SEISMIC EVALUATION OF RC FRAMED STRUCTURE WITH AND … · SEISMIC EVALUATION OF RC FRAMED STRUCTURE WITH AND WITHOUT OPENING IN MASONRY INFILLS SANGEETHA I NAIK 1, ASHWINI G 2. 1Mtech

DOI : 10.23883/IJRTER.2017.3417.YBYGJ 299

SEISMIC EVALUATION OF RC FRAMED STRUCTURE WITH

AND WITHOUT OPENING IN MASONRY INFILLS

SANGEETHA I NAIK 1,

ASHWINI G 2.

1Mtech Student, Dept of Civil Engineering, East West Institute of Technology, Bangalore,

2Associate Professor, Dept of Civil Engineering, East West Institute of Technology, Bangalore,

Abstract— The current pattern of building development in urban and semi-urban zones, similar to a

few different nations around the globe, is strengthened solid edges. The vertical space made by

strengthened cement (RC) shafts and segments are typically filled in by dividers alluded to as brick

work infill divider or boards. The dividers are ordinarily of consumed dirt blocks in concrete mortar.

One of the principle reasons in utilizing brick work infill is economy and simplicity of development,

since it utilizes locally accessible material and work expertise. Additionally, it has decent solid and

warmth protection and waterproofing properties, bringing about more noteworthy solace for the

occupants. The infill dividers are here and there modified to suit the changing practical needs of

tenants. The progressions are done without considering their unfavorable impacts on the general

auxiliary conduct. The regular limited component displaying of RC structures without considering

the impact of infill in the logical model renders the structures more adaptable than they really are.

Therefore a construction standard forces a furthest point of confinement to the common time of a

structure by method for exact relations. Since infills are not considered in ordinary displaying in

seismic plan, their commitments to the sidelong firmness and quality may nullify the examination

and proportioning of auxiliary individuals for seismic resistance on the premise of its outcomes.

I. INTRODUCTION

1.1 General Conduct of brickwork infill is hard to foresee as a result of noteworthy varieties in material

properties and disappointment modes that are weak in nature. If not prudently set, amid seismic

excitation, the infills likewise have some antagonistic impacts. One of the real sick impacts is the

delicate storey impact. This is because of nonappearance of infill divider in a specific storey. The

nonappearance of infill in some bit of a building arrangement will actuate torsional minute.

Likewise, the mostly infilled divider, if not appropriately put may instigate short segment impact

subsequently making limited anxiety fixation.

This is primarily because of absence of by and large acknowledged seismic outline strategy in the

National Building Codes that fuses auxiliary impacts of infill. Indeed not very many codes on the

planet as of now give determinations to the same. Consequently, there is a reasonable need to build

up a vigorous outline procedure for seismic plan of brickwork infill strengthened solid structures.

The open ground storey confined building acts distinctively when contrasted with an exposed

encircled building or a completely infilled surround working under parallel load. An exposed edge is

a great deal less stiffer than a completely infilled outline; it opposes the connected sidelong load

through casing activity and shows very much dispersed plastic pivots at disappointment.

At the point when this edge is completely infilled, truss activity is presented accordingly changing

the horizontal load exchange instrument. A completely infilled outline indicates lesser between

storey float, in spite of the fact that it pulls in higher base shear (because of expanded solidness).

Incorporation of firmness and quality of infill dividers in the open ground storey building outlines

International Journal of Recent Trends in Engineering & Research (IJRTER)

Volume 03, Issue 08; August - 2017 [ISSN: 2455-1457]

@IJRTER-2017, All Rights Reserved 300

diminishes the essential day and age contrasted with an uncovered casing and therefore expands the

base shear request and the plan compels in the ground storey shafts and segments. This expanded

plan drives in the ground storey pillars and sections of the open ground storey structures are not

caught in the customary uncovered edge investigation.

A fitting approach to break down the open ground storey structures is to demonstrate the quality and

solidness of infill dividers. Sadly, no rules are given in IS 1893: 2002 (Part-1) for demonstrating the

infill dividers. As an option an exposed casing investigation is for the most part utilized that

disregards the quality and firmness of the infill dividers. Stone work infill dividers are generally

utilized as allotments everywhere throughout the world. Confirmations are that ceaseless infill brick

work dividers can diminish the weakness of the fortified solid structure. Regularly stone work

dividers are not considered in the plan procedure since they should go about as non-basic individuals

or components. Independently the infill dividers are firm and weak however the edge is moderately

adaptable and flexible. The composite activity of shaft segment and infill dividers gives extra quality

and solidness. Diverse sorts of explanatory models in light of the physical comprehension of the

general conduct of an infill boards were created throughout the years to recreate the conduct of

infilled casings.

