Earthquake Response of Tall Irregular Building by using Different Framing Systems over the Height

IJSRD - International Journal for Scientific Research & Development| Vol. 4, Issue 05, 2016 | ISSN (online): 2321-0613

Earthquake Response of Tall Irregular Building by using Different Framing Systems over the Height Vishwanath Mangi M1 M.Q.Patel2 M.Tech. Student 2Assistant Professor 1,2 Department of Civil Engineering 1,2 BLDEA’s V.P.Dr.P.G. Halakatti College of Engineering & Technology, Vijayapur 1

Abstract— In present days, the tall buildings which are constructed with RCC, steel, and composite materials. Based on the density of materials one can say that the earthquake response of the steel building will be more and the earthquake response of RCC building will be less. The earthquake response of composite material lies in between steel and RCC. Commonly used materials for the construction are RCC and steel. Composite materials are very rarely used for the construction of building. So, present work gives importance on optimization of earthquake response of tall irregular buildings like L, C & H shapes. It can be done by developing different framing systems (RCC, composite, steel) over the height (combined model). In this study, the comparison has been done between combined models and composite models of different shapes.

Key words: Time Period and Frequency, Displacement, Story Drift Ratio, Story Shear I. INTRODUCTION In developed civilization, there are different types of buildings which are stable against earthquake with different techniques, different material &different shapes. In this project, earthquake responses of tall structure with different shapes which are irregular in horizontal plane are studied.

There are many different types of irregular buildings that are constructed, but in this project horizontal irregular building with shapes like L,C & H are studied. These structures are either built with steel, Reinforced Concrete or composite materials.

A. Reinforced Cement Concrete (RCC) Concrete structure is defined as the overall building of structure frames, sections are made up of concrete material.

Reinforcement arrangements are usually designed to resist tensile stresses in some regions of concrete that may cause unacceptable structural failure & cracking. Advanced RCC, it contains materials are made of steel, polymers or substitute composite materials in joining with rebar. RCC may also be stressed permanently, so as to improve the behavior last structure working under the loads. In USA, the strategies are called as post & pre-tensioning.

For ductile, strong &durable construction, development the reinforcement necessary for the accompanying properties like  Relatively higher strength  Higher tensile strain  Great bond to the concrete, irrespective of pH, moisture& similar factors  Thermal compatibility, not causing unacceptable stresses in temperature changing.  Strength in the concrete environment, managed stress& irrespective of corrosion.

B. Steel Structure A structure which is worked by utilizing metal is called steel structure. Steel structures are used for a numerous reasons including living accommodation, work places &storages.

They are arranged into specific types depending on their uses.

A steel structure at first popularity is gained in the mid-20th century. Their uses turned out to become more during 2nd World War &basically extended later the war when steel become more available& due to cost efficiency steel structures are widely accepted. The application range has expanded with improved products materials & design compatibilities of PC supported configuration programming like design software.

C. Composite Building It is a nonspecific term to describe building development including different materials. Construction of composite is regularly utilized as a part of building, aircraft, watercraft, and building& bridge structure development. There are many reasons to utilize composite materials including environment sustainability, aesthetics, and increased strength.

In civil engineering, a composite structure exists when two materials are bound together that they act together as a single unit from of structural point of view. When this happens, it is called composite activity. One normal case includes concrete floor slab supported by steel beams. If the slab is not connected to the beam, then the slab transfers its entire load to the beam and the slab contributes the load conveying ability of the of the beam. In any case, the beam is connected to the slab with studs and then the section of the slab can be assumed to the beam act as positively. As a result, this composite makes a stronger& larger beam than would be provided by the steel beam. The basic designer may compute a changed area as one stage in analyzing the load carry ability of the composite beam.

D. Objectives Following are the objectives 1) Analyzing the tall irregular composite structures i.e., by pushover analysis method to study the earthquake response of the structure.

2) Analyzing the tall irregular combined structures i.e., by pushover analysis method to study the earthquake response of the structure.

3) Irregular shaped buildings with different materials are studied and comparison is made to find out which structure is more stable against earthquake.

