Advanced Structural Design

Industrial/Office Building Capstone Design Project 1

Group 3: Kevin Gabrielson, Nick Knepp, Chris Lazration, Kyle Terry

Spring 2014

Table of Contents

Section page number

1. Introduction and Problem Statement............................................................................2

2. Basic Load Determination..............................................................................................3

3. Conceptual Design Development...................................................................................7

4. Main Wind Force Resisting System and Component Cladding.....................................11

5. Composite Office Area Floor Framing Design...............................................................14

6. Snow Loading and Roof Framing Design......................................................................17

7. Column Design.............................................................................................................22

8. Foundation Analysis and Design...................................................................................24

9. Crane Channel and WF Combination Girder Analysis and Design................................26

10. Additional Design Beyond Minimum Requirements – Base Plate Design...................28

11. Final Engineering Plans, Sections, Elevations and Details...........................................30

12. Overall Summary and Conclusions.............................................................................32

1

Introduction and Problem Statement

This urban renewal project calls for the replacement of the abandoned Hudson Motors

Plant with a new, state-of-the-art facility by Nissan Motor Co., LTD. The property is located at

the corner of Beaufait Street and Mack Avenue in Detroit, Michigan. The deal stipulates a 100

year lease of the property, the demolition of the existing plant, the construction of an

engineering and manufacturing facility that fabricates parts for electric powered vehicles, and

that the facility’s lights be powered by solar roof panels. The need for both engineering and

manufacturing space requires the facility be separated into 3 areas: a multistory office space

(15,000 ± 800 sq.ft.), a dedicated manufacturing area (55,000 ± 2,000 sq.ft.), and a material

handling (shipping/receiving) area with an overhead crane (18,000 ± 1,000 sq.ft.). Each one of

these areas has unique requirements to adhere to.

The design specifications used for the design and analysis are the ASCE/SEI 7-10

Minimum Design Loads for Buildings and Other Structures, ACI 318-11, and the AISC Steel

Construction Manual. The materials used for the design thus far are primarily A992 structural

steel (for columns, beams, and girders) and concrete. Other materials will be needed for

insulation, the façade (brick and panels), windows (glass), etc.

The initial submittal called for determination of loads and a conceptual design. This

expanded one includes the lateral force resisting system and the composite office area floor

framing design and the snow loading, roof framing plan, and column design. Before these

systems could be designed a number of corrections had to be made, primarily to the loads,

beam estimations, and height of the facility’s areas. The MWFRS was redesigned.

2

3

Basic Load Determination

This section contains the basic loads and an explanation for how these loads were

determined. Various websites were used in finding specific materials loads such as, metal deck,

roofing dead load, and solar panel array. Below is a table with the tabulated loads that are

present on the structure. The facility was determined to fit risk category II.

Manufacturing/Shipping

Roof LoadsDead

Roofing Materials (Engineeringmaterials.com) 5.60 psfSolar Panels (http://www.civicsolar.com/resource/how-much-load-does-solar-array-add-roof 4.00 psfMechanical/Electrical 15.00 psfInsulation (fireonebpco.com) 2.41 psfMetal Decking Type 3N, 20 Gauge (Vulcraft.com) 2.71 psfStructural Steel Framing 5.60 psfHVAC (3) 20 kip each 500.00 plf per edgeTotal Roof Dead (No HVAC) 35.32 psf

Snow (roof) Load 30.00 psfRoof Live Load 20.00 psfWind Load 115.00 mphWall LoadsDead

Insulated Metal Siding 3.60 psfSag Rods 1.043 plfWind Girts 11.50 plf

Wind Load 115.00 mphCrane LoadsLive Load- Wheels

40.00 tons

Table 1: Loads present on the Manufacturing and Shipping areas.

4

Office

RoofDead

Roofing Materials (Engineeringmaterials.com) 5.60 psfSolar Panels(http://www.civicsolar.com/resource/how-much-load-does-solar-array-add-roof) 4.00 psfMechanical/Electrical 4.00 psfInsulation (fireonebpco.com) 2.41 psfStructural Steel Framing 5.80 psfMetal Decking 3N, 20 Gauge (Vulcraft.com) 2.71 psf HVAC (1) 500.00 plfTotal Roof Dead (no HVAC) 24.52 psf

Snow Load (See Text) 30.00 psfRoof Live Load 20.00 psf2nd FloorDead

Carpet 2.00 psfConcrete Slab 45.00 psfComposite Metal Deck 3VLI, Gauge 20, 5" thick (Vulcract.com) 2.14 psfStructural Steel Framing 7.30 psfCeiling 3.00 psfMechanical/Electrical 3.00 psfTotal 2nd Floor Dead 62.44 psf

Live Load (ASCE7) 80.00 psfWall LoadsBrick wall, studs, insulation, and drywall 50.00 psfWind Load (Lateral) 115.00 mph

Table 2: Loads present on the Office Roof and Second Floor.