1.2 Masonry Infill Wall Workmanship infill alludes to brick work used to fill the opening in a basic casing, known as the

jumping outline. The bouncing edges of steel or fortified cement is included the sections and upper

and lower pillars or pieces that encompass the stone work infill and give auxiliary support. At the

point when legitimately outlined, brick work infills give an extra solid, pliable framework for

opposing sidelong loads, in-plane and out-of-plane.

Solid workmanship infills can be composed and nitty gritty to be a piece of the horizontal drive

opposing framework (taking an interest infills) or they can be planned and point by point to be

basically segregated from the parallel compel opposing framework and oppose just out-of-plane

burdens (non-taking an interest infills). Taking an interest infills shape a composite auxiliary

framework with the jumping outline, expanding the quality and firmness of the divider framework

and its imperviousness to tremor and wind loads. Non-taking an interest infills are point by point

with basic holes between the infill and the bouncing edge to keep the unintended move of in-plane

burdens from the casing into the infill. Such crevices are later fixed for other code necessities, for

example, climate insurance, air invasion, vitality protections, and so forth.

1.3 Interaction between building and masonry infill walls Global behaviour

At the point when there is a border contact between the brick work infill dividers and the edge, in

common circumstances of follower strong infill dividers, the impact of firmness increment (and

furthermore dispersal) impacts the building reaction. On account of infill dividers manufactured

detached from the structure (not in adherence with the casing components), it is likely that infill

dividers go about as an extra mass connected to the structure just, and ought not have other critical

impacts.

• Increased sidelong inflexibility of the structure; on account of adaptable structures from

seismic zones with little estimations of the period Tc, the seismic powers increment over the

ordinary level.

• Creating some vertical abnormalities by expanding the malleability request at one storey, or

making some even anomalies by expanding the outfit torsion subsequently of altering the focal

point of unbending nature; for the outline of structures in seismic zones, these circumstances

must be constantly kept away from.




• Creating a few requesting of short components sort, having a danger of break to shear

constrain, because of the way that on the deformable zone of the section the shear compel is

significantly bigger than in the ordinary case (likewise regarded as nearby impact).

1.4 Objectives of the study The RC outline structures with infills are dissected with Etabs programming and the parameters, for

example, essential day and age, rooftop removal, basic part compels, bowing minutes, base shear are

ascertained. At long last anticipating the conduct of the infill RC outline structures amid seismic

activity it is contrasted and the exposed casing structures.

• To concentrate the viability of infill divider in the RC confined building.

• To concentrate the conduct of edges for various building pieces like Concrete squares and AAC

pieces.

• To concentrate the conduct of edges with the diverse rate of opening in the infills.

• To concentrate the genuine conduct of the current working under the impact of seismic tremor

strengths. The infills are demonstrated utilizing an ASCE code as an equal corner to corner

strut part.

• Comparing the variety of base shear, storey float, storey relocations, top speeding up, pinnacle

uprooting for RC structures with and without opening in infills and furthermore for various

stone work pieces.

• Conclusions are made in light of the impact of infills on general execution of RC casing laying

on various rate of openings and brick work pieces.

1.5 Concept of equivalent diagonal strut Specialists have proposed different approximations for the width of equal corner to corner strut.

Initially proposed by polyakov and in this manner created by numerous examiners, the width of strut

relies on upon the length of contact amongst divider and section αh and between the divider and bar

αL Holmes prescribed a width of the corner to corner strut equivalent to 33% of the length of the

board. Stafford smith built up the detailing for αh and αL on the premise of bar on a flexible

establishment. The accompanying conditions are,

Where

Em and Ef = elastic modulus of the masonry wall and frame material respectively

Ic and Ib = moment of inertia of column and beam frame respectively.

t,l = Thickness and length of the infill wall, respectively

Hendry has proposed following equation to determine equivalent strut or equivalent or effective

width of strut.




