47 #DIV/0!
C3 420 16 16 8 0.00 1.11 #DIV/0!
C3 300 16 16 88 0.00 9.50 #DIV/0!
C4 420 18 18 8 0.00 1.57 #DIV/0!
C4 300 18 18 88 0.00 13.53 #DIV/0!
C5 420 16 18 12 0.00 1.87 #DIV/0!
C5 300 16 18 132 0.00 16.04 #DIV/0!
C6 420 20 14 2 0.00 0.38 #DIV/0!
C6 300 20 14 22 0.00 3.25 #DIV/0!
C7 420 18 18 2 0.00 0.39 #DIV/0!
C7 300 18 18 22 0.00 3.38 #DIV/0!
71.66
Input Data Results
Concrete
Longitudinal Bars
BacBac
Figure 4.23: Spreadsheet for determining concrete and steel quantities for columns
74
One of the main objectives of quantity estimation is to emerge with the final reinforcement ratio
for each element. The reinforcement ratio is the amount of steel reinforcement within the
concrete volume, in units of kg/m3. In that regard, after the completion of all quantity estimation
calculations, I prepared a separate Excel sheet displaying the final volumes for concrete and steel
for each structural member along with the corresponding reinforcement ratio. All results were
found to be within the range of reinforcement ratios used nowadays in practice, which
emphasizes on the efficiency of all my previous work throughout the project. The final
reinforcement ratios are demonstrated in Table 4.1.
Table 4.1: Reinforcement Ratios for Structural Elements
Element Total Concrete Volume (m3)
Total Steel Weight (tons)
Rft Ratio (kg/m3)
Columns 572.52 93.66 163.59
Cores 1062.4 171.55 161.47
Slabs 1064.8 90.34 84.84
Beams 744.5 68.6 92.14
Slabs + Beams 1809.3 158.94 87.85
Raft Foundation 1068.64 77.891 72.89
Total 4512.86 502.041 111.25
75
Concerning cost analysis, I acquired the current rates for steel, concrete components and both
cutting and filling of soil, all from an actual engineer in practice of personal acquaintance
(Mohamed, 2014). The values for cutting and filling were of the specific type of soil used in my
project according to my site specifications, where the soil I used had a bearing capacity of 200
kN/m3 and had been compacted in several layers.
Regarding concrete, I obtained the components of both plain concrete and reinforced concrete, of
a 30 MPa compressive strength, through a materials engineer working in practice (Yehia, 2014).
The final prices for both types of concrete were achieved after derived calculations, according to
the mixture components of each and their respective prices. It is essential to point out that all
acquired rates are up-to-date and are according to the current market conditions and prices in
Egypt. All the performed calculations are present in my calculations notebook, and the final
prices for the components used in the project are as follows:
Cost of soil cutting = 30 EGP/m3
Cost of soil filling = 40 EGP/m3
Cost of steel = 5500 EGP/ton
Cost of Plain Concrete = 344.5 EGP/m3
Cost of Reinforced Concrete (fcu = 30 MPa) = 450.75 EGP/m3
Finally I executed another Excel sheet for the bill of quantities consisting of headings for each
structural element and subheadings for the related materials of concrete and steel, all according
to the logical order of practical execution. The bill of quantities, shown in Table 4.2, also
indicates units, unit rates and the final costs for each material. Finally it shows the total cost of
materials required for the implementation of this project, and it emerged to be 4,910,470.27
Egyptian Pounds. Certain calculations for quantity estimation and cost analysis can be found
within Appendix B, for further elaboration.