5

Summary of Load

These loads were determined from the project description, which was given, and others

were determined using websites and calculations. The dead loads were primarily given in the

description. The metal deck load, solar panel load, roof materials load, siding loads, and

insulation load were obtained from various resources. The structural framing loads were

determined by the team and are a hypothesis on what the beams/girders weights will be. The

wind and roof live load were obtained from ASCE 7. The snow load was given by the Building

Official of Detroit as 30psf. The Live Crane Load was given in the project description and is a 40

ton wheel load.

The roofing material atop the entire structure will consist of a felt, tar and gravel roofing

(5.3psf), and a 30 pound paper (0.3psf) (Engineeringmaterials.com). Decking material across

the entire roof of the structure will be a Type 3N, 20 gauge, and galvanized metal deck

(Vulcraft.com). The deck is 3” thick with an allowable span, with 3 spans present, of 15’-6” and

a weight of 2.71psf. The metal decking used on the office floor will be a composite section with

using 3VLI Gauge 20 decking material and 2” of concrete. The concrete slab weights 57psf. The

deck is 3” thick with an allowable span, with 3 spans present, of 12’-3” and a weight of 2.14psf.

The insulation along the entire roof of the structure will be ISOGARD HD Cover Board

(fireonebpco.com). These insulation boards are produced in sheets of 4’ wide x 8’ long x ½”

thick, weighting 11 lbs total (.344psf). The building will consist of a 3 ½” thick insulation board

so the total weight for insulation will be 2.41psf. The solar panel weight was determined from

http://www.civicsolar.com/resource/how-much-load-does-solar-array-add-roof and is 4psf.

The metal siding is 3.60 psf (weight found at

6

http://www.centriaperformance.com/products/wall/architectural_insulated_metal_panel_systems/

formawall_dimension_series/vert_pro/ds60_3_t.aspx). A 5/8” sag rod is 1.05 plf as specified at

(http://www.bgmfg.com/bar_weights.htm). Wind girt weight is specified in AISC from the

section picked in the components and cladding section. The HVAC units are a total weight of

20,000 lbs but are supported along the 20’ edge, producing a 500plf load along the edge. The

office siding will consist of 4” clay brick, studs, insulation, and drywall weighing 50psf.

The structural steel framing loads were determined by using the roof loads to estimate

and size beams, girders, and trusses. The load combinations applied are calculated in an

attached spreadsheet. The manufacturing area had 5.0 psf for structural steel framing, and the

shipping area had 5.30 psf. The shipping number is taken for both and increased to 5.60 psf to

account for heavier beams and girders under the HVAC and keep the roof loads identical. The

office roof load was increased to 5.8 psf from the 5.6 psf calculation.

7

Conceptual Design Development

The conceptual design of the facility involved adhering to all design parameters while

trying to make the facility safe, free flowing, easy to construct, and economical. A lot of early

designs and ideas were considered until the design shown below was decided on. This design

was determined to best meet all of the requirements and goals for the project.

The initial process was to brainstorm and develop basic schemes based on the

information provided for the project. Once a number of schemes were considered, the owner

requirements and the criteria mentioned above were used to evaluate the schemes. Then

schemes judged as non-ideal were rejected, but desirable traits from them were incorporated

into the chosen design. This design was continuously evaluated and altered as it developed.

An example of a rejected scheme was one in which the shipping area was parallel to

Mack Ave. The design had the facility against the northwest edge of the lot with open space

below. This design was scrapped because it limited truck maneuverability and forced the

people entering and exiting the office to cross in front of or behind the material handling bays

(where the trucks pass through).

8

Summary

The design process for the facility started with basic conceptual ideas such as where

each area should go, how they should be oriented, etc. Utilizing the space of the lot was the

first important design criteria. After that, the details of each area of the facility could be

determined. The lot contains much more area than needed for the facility, but this excess space

is needed to allow trucks to maneuver into and out of the shipping area. Gates were set up at

the northeast and northwest corners of the lot to allow trucks in. The trucks drive through the

entrance of the shipping area on the north side of the building and then out through the

opposite side of the area and exit the property through the south gate. The material handling

area had to be a long rectangle due to the crane span restrictions, and placing its long

dimension parallel to Mack Ave would have limited truck maneuverability. Allowing space on

each side of the lot allows for temporary truck parking as well.