Fig 1.5 Equivalent diagonal strut

1.6 Calculation Of Compressive Strength Of Masonry Expected compressive strength of masonry is calculated as per IS 1905.

Height of the wall “H” = 2.9m

Thickness of the wall “t” = 0.2m

Size of concrete block = 0.4 x 0.2 x 0.2 m

Compressive strength of concrete block = 7.5 N/mm2

Type of mortar: M2 (1:6) = 3 N/mm2

As per IS 1905 clause 5.4.1 table 8, basic compressive stress of masonry

for the above data fb = 0.59 N/mm2

Stress reduction factor:

Eccentricity = 0

Slenderness ratio = Effective height = 0.75H

Effective thickness t

Slenderness ratio = 0.75*2.9 = 10.88

0.2

As per IS 1905 clause 5.4.1.1 table 9, stress reduction factor of masonry

for the above slenderness ratio and eccentricity ks = 0.868

As per IS 1905 clause 5.4.1.2, Area reduction factor ka = 1

As per IS 1905 clause 5.4.1.3 table 10, Shape modification factor kp = 1.1

Compressive strength of masonry = fb * ks * ka * kp

= 0.59*0.868*1*1.1

= 0.56 N/mm2

1.7 Calculation Of Expected Modulus Of Elasticity Of Masonry As per FEMA 356 clause C7.3.2.4 the expected modulus of elasticity of masonry

Eme = 550*fme

Eme = 550*0.56 = 308 N/mm2

Calculation Of Strut Width “A” In the present study, for both the L and C shape structures, the height of the infill

wall remains same, as only one beam type is used in the structure. But three different

lengths of infill wall are obtained and hence three strut elements have to be defined, for

which the width has to be calculated. From the equations 4.1 and 4.2 the width of the

equivalent diagonal struts are calculated.

The following data remains same for the three strut models.

hcol = 3000mm = 118.1 inches

hinf = 2550mm = 100.39 inches.

Efe = 20000 N/mm2 = 2900.73 ksi

Eme = 308 N/mm2 = 44.67 ksi

Icol = 1750*106 mm4 = 2162.24 in4

tinf = 200mm = 7.87 inches




1) Infill panel of length 5.0m:

Ѳ = 0.3 rad

λ = 0.05751

a = 474 mm

2) Infill panel of length 2.5 m:

Ѳ = 0.5 rad

λ = 0.05855

a = 315 mm

3) Infill panel of length 3.15 m:

Ѳ = 0.4 rad

λ = 0.05626

a = 369 mm

II. METHODOLOGY

1. Models used for analysis

In this chapter, the general procedure of modeling the different types of structure is included in the

simple procedure. The Basic model is created first and then the other configurations are then updated

to models the different types. Here we are presenting 5 different models.

1. TYPE A – Bare frame without infill wall effect.

2. TYPE B – Bare frame with solid infill wall effect.

3. TYPE C – Bare frame with AAC infill wall effect.

4. TYPE D – Bare frame with solid infill wall effect with 20% opening.

5. TYPE E – Bare frame with AAC infill wall effect with 20% opening

There are two commonly used procedures for specifying seismic design lateral forces:

1. Equivalent Static Force Analysis

2. Dynamic Analysis

2.1 Equivalent Static Force Analysis The equivalent lateral force for an earthquake is a novel idea utilized as a part of earthquake

engineering. The idea is attractive because it changes a dynamic analysis into partly dynamic and

partly static analysis for finding the extreme displacement (or stresses) induced in the structure due

to earthquake excitation. For seismic resistant design of structures, only these maximum stresses are

of interest, not the time history of stresses. The equivalent lateral force for an earthquake is

characterized as arrangement of lateral static forces which will produce the same peak response of

the structure as that acquired by the dynamic analysis of the structure under the same earthquake.

2.2 Dynamic Analysis Response-spectrum analysis gives knowledge into dynamic behaviour by measuring pseudo-spectral

acceleration, velocity, or displacement as a function of structural time period for a given time history

and level of damping. It is practical to envelope response spectra such that a smooth curve shows the

peak response for each realization of structural period and shall be performed using the design

spectrum specified in Clause 6.4.2 or by a site specific design, spectrum mentioned in Clause 6.4.6

of IS 1893 (2002).