II. METHODOLOGY 1) In this study, six models of irregular shapes like L, C & H are modelled in ETabs 9.7.1. In that three models

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Earthquake Response of Tall Irregular Building by using Different Framing Systems over the Height (IJSRD/Vol. 4/Issue 05/2016/313)

are composite structure and other three are combined structure.

2) Pushover analysis is carried out and results of combined structure and composite structure are compared to find out which structure is more stable against earthquake.

III. MODELING AND ANALYSIS In this project six models are studied as described below A. Composite C, H & L Shape Model First three models are composite models which are horizontally irregular shape of C, H & L shape models. In every shape there are 12 floor levels and the overall building structure is built by composite material. In this all columns are built by composite material and all beams are made up of steel. The first three models are named as  Composite C Shape Model (TYPE1)  Composite H Shape Model (TYPE2)  Composite L Shape Model (TYPE3) B. Combined C, H & L Shape Model Other three models are of same shapes,like C, H & Lbut these models are combined model, means the overall floor or height of building is divided as three parts (i.e., h/3, 4 stories in each part). The bottom part of structure is made by Concrete beams and concrete columns, and in middle part of structure is made by composite material. In this columns are composite and beams are steel. The top part of structure made up of steel.  Combined C Shape Model (TYPE1.1)  Combined H Shape Model (TYPE2.1)  Combined L Shape Model (TYPE3.1) 1) Structural Models In this study, there are six models with eleven stories. The Area of the each floor is i.e. 672sqm. The models are 3mof same story height & mass distribution is uniform. Structural models plans are as shown below  No of storey = G+11  Story height = 3m  Spacing in X & Y direction =4M

Fig. 3.4: Elevation of Composite models

Fig. 3.5: Elevation of Combined models 2) Input Details of Models Below tabular column lists the details of Beams, Columns & Slab for all models Floor Models COL Beam Slab Levels 8 TO 11 TYPE (C)

4 TO 7 G To 3 8 TO 11

TYPE2 (H)

4 TO 7 G To 3 8 TO 11

TYPE3 (L)

4 TO 7 G To 3 8 TO 11

TYPE1.1 (C)

4 TO 7 G To 3 8 TO 11

Fig. 3.1: C-SHAPE Plan

Fig. 3.2: H-SHAPE Plan

TYPE 2.1 (H)

4 TO 7 G To 3 8 TO 11

TYPE 3.1 (L)

Fig. 3.3: L-SHAPE Plan

4TO 7

C+ISMB4 50 C+ISMB4 50 C+ISMB4 50 C+ISMB4 50 C+ISMB4 50 C+ISMB4 50 C+ISMB4 50 C+ISMB4 50 C+ISMB4 50 ISMB450 C+ISMB4 50 C400X60 0 ISMB450 C+ISMB4 50 C400X60 0 ISMB450 C+ISMB4 50 C400X60 0

ISMB300

125

ISMB300

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ISMB300

125

ISMB300

125

ISMB300

125

ISMB300

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ISMB300

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ISMB300

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ISMB300

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ISMB350

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B200X60 0 ISMB350 ISMB350 B200X60 0 ISMB350 ISMB350

B200X60 0 Table 1: Details of Models 3) Seismic Details Detail Value R(response reduction factor) 5(SMRF) G To 3

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125 125 125 125 125 125 125

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Earthquake Response of Tall Irregular Building by using Different Framing Systems over the Height (IJSRD/Vol. 4/Issue 05/2016/313)

I( Importance factor) 1 Z( Zone-III) .16 Sa/G( Soil type II) Type2 Table 2: Seismic Details Grade of Grade of Structural Concrete in steel in Elements All Model All Model Beam M25 Fe500 Column M45 Fe500 Slab M25 Fe500 Table 3: Material Property IV. RESULTS In this chapter, the results of all six types of analyzed models are shown in the Table 4.1 to 4.17 and graph 4.1 and these results are discussed below. For analysis of each model the parameters considered are Time period, Frequency, storey drift, Storey displacement and storey shear.