Next the owner’s requirements were used in determining the approximate dimensions

and layout of the facilities. For rectangular structures, square structures have the highest area

to perimeter ratio, which translates into more efficient and economical buildings (less siding

required). Thus for an initial estimate, the square root of the area required was used as a

starting point. Then these dimensions were adjusted to fit the lot and module. The module

chosen was 8 feet. This module gives standard spans of 16’, 24’, 32’, 40’, etc. The

manufacturing area is 240’x224’ with column spacing of 40’ in the 240’ direction and column

spacing of 32’ in the 224’ direction. The short dimension is aligned on the middle of the

southwest side of the lot. Beams will span the long direction for economy purposes, and be

spaced 8’ apart (3 beams in between every column). This span can be used to support the HVAC

9

units on the roof, which are supported on its 20’ edges, which are 8’ apart. The girders are

spaced every 40’, perpendicular to the beams and placed above the columns.

The material handling area is adjacent to the manufacturing area, with dimensions of

80’x224’. The column spacing matches that of the manufacturing area, with 40’ spans

continuing from the manufacturing area to the material handling area, and 32’ spans running

along the 224’ side which is parallel and adjacent to the manufacturing area’s 224’ length.

However, the material handling area has no internal columns because they would restrict crane

movement. The beam and girder alignment is opposite of the manufacturing area because

without interior columns, there would only be one girder running the entire length of the area

without being supported. Instead the beams are spaced every 10’ and span the long direction.

The girders will span 80’ and be spaced every 32’, above the columns. Aligning the

manufacturing and material handling areas creates a wide open space for materials to travel

freely and it increases constructability.

The office is placed at the south corner of the manufacturing area. Its dimensions were

determined the same way as the material handling area – approximate a square while fitting

the module. The dimensions chosen were 80’x96’ for the 2 story area. The 32’ column span

continues down vertically from the manufacturing area and the 40’ span continues horizontally

across. The beam and girder system matches that of the manufacturing area because the

column spacing is the same. The location for the office keeps it from limiting truck

maneuverability. It is also closer to the parking deck employees will use.

The grid system for column spacing is constant and continuous for the entire facility.

This design might be modified if future design requirements call for it. For example, the detailed

10

load analysis might determine shorter spans are need. Expansion joints will also need to be

placed in the facility. Early estimations of the height of the manufacturing and material handling

areas yield conservative values of 36’ for each. This height allows tolerance for the roof pitch to

slope down from the max height of 36’. Having these areas are the same height, it will increase

constructability, as it will allow for metal decking and other materials to be continuous between

the two areas. Beam, girder, and truss estimations made in the load section were used in the

determination of ceiling height, and the original estimations based on span to depth ratio was

discarded. The office height is estimated to be 26’.

11

Main Wind Force Resisting System and Components and Cladding

The main wind force resisting system and the components and cladding were designed using the

wind load determined in the load section and the analysis steps provided in chapters 26, 27, and 30 of

ASCE/SEI 7-10. The manufacturing and material handling areas were analyzed as one building for the

main wind force resisting system, and the office had its own analysis. Some cases yielded the same

results for each building respectively, so repeat calculations were not done, but rather the symmetry of

the case was noted and the previously calculated value taken. Once the wind pressures were

determined, the four design load cases were examined. Then the MWFRS was designed based on the

controlling values from the wind load cases. The MWFRS was analyzed as a truss for the roof sections

and vertical wall sections. Then member selection for tension rods was done with AISC Steel

Construction Manual. The components and cladding design was done with the same process –

determine loads for all sections, and then design the wind girt members.

12

Summary

The components and cladding was used to find pressures and forces on the wind columns, the

wind girts, and roof beams. The wind girts are A36 material with Fy = 36ksi and are spaced 9’ apart and

the sag rods are placed every 8’. The wind girts were designed according to ASCE 7 and all wind girts are

C8x11.5.

The MWFRS for the office does not include a horizontal roof truss or inter-story truss because

the composite floor and metal roof deck make the structure rigid, meaning the wind force is transferred

to the external walls and columns through the beams and girders of the roof and 1 st floor. The load cases

included the wind forces on the wall that is adjacent to the manufacturing area even though it is mostly

blocked off due to manufacturing area. This simplified the analysis and yielded conservative values for

wind loads. The max forces in the truss system were initially determined using SAP2000, but revised and

done with hand calculations (attached). Wind load cases 3 and 4 were not calculated because it was

determined that they do not control by inspection – each direction’s truss acts independently so the

reduced and combined loads in these cases are less than in cases 1 and 2. For case 2, the moments were

distributed by creating a couple that was applied at the outer edge of the building. These moments and

couples were also applied independently for each floor.