III. STRUCTURAL PARAMETERS

Structure Ductile Shear

wall

with SMRF

No. of storey G + 5

Storey height First

storey

3.0 m

Upper

storey

3.0 m

Type of building use General

Foundation type Isolated footing

Seismic zone V

Material Properties

Young’s Modulus of M35

Concrete, E

25.00x106 KN/m

2

Grade of Concrete M35

Grade of Steel Fe 500

Density of reinforced concrete 25 KN/m2

Member Properties

Thickness of slab 0.15 m

Beam size 0.20 x 0.45 m

Column sizes Refer table-

Thickness of Shear walls 0.20m

Assumed Dead Load Intensities

Roof finishes 1.50 KN/m2

Floor finishes 1.50 KN/m2

Live Load Intensities

Roof 1.50 KN/m2

Floor 2.00 KN/m2

Earthquake LL on slab as per clause 7.3.1 and

7.3.2 of IS 1893 (part 1) -2002

Roof 0 KN/m2

Floor 0.25 x 3.0 = 0.75

KN/m2

3.1MODEL DESCRIPTION

Type - A

Fig 3.1.1 First Storey 3D of Type –A




Type-B

Fig 3.1.2First Storey 3D of Type –B

Type-C

Fig 3.1.3 First Storey 3D of Type –C

Type-D

Fig 3.1.4 First Storey 3D of Type –D

TYPE-E

Fig 3.1.5 First Storey 3D of Type –E




IV. RESULTS AND DISCUSSION.

4.1 Displacement comparison

FIG 4.1Comparison of storey v/s displacement for G+5 storey different models in X direction

The displacement of regular model is more in comparative to other models. The type B is

showing controlled displacement. As the strut is effectively working in this type. The effectiveness is

not much noticed in AAC block with opening.

4.2 Study Of Inter Storey Drift (Equivalent Static Analysis);

FIG 4.2 Comparison of storey v/s storey drifts for G+5 storey different models in X direction

The inter storey drift ratio is more in regular model as compared to few other models. In the TYPE B

showing better performance out of other models. The least effective is the AAC block model with

opening.

4.3 Time Period (Equivalent Static Analysis);




FIG 4.3Comparison of mode numbers v/s time period for G+15 storey different model

The regular model Type A is more ductile than other models. The TYPE C seems to exhibit highest

ductility compared to other structural systems as the type C possess more flexibility. TYPE B shows

brittle nature comparatively.

4.4 Study Of Base Shear (Equivalent Static Analysis): The table below shows different base shear values for G+5 storey different models

Table 4.5 Base Shear

G+5 STOREY

TYPE

A

TYPE

B

TYPE

C

TYPE

D

TYPE

E

1631.9

9

1250.9

9 1110.2 1250.99 1110.2

FIG 4.4 Comparison of base shear v/s models of G+ 5 storeys.

The base shear value directly depends on the weight of the building. The TYPE A is having higher

base shear values compared to other models. The TYPE E is having lowest base shear value

compared to other models.

4.5 Studies On Displacement (Response Spectrum Analysis):




Fig 4.5 Comparison of storey v/s displacement for G+5 storey different models in X direction

The response spectrum analysis will give the actual results compared to static analysis. The

displacement of regular model is more in comparative to other models. The type B is showing

controlled displacement. As the strut is effectively working in this type. The effectiveness is not

much noticed in AAC block with opening.

4.6 Study Of Drift (Response Spectrum Analysis);

FIG 4.6 Comparison of storey v/s storey drifts for G+5 storey different models in X direction

The inter storey drift ratio is more in regular model as compared to few other models. In the TYPE B

showing better performance out of other models. The least effective is the AAC block model with

opening.

V. CONCLUSIONS

• The results obtained from RS analysis will be much practical and gives the lower displacement

& deformations compared to linear static analysis.

• The values obtained from static analysis seems impractical as the ESA will gives the much

lateral resistant design, there by considering heavy structural design of structure. Which will

increase the self weight and also the construction cost.

• The Intern Storey drift values will increases as we move down stories and after few levels it

will vary inversely.

• The RSA shows better practical results compared to static analysis. The Type B model, the

Solid block masonry without opening will perform better in seismic conditions.

• The Time period and base shear value will not vary much for static and dynamic analysis,

since these values are always dependent on building features not on seismic behavior.




• The time period will depend on the flexibility of the building, more the time period more the

flexibility. The building model type A is exhibiting more brittle, where as the model type C is

exhibiting ductile behavior.