76
Table 4.2: Bill of Quantities for the Project
Item Description Quantity Unit Rate Amount (EGP)
1 Earth Works
1.1 Cutting 1463.7 m3 30 43,911.00
1.2 Filling 203.31 m3 40 8,132.40
52,043.40
2 Raft Foundation
2.1 Plain Concrete 182.96 m3 344.5 63,029.72
2.2 Reinforced Concrete 1068.64 m3 450.75 481,689.48
2.3 Steel Reinforcement Bars 68.701 tons 5500 377,855.50
2.4 Steel Starters 9.19 tons 5500 50,545.00
973,119.70
3 Cores
3.1 Concrete 1062.4 m3 450.75 478,876.80
3.2 Longitudinal Bars 126.23 tons 5500 694,265.00
3.3 Stirrups 45.32 tons 5500 249,260.00
1,422,401.80
4 Columns
4.1 Concrete 572.52 m3 450.75 258,063.39
4.2 Longitudinal Bars 71.66 tons 5500 394,130.00
4.3 Stirrups 22 tons 5500 121,000.00
773,193.39
5 Slabs
5.1 Concrete 1064.8 m3 450.75 479,958.60
5.2 Steel Reinforcement Bars 90.34 tons 5500 496,870.00
976,828.60
6 Beams
6.1 Concrete 744.5 m3 450.75 335,583.38
6.2 Steel Reinforcement Bars 45 tons 5500 247,500.00
6.3 Stirrups 23.6 tons 5500 129,800.00
712,883.38
Total 4,910,470.27
77
Chapter 5
Conclusion
As the curtain unfolds and the project comes to an end, it can be said that all the project
deliverables have been successfully completed and presented. It is also necessary to highlight
that the gained assets on a personal level are of much greater magnitude than I had initially
anticipated. Regarding the design spreadsheets task, the final products are a set of 7 Excel
spreadsheets comprising of 19 structural design tools executed on the highest levels of technical
accuracy and appeal to users. In addition, verifications for the precision of the produced results
from the spreadsheet are present. As for the midrise building task, the final outputs are all the
structural drawings required for accurate representation of the building structural elements and
reinforcement detailing, performed to the highest level of quality and structural precision. All
analytical models and design spreadsheets used are also available. Another product is an actual
bill of quantities with the amounts and costs of the materials required for the erection of the
building.
On a personal level, an irreplaceable amount of knowledge and experience has been gained
throughout the duration of the project. For instance, in order to develop the design spreadsheets, I
conducted thorough studies concerning the design of different structural members with all their
possible cases, and this was of exceptional benefit to me on an academic level. Moreover, on a
practical level, the experience of completing a structural design project from start to end, passing
by all its phases and complications, has greatly enhanced my insights as a future engineer.
Another major benefit I came out with from the project was the competence I gained in using
structural design related softwares as AutoCAD, SAP 2000 and Microsoft Excel. All of these
aspects have given me a feeling of fulfillment and self-confidence towards implementing any
type of structural design I may face in the future. Furthermore, after conducting quantity
estimation and cost analysis investigations, along with preparing an actual bill of quantities, it
was of great content and satisfaction for me to witness all the hard work of the previous months
being translated into actual values of materials and prices, and this also provided me with a better
engineering vision for future work.
78
Among the many benefits, the best aspect of this project, for me, was the experience of going
through an independent cycle of work. I actually built my design tools from scratch and then
practically put them to further use to implement an actual end product. This to me was inspiring
because it meant that every single progression I had made throughout the project ending with the
final structural drawings were all a product of my initial efforts, without the use of any external
helplines. One last benefit that needs to be emphasized is the improved sense of time
management that I gained, and the appreciation of time efficiency that I acquired from
performing the numerous tasks of this project all simultaneously. To conclude, I cannot iterate
enough on how productive this experience has been for me. I will always be grateful for being
allowed the opportunity to embark on such a project and work with my supervisor, as his
incomparable guidance has without a doubt, expanded my horizons as an engineer to much
greater extents.
79
References
Allison Architecture (2011). Planning Application Submitted for Newton Mearns Project.
Retrieved May 28, 2014, from http://www.allisonarchitecture.co.uk/
Boeing Consulting (2014). Loads on Buildings. Retrieved May 29, 2014, from
http://www.boeingconsult.com/
Computers and Engineers (2003). SAP2000 Integrated Software for Structural Analysis and
Design. Retrieved May 30, 2014, from http://www.comp-engineering.com/index.htm
Education Portal (2014). CAD Drafting and Design Technology. Retrieved May 30, 2014,
from http://education-portal.com/
El-Leathy, Y. (2013). Handouts for Design of Reinforced Concrete Structures Courses, GUC.
Ghoneim, M. A., & El-Mihilmy, M. T. (2008). Design of Reinforced Concrete Structures
Volume 1.
Harvey, G. (2006). Excel 2007 Workbook for Dummies. Wiley Publishing, Inc.
Helal, K. (2012). Course Notes of Design of Reinforced Concrete Structures I, GUC.
Mohamed, A. (2014). Personal Contact.