The MWFRS for the manufacturing and shipping area includes roof trusses running in each

primary direction with vertical cross bracing on the walls to distribute the forces to the ground. The

building was determined to be partially enclosed as defined by ASCE 7-10. A reduction factor for internal

air pressure coefficient was applied for buildings with large un-partitioned volume, which the shipping

and manufacturing area meet. The wind pressures were then calculated for each direction. The internal

pressure canceled for all wall loads but not for the roof. As with the analysis of the office, the effects of

the adjacent external walls (between the manufacturing and office area) were neglected to be

conservative and to keep the analysis simple. Next the load combinations were calculated by hand,

13

assessed with simple truss analysis, and the controlling values for axial tension forces were used to

design truss rods. For this analysis, some assumptions needed to be made. The exterior columns were

modeled as beams, and the wind load was distributed to the reactions at the roof and foundation. The

roof loads moved through beams and columns until it reached the MWFRS truss where the loads were

applied accordingly. The load cases with a moment were assessed by turning the moment into a couple

that acted on the outer edge of the building. Additional bracing was required along the edge of the roof

in the north and south direction of the manufacturing area because the wind columns had no roof

members to transfer load to. This bracing is also required on the outer edge of the shipping area for the

same reason. The reaction force was then transferred to the vertical truss that spans from roof to

foundation. Forces from wind case 1 controlled the design of members. Case 3 was not considered

because it was determined not to control by inspection. The trusses in each direction act independently,

and at the intersection between them the combined forces were not greater than in cases 1 and 2

because in one case they were zero force members. Once all the axial forces were determined the

members were selected. All members are tension rods, and their size was designed based on their axial

forces.

14

Composite Office Area Floor Framing Design

The composite office floor area plan was designed using LRFD load combinations. The loads

applied were either presented in the project write up, or were researched and are shown on the loads

spreadsheet. The floor consists of 10 different beams that needed to be designed. Design calculations

were determined for moment capacity, moment capacity under construction load, deflection under

construction load, live load deflection, the number of shear studs. Shear was not analyzed for the

composite floor because our beams/girders are 40 feet and 32 feet, respectively, and shear will not be a

controlling factor in this case. Shear and moment diagrams were constructed and are presented after

the design pages.

15

Summary

There were 10 different composite beams designed for the office floor. All beams used for the

composite floor are A992 material with normal weight concrete at a compressive strength, f’c, of 3.5ksi.

The deck thickness is 3” with a concrete slab thickness of 2”. All beams are simply supported and the

location of max moment varied depending on the loading pattern. Max shear was located at the

supports, but was not analyzed due to shear not being a controlling factor in beams. The beams were

controlled by deflection limits, L/360 for interior, and L/600 for exterior, moment capacity, and

cambering limits. The girders were generally controlled by moment capacity, Mu = 1.2D +1.6L.

To determine the required beam, the required moment was calculated using statics along with

shear and moment diagrams. Once Mu was determined, the effective width was found along with

Ccmax, the maximum compressive strength of the concrete slab. Next a beam size was estimated and

Ts was calculated. From there, the PNA was determined and depending on whether its location was in

the concrete slab or the steel beam the appropriate method was used to determine to overall moment

capacity of the composite section. If the beam was sufficient, required moment and deflection under

construction load were determined. From the deflection under construction load, cambering was

determined and ranges from 0.00”-1.75”. For this equation, the un-factored dead load was used. Then

the deflection due to live load was calculated and was compared to L/360 or L/600. For this equation,

the un-factored live load was used. If the original beam selected failed any of these conditions, a new

beam was selected and the same process was repeated. If the beam met all requirements, the number

and spacing of the shear studs was calculated. The shear studs used were 3/8” and the strength per stud

was found in Table 3-21.

Depending on the loading pattern of the beam, Mu and max deflection were determined from

Table 3-23, primarily cases 1, 5, and 6. Case 6 does not give a deflection equation, so the double

integration method was used, and the x-value used corresponded with the point of max moment.

16

Beams 12, 13, and 16 were not analyzed as composite sections because for some length, there

was no metal deck and concrete slab atop the beam. These beams bordered the elevator, stairs, or

were an edge beam. The differences in the analysis of these beams were that the moment capacity of

the beam was determined from AISC Chapter 16 Section F, and the Moment of Inertia for live load

deflection was that of the beam and not of the composite section. Depending on the unbraced length of

the beam, EQN F2-1, F2-2, or F2-3 was used.