• The Base shear value is less in the AAC block model compared to Solid block model systems.

Since base shear depends on the load. The regular model posses more load, so the building

exhibits more value of base shear.

5.2 SCOPE FOR FUTURE STUDY: The project can be continued by further studies as stated below:

• The different block masonry can be tested to get the effective building systems.

• The soil structure interaction can be considered to find the actual spring stiffness behavior for

the time historey analysis.

• The Non linear push over analysis can be tried to get the actual behavior and the failure

locations prior to strengthen the weaken locations.

• The different heights of the buildings can be considered to check the effectiveness of the

different types of blocks and their behavior.

REFERENCES I. BhagavathulaLohitha 1 , S.V.Narsi Reddy2 Earthquake Resistant Design Of Low-Rise Open Ground Storey

Framed Building 1student,2asst.Professor, Department Of Civil Engineering, Malla Reddy Engineering College,

Secunderabad, Telangana State, India

II. S.Niruba, 2 K.V.Boobalakrishnan, 2 K.M.Gopalakrishnan Analysis Of Masonry Infill In A Multi-Storied

Building Assistant Professor, Civil Engineering Department, Erode Sengunthar Engineering College,2014.

III. Praveen Rathod, 2 S.S.Dyavanal1 Seismic Evaluation Of MultistoreyRc Building With Openings In

Unreinforced Masonry Infill Walls With User Defined Hinges Pg Student Civil EnggDeptBvbcet, Hubli.2

Professor Civil Engg. Dept. Bvbcet, Hubli. 2014

IV. Manoj Bhaskar1 S. S. Khuswah2 Ranjeet Joshi3 Seismic Evaluation Of Rcc Building With Softstorey At

Ground Floor 1,2,3department Of Civil Engineering 1,2,3uit (Rgpv), Bhopal (Mp) (2015)

V. MdIrfanullah1 ,MdIrshad Ali2 , Vishwanath. B .Patil3 Seismic Evaluation Of Rc Framed Buildings With

Influence Of Masonry Infill Panel 1, 2p.G. Student, 3professor, Structural Engineering Department, P.D.A.

College Of Engineering, Gulbarga-585102, Karnataka, India(2013)

VI. Nitesh Singh1 , V. K. Verma2 1 Seismic Evaluation Of Rc Frame With Brick Masonry Infill Walls M. Tech.

Scholar, Assistant Professor, Department Of Civil Engineering, GovindBallabh Pant University Of Agriculture

& Technology, Pant Nagar

VII. Medha Shirvastava1 K.K. Pathak2 Seismic Evaluation Of Rc Building With Various Infill Thickness At

Different Positions Student, Professor,Department Of Civil And Environmental Engineering, Nitttr, Bhopal

(Mp), India

VIII. G.Prasanna Lakshmi*, DrM.HelenSanthi Seismic Evaluation Of Residential Building With Masonry Wall

Using Etabs P.G Student, Professor, Division Of Structural Engineering School Of Mechanical And Building

Sciences Vit University, Chennai 600 127, India 2016

ABOUT AUTHOR SANGEETHA I NAIK is currently M Tech scholar in the Department of Civil Engineering at East West Institute of

Technology, Bengaluru, affiliated to Visvesvaraya Technological University, Belagavi. He has extensively worked

on software “ETABS 9.7.1” developed by Ashraf Habibullah.S.E for Structural Engineering, Earth quake Engineering of

Berkeley, head -quarters, US. His research interests include torsional rigidity and bare frame system in improving

resistance to seismic loads.

ASHWINI G is currently working as an Associate Professor in the Department of Civil Engineering at East West

Institute of Technology, Bengaluru, affiliated to Visvesvaraya Technological University, Belagavi. She has published

Technical papers in National journals in the field of Structural Engineering.

Her research interests include structural dynamics, finite element analysis and earthquake resistant structures. She has

been a part of number of infrastructure, commercial and residential projects during her service in industry.

Documents

SEISMIC EVALUATION OF RC FRAMED STRUCTURE WITH AND … · SEISMIC EVALUATION OF RC FRAMED STRUCTURE WITH AND WITHOUT OPENING IN MASONRY INFILLS SANGEETHA I NAIK 1, ASHWINI G 2. 1Mtech