Moroni, M. O. (2011). Concrete Shear Wall Construction.
Notes (2014). Bachelor Thesis, GUC.
Permanent Committee for ECP-201 (2012). Egyptian Code for Calculating Loads and Forces
in Structural Work and Masonry. Egypt, Giza: National Research Center for Housing and
Building.
Permanent Committee for ECP-203 (2007). Egyptian Code for Design and Construction of
Reinforced Concrete Structures. Egypt, Giza: National Research Center for Housing and
Building.
Richard, M. J. (2009). Parametric Study of ACI Seismic Design Provisions Through
Dynamic Analysis of a Reinforced Concrete Intermediate Moment Frame.
The Constructor (2012). High Rise Structures. Retrieved May 30, 2014, from
http://theconstructor.org/
Yehia, M. (2014). Personal Contact.
80
Appendix A
Verification Examples for Excel Design
Spreadsheets
81
82
12 floors
37 meters
17.6 kN/m2
881.6 m2
N (kN) in X-
Direction
in Y-
Direction
Condition in Y-
Direction
186193.92 0.52 0.26 Braced
Building is Braced
Braced
Total Moment of Inertia of Shear Walls in X-direction
(Iy)39.3678
Number of Building Floors Including Ground Floor
General Building Information
Condition in X- Direction
m4
Total Moment of Inertia of Shear Walls in Y-direction
(Ix)151.74 m4
Total Floor Area
Average weight of 1 m2 of floor
Building Height
CLASSIFICATION OF BUILDING AS
BRACED OR UNBRACED
TOOL 1
83
84
85
800
6.3
1.2
0.7
6.5
1.2
0.35
b Out of
Planeb max Buckling Plane
22.29 22.29 b Plane
b 0.087 m
Madd = 69.53 kN.m
Normal Force
b In Plane
10.80
Conclusion
Long Column
meters
t
Column Clear Height
K Buckling
b
Column Clear Height
K Buckling
If Rectangular Column
kN
t Plane
meters
meters
b Plane
meters
CLASSIFICATION OF RECTANGULAR
COLUMN AS SHORT OR LONG COLUMN
TOOL 2
86
87
b (mm) t (mm)
C1 3700 i 450 1100 495000 4 0.6 -0.529 N/A 16
C2 3700 i 450 700 315000 4 0.6 1.242 N/A 16
C3 3700 i 450 450 202500 4 0.6 3.948 N/A 18
DESIGN OF RECTANGULAR COLUMN WITH KNOWN CONCRETE DIMENSIONS
TOOl 4
Column DimensionsComment
Reinforcement
Enter bar
diameter (mm)
no. of steel
bars
min
(%)As required (mm2)
Minimum As required (SAFE)
Normal proceedings (SAFE)
Normal proceedings (SAFE)
2970.00
3912.73
7993.88
Column actual
(%)
Ultimate Load
(kN)Ac (mm2)
Required Ac to be
reached (mm2)
Column
Position
(i,e,c)
max
(%)
16
18
25
88
89
C1 4640 1 415696.11 300 1400 4156.96 18 18
ColumnUltimate Load
(kN)
Desrired μ
(%)As required (mm2)Ac (mm2)
Reinforcement
no. of steel bars
Comment
Column Dimensions
b (mm)
safe
Enter Steel bar
diameter (mm)t (mm)
PROPORTIONING AND DESIGN OF RECTANGULAR COLUMN WITH UNKNOWN
CONCRETE DIMENSIONS
TOOL 6
C1 4640 1 415696.11 18 18
TOOL 7
PROPORTIONING AND DESIGN OF SQUARE COLUMN WITH UNKNOWN
CONCRETE DIMENSIONS
b (mm)
650 4156.96
ColumnUltimate Load
(kN)
Desrired μ
(%)Ac (mm2)