17

Snow Loading and Roof Framing Design

Snow Load

For the determination of the roof snow loads including the snow drifting loads, ASCE 7-10

chapter 7 devoted entirely to snow loads was used. The ground snow load used to begin the drift

calculations was 30 psf. For this project, snow drift calculations needed to be done for 4 different items

on the roof, and are as follows: 1) the roof step between the office and the manufacturing, 2) the HVAC

unit on the office roof, 3) the HVAC units on top of the manufacturing center, and 4) the roof parapets

on the office roof. There was not a snow drift calculation performed for a parapet on the manufacturing

center because the manufacturing center was designed to not have a roof parapet. Before the snow

drift loadings could actually be calculated, certain assumptions and classifications had to be made. The

first classification criteria needed is whether or not the roof being analyzed is a flat roof or a pitched

roof. The next set of classifications to be considered is an exposure classification, a risk classification,

and an assumption as to whether or not the items are heated or unheated. Once these considerations

are determined, the snow drift calculations can be determined for both leeward and windward snow

drifts. Further explanation of this process is given in the snow load summary section.

Roof Framing Design

For the roof design, the base snow load used was 30psf along with the snow drift calculated

previously around the HVAC units, parapets, and the drift between buildings. The wind loads used were

calculated previously under the components and cladding section and the MWFRS. The MWRFS wind

pressures were used on the girders when the tributary area was greater than 700ft. This is a slight over

design because the snow drift will move some of the base snow load to different areas. The allowable

roof deflection due to transient loads, snow load, was L/240 for interior beams and L/600 for exterior

18

beams. For the deflection due to snow load, the load was increased by 15% to account for areas of drift.

The wall loads, manufacturing and office, will all be carried by the exterior roof beams. The majority of

the beams were designed in the hand calculations following this, and the girders were designed in the

spread sheet using the same process. The truss was designed with the point loads from all the beams

running above vertical truss members.

19

Summary

Snow Load

There are a total of 4 different items that were analyzed for snow drifting loads. The first item to

be analyzed was the HVAC units on the manufacturing roof. Both the roof and the HVAC unit were

considered to be fully exposed (Ce=0.9), heated components (Ct=1.0), and both had an importance

factor (Is) of 1.0 which corresponds to a risk category II building. With these values, the flat roof snow

could be determined and checked against the ASCE minimum value. For these HVAC units, the

calculated flat snow roof load was less than the ASCE minimum, therefore the minimum was used. The

next step was to calculate the leeward and windward drifts for the long side of the HVAC’s twice

because for the windward drift the lu values are different. The short sides of the HVAC’s were not

considered for snow drifting because their length (8’) is less than 20’; therefore according to ASCE snow

drifting does not need to be considered. For both sides of the HVAC units, the windward drift condition

controlled. With the controlling condition, the heights of the drifts were calculated and the

corresponding drift pressures for that drift height. Only one HVAC was analyzed on the manufacturing

roof because the placement of them dictates that all the snow drift calculations would be identical to

the one calculation that was performed.

The second item analyzed was the roof step between the office roof and the manufacturing

roof. All of the assumptions and classifications were the same as before, except for the exposure

category of the office roof, which was considered to be partially enclosed (Ce=1.0). As was before, once

the flat roof snow loads were calculated the roof step was analyzed for both leeward and windward

snow drift. For the roof step, the leeward drift condition controlled and the height of the drift for the

leeward condition was used to determine the snow drift loading for the roof step between the office

roof and manufacturing roof.

20

The third item to be analyzed was the roof parapet on the office roof. For this case, all of the

assumptions and classifications remained the same as before other than the parapet was assumed to be

an unheated element (Ct=1.2). The office roof was considered to have 3 parapets, but only 2 of them

were considered because the third has the same lu value as one of the others, therefore its drifting

loads will be the same. As like the manufacturing HVAC’s, after considering both leeward and windward

drift for the different sides, it was found that the windward condition controlled for both cases. The

heights of these drifts found in the windward conditions were used to determine the drift loadings on

the office roof parapets.

The final item that was analyzed was the HVAC unit on the office roof. The assumptions and

classifications remained the same as the HVAC units on the manufacturing roof other than the exposure

classification of the office roof (Ce=1.0). Again, the flat roof snow loads were determined and then the

HVAC unit was evaluated on both of its long sides because again the lu values were different for each

side. Once again, after determination of leeward and windward drifts it was found that the windward

condition controlled for both of the long sides. The heights of the drifts found under these conditions

were then used to determine the drift loadings on the office HVAC unit.

Roof Framing Design

There are a total of 33 different beams on the roof of the manufacturing and office. The beams

were analyzed using LRFD Load Combinations. Load Combination 2 controlled for the roof (1.2D +1.6S

+.5W). Roof beams were checked against moment capacity, deflection due to snow load, and

cambering limits. The span of the roof beams was 40’ and the girder span was 32’ but because of the

metal decking, the unbraced length of these beams is 0’. This causes the plastic moment to be the

failure mode and EQN (F2-1) was used. The manufacturing areas primarily consisted of the same beams

because the loading pattern was consistent. Some beams were different due to the HVAC unit, the span

of the beam, and the tributary area of the beam such as the beams atop the shipping area. The roof

21

beams that were a part of the MWFRS were designed as beam columns and contained axial load and

moment. Multiple load combinations were checked in this case because the axial load due to wind was

large in some areas.

The office roof was a little more complex due to snow drift loading and the location of the HVAC

unit. Some beams carried the weight of the HVAC, snow drift from the HVAC, and snow drift from the

parapets, while others carried the basic loads, dead, snow, and wind. Most beams were governed by

moment capacity while some were governed by snow deflection and cambering depending on the

location of the beam. The exterior girders are fairly large compared to the rest of the beams because

they carry the full wall load of 50psf (26ft height). For the exterior beams adjacent to the manufacturing

building, the wall load was accounted to be 20psf because there are no brick siding which is roughly

30psf.

The truss had its bays in line with the overhead beams, so vertical members were directly under

the beams. The truss was set at 5’-0” depth and analyzes with this as the center to center spacing. Once

members had been selected, the outside to outside spacing was calculated. The truss was analyzed in

SAP2000. Then a quick hand calculation check was done to ensure the values from SAP2000 were

accurate. The top and bottom chords of the truss were designed based on the controlling axial loads,

which for both were in the bays at midspan. Then the tension members (diagonals) and compression

members (verticals) were designed based on AISC design tables. An excel spreadsheet was made to

calculate the required cross sectional area for the tension members. The dead load camber was

calculated using the method of virtual work. A unit load was placed at midspan where the deflection will

be greatest, and member forces were found in SAP. Then the values were input into another excel

spreadsheet and the camber was determined. The same method was used to check transient load

deflection. LRFD load combination 6 was used to check for net uplift and no uplift was present. Once this

22

was complete the sway frame was designed based on 3% of the maximum bottom chord force

multiplied times the number of trusses. It was designed for both compression and tension.

23

Column Design

The column design was completed after all the beams and girders had been designed. The loads

were determined by comparing the reactions from these beams and girders against the load from

tributary area and they all matched. Columns were designed with the AISC steel construction manual,

part 4 (columns) and 16 (specifications). Interior columns were mostly the same as loading only varied

slightly due to the HVAC units. The exterior columns were beam columns and varied based on wind

pressure from components and cladding. The members were selected from AISC table 4-1 and the one

that was lightest (most economical) was then analyzed to ensure it passed.

24

Summary

The column design procedure was as follows; determine how many different columns were

needed and where, then check the loading based on tributary area and the reactions from the beams

and girders. Once these loading patterns were determined to be in agreement the factored load

combinations (3 and 4) were calculated. Then the columns were designed with the AISC steel manual.

Certain assumptions had to be made during the analysis and design. The first was that all

connections were pinned so all K values for the effective length = 1.0. This assumption is accepted for

the base of columns, and for the top there are no moment connections to the beams and girders, so this

was reasonable. Both areas were considered rigid with no sway, so for all columns no second order

analysis was necessary. For the interior columns, all compressive axial loads were determined to be

concentric. The justification for this is that the beams and girders that frame into the column provide it

with adequate stiffness to prevent any eccentric loading from making a noticeable difference. The

elements that framed into the web are concentric and the ones that frame into the flange usually offset

each other or very nearly did. This assumption allowed for all interior columns to be modeled simply as

compression members and not beam-columns. Another assumption was that for the office, the 1 st floor

section of the column controlled its design. The justification for this is that the loading was greater

because it included the floor load and the roof load and the unbraced length was greater by 1 foot

because the column extends 1 foot into the ground. A larger load and greater unbraced length for the

same column will always control. The exterior columns and wind columns also operated under the

concentric axial loading assumption. The exterior columns were all beam columns because of the wind

force from the wind girts. They were designed with the greater load calculated with the Pu equivalent

chart. Once a member was selected and passed, the other load combination was checked as well.