Column Dimensions
As required (mm2)no. of steel bars
Reinforcement
Enter Steel bar
diameter (mm)
C1 4640 1 415696.11 18 18
PROPORTIONING AND DESIGN OF CIRCULAR COLUMN WITH UNKNOWN
CONCRETE DIMENSIONS
TOOL 8
D (mm)Enter Steel bar
diameter (mm)no. of steel bars
750 4156.96
ColumnUltimate Load
(kN)
Desrired μ
(%)Ac (mm2)
Column Dimensions
As required (mm2)
Reinforcement
90
1 21.8 1000 140 4.74 0.824 427.78 524.73
2 12.46 1000 140 6.27 0.826 389.09 389.09
TOOL 9
DESIGN OF SLABS WITH KNOWN THICKNESS
Section
Ultimate
Moment
(kNm)
Breadth
b (mm)
Depth d
(mm)C1 J
As min
(mm2)
As used
(mm2)Comment
Reinforcement
Enter bar diameter
(mm)no. of steel bars
Normal Proceedings (safe) 10 7
As < As min, As min used (safe) 10 5
91
92
93
1 110.8 250 3.5 0.782 500 381.94 845.01
no. of steel bars
5
Reinforcement
Enter bar diameter
(mm)
16
Comment
Normal Proceedings (safe)
C1Breadth
b (mm)
Ultimate
Moment (kNm)Section
As used
(mm2)
As min
(mm2)
Depth d
(mm)J
TOOL 11
PROPORTIONING AND DESIGN OF RECTANGULAR SECTION WITH
UNKNOWN CONCRETE DIMENSIONS
max no. of
bars in row
no. of rows
requiredAs used
As stirrup
hangers
no. of
shrinkage bar
rows
5 1 845.01 169.00 2 ϕ 12 none - ϕ - -
As main Stirrup Hangers Shrinkage Bars
Stirrup Hangers Rft. Quantity per row
Spacing
between
rows (mm)
TOOL 15
FURTHER REINFORCEMENT NOTES
94
1 41.56 250 500 6.13 0.826 363.38 363.38
SectionUltimate
Moment (kNm)
Breadth
b (mm)C1 J
Depth d
(mm)
As < As min, As min used (safe)
CommentAs min
(mm2)
As used
(mm2)
TOOL 10
DESIGN OF RECTANGULAR SECTION WITH KNOWN CONCRETE
DIMENSIONS
no. of steel bars
2
Reinforcement
Enter bar diameter
(mm)
16
max no. of
bars in row
no. of rows
requiredAs used
As stirrup
hangers
no. of
shrinkage bar
rows
5 1 363.38 72.68 2 ϕ 10 none - ϕ - -
As main Stirrup Hangers
Stirrup Hangers Rft. Quantity per row
Spacing
between
rows (mm)
Shrinkage Bars
TOOL 14
FURTHER REINFORCEMENT NOTES
95
1 90.68 250 1050 500 8.51 0.826 381.94 609.90
SectionUltimate
Moment (kNm)
Breadth
b (mm)
Depth d
(mm)C1
Reinforcement
Enter bar diameter
(mm)
no. of steel
bars
Normal Proceedings (safe) 16 4
TOOL 12
DESIGN OF T OR L SECTION WITH KNOWN CONCRETE DIMENSIONS
Comp.
Flange B
(mm)
JAs min
(mm2)
As used
(mm2)Comment
max no. of
bars in row
no. of rows
requiredAs used
As stirrup
hangers
no. of
shrinkage bar
rows
5 1 609.90 121.98 2 ϕ 10 none - ϕ - -
Shrinkage Bars
Stirrup Hangers Rft. Quantity per row
Spacing
between
rows (mm)
TOOL 16
FURTHER REINFORCEMENT NOTES
As main Stirrup Hangers
96
97
98
28
210
48
410
Beam
Shea
r For
ce Q
(kN)
Brea
dth b
(mm)
Dept
h d
(mm)
q cu
(N/m
m2 )
q u
(N/m
m2 )
q u max
(N/m
m2 )n
ϕ (mm)
Spac
ing S
(mm)
125
0.25
250
550
0.98
1.82
2.86
48
126.1
98
ϕ8
4br
anch
es
210
025
055
00.9
80.7
32.8
62
8N/
A5
ϕ8
2br
anch
es
322
040
055
00.9
81.0
02.8