25

Foundation Analysis Design

Because the structure is within close proximity to Lake St. Clair, the soil underneath the

structure has a low bearing capacity and piles are used for the foundation design. The piles used are 15

ton, 6” diameter steel pipe piles and are 40’ in length. Pile caps were placed underneath each column

and the caps vary in size depending on loading pattern. The foundation line is 1’-2” underneath the

established ground level and the caps are 28” deep to reach the bottom of frost depth along the

perimeter of the building. The grade beams around the office are 16” wide by 28” deep but vary in

length. The grade beams underneath the manufacturing warehouse are 8” wide by 28” deep and also

vary in length. Each grade beam is supported by 1 pile centered underneath the beam. The grade

beams were modeled to carry only wall loads.

26

Summary

To design the pile caps, ASD and LRFD load combinations were used depending on the type of

analysis. ASD Load combinations 2, 4, 6a were analyzed while LRFD load combinations 2 and 3 were

analyzed. The pile caps carry the loads from the columns and for the manufacturing area only

incorporated the roof, and the wall loads, while in the office the column supports the roof load, wall

loads, and the second floor loads. Because of the second floor, a different load combination controlled.

To start off the design, ASD loads were used to determine the number the number of piles needed and

to determine the size of the pile cap. Once this was determined, the piles were arranged accordingly to

meet design specifications of the CRSI Handbook. The minimum edge distance, minimum embedment

length, and minimum spacing between piles were all met. Once the arrangement of the piles was

determined, LRFD loads were used to analyze the beam for one way shear, in both directions, punching

shear of the column and piles individually, deep beam shear, and flexural reinforcement. The interior

caps were generally governed by minimum design specifications along with pile bearing limits, while the

exterior caps were governed by frost depth and pile bearing limits. Depending on the size of the cap

and the arrangement of piles, punching shear was not an issue and the cap would only fail in one way

shear. The design of the flexural steel was generally controlled by the minimum area of steel required

and this greatly reduced the development length of the reinforcement which was sufficient for all caps.

All the square pile caps have identical rebar in each direction.

The grade beams were designed to carry the wall loads and were used to maintain a depth

sufficient enough to keep frost out. Positive and negative reinforcement was designed for the grade

beams because they were treated as continuous beams and have both positive and negative moments

at different areas of the beams. A pile was placed underneath each grade beam at mid-span to help

support the beam and to relief some weight off of the pile caps. The grade beams shear strength due to

the concrete was sufficient enough to not require stirrups but stirrups were placed in the grade beam at

27

all lap splices. All bars are to be spliced while in compression so ACI 12.16.1 is permitted to be used.

The top bars are to be spliced at mid span between the edge of the pile cap and the pile supporting the

grade beam, while the bottom bars are to be spliced above the pile supporting the grade beam.

28

Crane Girder and WF Combination Girder Analysis and Design

The initial specifications for the crane were given in the problem statement and research was

done to find a crane that met those specifications. The specifications given were that the crane had to

have a 40 ton capacity, a minimum bridge span of 75’, a maximum span of 100’ and a minimum 20’ hook

height. With these in mind, a crane from Munck Cranes, Inc. will be used. The dimensions and design

specifications for this crane are shown previously under the loads section. The crane runs the entire

length of the building and has a span of 80’. The girders were designed as simple supports and

therefore only positive moment was considered. The columns underneath the crane girder were

analyzed as step columns but were not designed for this project.

Summary

To start off the design of the girder, a minimum moment of inertia was found due to deflection.

After a moment of inertia was calculated, a section was selected from Table 1-19 from AISC. The section

chosen was a W33x118 with a C15x33.9 channel on top. After the section was chosen, the maximum

shear and moment were calculated using LRFD load combinations. The maximum shear and moment

were dependent on the position of the crane, so different orientations of the crane caused different

load values. Once these calculations were determined, the capacity of the section was found. To do

this, first the girder was analyzed to see if it would fail in plastic moment, inelastic torsional buckling or

elastic lateral torsional buckling. For our section being 32’ in length, it was found to fail in ITB. Lr was

determined to be 40.2’ and Lp was 10.9’. Knowing these values Mn was calculated in the X and Y

directions. These numbers were sufficient for the loading and finally bi-axial bending was checked and

passed.

29

Additional Design Beyond Minimum Requirements – Base Plate Design

The additional design picked for the project was the design of the base plates and anchor rods

for all columns. A spreadsheet was developed to determine the required thickness based on the inputs

of loading, column size, foundation size, etc. A conservative clearance of ± 4” was given on each side of

the column. Each different column (C1, C2, C3, etc.) had a base plate designed for it. Additionally,

columns included in the MWFRS truss had additional axial load and some shear force at the base plate.

In some cases this additional load increased the thickness of the base plate. The anchor rods did not

need to be designed for tension because there was no uplift or moment in the base plate. For this

reason all anchor rods were the same, with a diameter of ¾” and length of 12”. These anchor rods were

adequate when checked for shear force.

Summary

The design of most of the base plates was relatively simple because they were modeled as

having axial loading and no moment force (consistent with the pin connection assumption in column

design). This assumption works because the wind force that would’ve caused a moment is instead

distributed to the base plates below the columns included in the MWFRS vertical truss. These base

plates had greater axial load because of the MWFRS truss in addition to shear force from the diagonal

members that frame in at the base. Since the design of connections that frame into base plates was

never covered, the effect this may have had on the base plate design was not considered.

30

Final Engineering Plans, Sections, Elevations and Details

Summary

31

Overall Summary and Conclusions

The final design of the facility came together after making some important assumptions and

decisions. The decisions made during the initial conceptual design had far reaching effects. Overall, the

goal of the design was to be economical and efficient. The layout of the lot was designed to maximize

maneuverability for the trucks. Some of these assumptions were made in order to simplify calculations

and keep the amount of work and calculations needed to a manageable level. One such decision was

modeling all connections as pin connections. This is a conservative measure, but it eliminated the need

to; calculate the stiffness at connections, use the alignment charts, design base plates with moment.

Since the beams framed into the columns and were pin connections, it made them simply spans rather

than continuous beams. Another assumption was that the friction between the ground and the building

was sufficient to resist any lateral force caused by the wind. This eliminated the need for piles to be

designed for shear force and have some battered. Setting the height of the manufacturing and material

handling area the same (36’-0”) simplified calculations as well because it eliminated the need for

additional columns of different lengths and eliminated snow drift and wind loads caused by a step in the

roof. Despite these design decisions, there were still a lot of different beams/girders that needed to be

designed (almost 50 altogether). A few beams were repeated a lot and the rest were designed for

special cases, like the beams around the elevator, HVAC unit, beams in the MWFRS truss, etc. Another

assumption was that any eccentricity in the pile caps due to grade beams was insignificant enough to be

ignored because those same grade beams resist rotation in the pile cap.

There were many lessons learned working on this project but 3 stuck out the most. The first is

that each decision made can have far reaching effects and they need to be monitored. An example of

this was the adding a parapet to the office roof. This decision was made early, but no one specified the

32

height of the parapet until after the wind analysis had been done. Once the height was set the wind

loads increased and the office’s lateral force resisting system had to be redesigned for this greater load.

Had the parapet been specified before the wind analysis was done, a considerable amount of time could

have been saved. The next lesson learned was to double check all the work/calculations done. The

consequences of not doing this are similar to the consequences of the last example – it could result in a

domino effect of calculations needing to be redone. It could also result in the specification of inadequate

or grossly over designed members. No two minds think alike so another group member may see

something no one else does, especially when only one individual has put work in on that part of the

design. The third lesson learned was overall time management and organization. The amount of work

required was underestimated initially and this resulted in more stress as the deadline for submissions

approached. It also resulted in less precise work because of time constraints. The amount of calculations

and spreadsheets was also underestimated initially and this resulted in things getting lost. Eventually all

of the calculations were organized and placed in a binder that all group members could use.

If a project like this is done again several changes to the approach of the design would be made.

More work would have gone into investigating the most economical layout/design for the column

spacing, beam spacing, truss depth, and other aspects. The column spacing used here could have been

greater. Another change would be to develop and use more spreadsheets to avoid wasting time on

repetitive hand calculations, or worse, redoing calculations. The big change would be the order in which

things were done. The design of all parts depend on certain parameters and also affect other parts that

need to be designed. So anything that could affect the loading on a beam would be designed and

specified before the design of the beam began. Also the process of the design itself would be checked

with the person in charge more frequently so less time is wasted doing improper design calculations.

This arose when the pile caps had been designed before the grade beams were considered. This

required redesigning the pile caps to factor in the weight of the grade beams. It was a recurring problem

33

that the proper procedure was not known initially, so after a submittal was graded, a section had to be

redone entirely with the proper procedure.

34