64
820
5.65
5ϕ
84
bran
ches
nϕ
= stir
rup s
teel
diame
ter (
mm)
n = nu
mber
of st
irrup
bran
ches
1 2 3
Assu
mptio
n
numb
er
Orde
r of a
ssump
tions
for n
and ϕ
ϕ
Furth
er Co
mmen
t
If b >=
400,
take t
he in
itial
assu
mptio
n of n
= 4
If b <
400,
take t
he in
itial
assu
mptio
n of n
= 2
qcu <
qu <
qu m
ax, P
roce
ed fo
r She
ar Rf
t. Calc
ulatio
ns
Comm
ent
4
qu <
qcu,
Use 5
ϕ 8/
m
qcu <
qu <
qu m
ax, P
roce
ed fo
r She
ar Rf
t. Calc
ulatio
ns
100 <
S < 2
00 (S
AFE)
TOOL
18
CHEC
K SHE
AR ST
RESS
FOR B
EAM
S
N/A
S > 20
0, Us
e 5 ϕ
8 (SA
FE)
Shea
r Rein
force
ment
99
100
101
8
10
12
2
1
3
TOOL 19
CHECK TORSIONAL MOMENT FOR BEAMS
The vertical distance between longitudinal bars must not exceed 300mm
The minimum steel diameter for longitudinal bars is 12 mm
ϕ = stirrup steel diameter (mm)
Assumption number ϕ
Order of assumptions for ϕ
ϕ
(mm)
Spacing S
(mm)
1 50 300 900 0.24 1.43 2.86 8 75.79 - ϕ - - branches
2 50 300 900 0.24 1.43 2.86 10 118.42 9 ϕ 10 2 branches
3 8 300 900 0.24 0.23 2.86 8 N/A 5 ϕ 8 2 branches
4 15 300 900 0.24 0.43 2.86 8 252.64 5 ϕ 8 2 branches
Further Comment
qu max
(N/mm2)CommentBeam
Torsional
Moment
Mtu
(kNm)
Breadth b
(mm)
Thickness
t (mm)
qt min
(N/mm2)
qtu
(N/mm2)
S > 200, Use 5 ϕ 8 (SAFE)
S < 100, Try another assumption of ϕ (UNSAFE)
100 < S < 200 (SAFE)
N/A
Closed Stirrups
qt min < qtu < qu max, Proceed for Torsional Design
Reinforcement
qt min < qtu < qu max, Proceed for Torsional Design
qt min < qtu < qu max, Proceed for Torsional Design
qtu < qt min, Use 5 ϕ 8/m
AsLB (mm2)AsLB min
(mm2)
AsLB used
(mm2)
AsLB/4
(mm2)
Enter bar
diameter
no. of
steel
bars
N/A N/A N/A N/A 16 N/A
972.70 435.75 972.70 243.18 16 2
N/A N/A N/A N/A 12 N/A
291.81 1116.65 1116.65 279.16 16 2
Longitudinal Bars
102
Appendix B
Quantity Estimation and Cost Analysis
Calculations
103
104
105
106
107
108
NO H cm L cm B cm Bars mm Bars No. Stirrups mm Stirrups @ cm Stirrups leg NO Concrete M³ Bars Ton Stirrups Ton
C1 3720 60 25 12 66.96 0.00 #DIV/0!
C2 3720 80 25 14 104.16 0.00 #DIV/0!
C3 3720 100 25 8 74.40 0.00 #DIV/0!
C4 3720 120 25 8 89.28 0.00 #DIV/0!
C5 3720 130 30 12 174.10 0.00 #DIV/0!
C6 3720 80 45 2 26.78 0.00 #DIV/0!
C7 3720 110 45 2 36.83 0.00 #DIV/0!
572.51
C1 420 12 12 12 0.00 0.70 #DIV/0!
C1 300 12 12 132 0.00 6.01 #DIV/0!
C2 420 16 12 14 0.00 1.45 #DIV/0!
C2 300 16 12 154 0.00 12.47 #DIV/0!
C3 420 16 16 8 0.00 1.11 #DIV/0!
C3 300 16 16 88 0.00 9.50 #DIV/0!
C4 420 18 18 8 0.00 1.57 #DIV/0!
C4 300 18 18 88 0.00 13.53 #DIV/0!
C5 420 16 18 12 0.00 1.87 #DIV/0!
C5 300 16 18 132 0.00 16.04 #DIV/0!
C6 420 20 14 2 0.00 0.38 #DIV/0!
C6 300 20 14 22 0.00 3.25 #DIV/0!
C7 420 18 18 2 0.00 0.39 #DIV/0!
C7 300 18 18 22 0.00 3.38 #DIV/0!
71.66
Input Data Results
Concrete
Longitudinal Bars
BacBac
109
110
111