1) Comparing the Displacement of T3.1 Model with Other Models Parameter Mo Values T3.1 Values % of s dels in mm in mm Reduction T1 454 302 33.48 T2 708 302 57.34 DISPLACE T3 633 302 52.29 MENT T1.1 343 302 11.95 T2.1 344 302 12.20 Table 4.1: Comparing Pushover Displacement B. Capacity Spectrum For all models the capacity curve are drawn & is shown in Figs 4.2 It has been observed that, hinges started forming in beams first, on subsequent push to building. At first hinges are in stage B-IO &this manner continuing to stage IO-LS & LS-CP.

A. Pushover Curves For composite and combined models the pushover curves are as shown below. The graph shows displacement & base shear along X& Y axis respectively.

Type-1

Type-1

Type-2

Type-3

Type-3

Type-2

Type-1.1

Type-1.1

Type-2.1

Type-3.1 Fig. 4.2: Graph 1) Comparison of Performance Point Parameters Type-2.1 Models T–1

Fig. 4.1: Graph Spectral acceleration(Sa) 0.105

Type-3.1 Base Shear V(kN) 9653.98

Spectral Displacement Sd mm 248

Roof displacement (mm) 329

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Earthquake Response of Tall Irregular Building by using Different Framing Systems over the Height (IJSRD/Vol. 4/Issue 05/2016/313)

T- 2 T- 3 T- 1.1 T- 2.1 T- 3.1

0.098 9113.12 260 348 0.102 8966.06 255 318 0.082 7428.9 218 291 0.08 7204.88 213 288 0.085 7220.99 201 261 Table 4.2: Comparing performance point parameters of Capacity spectrum T2.1 3.564 3.976 10.37 C. Time Period and Frequency Table 4.4: Comparing Time Period values Time period, T value depends upon the building mass & The above table shows that Time period values comparing flexibility; If flexibility is more, then the period is longer the model T3.1 with other models. It can be seen that Model and mass is more, then period is longer.

T1, T2, T3, T1.1 & T2.1 has 23.633%, 27.48%, 25.22%, In model TYPE 3.1 combined L shape model, time 6.81% &10.37% respectively less values when compares period is maximum. with model T3.1 In model TYPE 2 composite H shape model, time period is minimum D. Frequency It is observed that model TYPE 3.1 compared to Frequencies of all models obtained in ETabs are listed other models. Therefore model TYPE 3.1 combined L shape below building has more mass & flexibility.

Frequency in Hz Time period of each of the six models are recorded Modes T-1 T-2 T-3 T-1.1 T-2.1 T-3.1 below 1 0.329 0.346 0.336 0.269 0.280 0.251 Time period in sec Modes 2 0.373 0.354 0.359 0.485 0.475 0.363 T–1 T–2 T–3 T-1.1 T-2.1 T-3.1 3 0.400 0.377 0.377 0.490 0.481 0.378 1 3.036 2.883 2.973 3.705 3.564 3.976 4 1.071 0.650 1.091 0.753 0.795 0.586 2 2.678 2.822 2.778 2.058 2.102 2.750 5 1.270 1.120 1.216 1.041 1.084 0.977 3 2.497 2.646 2.650 2.040 2.077 2.642 6 1.301 1.227 1.252 1.360 1.328 1.055 4 0.933 1.537 0.916 1.327 1.256 1.705 7 1.981 1.275 2.012 1.438 1.433 1.180 5 0.787 0.892 0.822 0.959 0.922 1.023 8 2.505 2.056 2.357 1.485 1.516 1.471 6 0.768 0.814 0.798 0.735 0.752 0.947 9 2.618 2.468 2.412 1.885 1.913 1.831 7 0.504 0.784 0.496 0.695 0.697 0.846 10 3.114 2.490 3.152 2.110 1.979 1.903 8 0.399 0.486 0.424 0.673 0.659 0.679 11 4.137 3.213 3.831 2.330 2.243 1.993 9 0.381 0.405 0.414 0.530 0.522 0.546 12 4.258 4.111 3.972 2.418 2.307 2.191 10 0.321 0.401 0.317 0.473 0.505 0.525 Table 4.4: Frequency results 11 0.241 0.311 0.260 0.429 0.445 0.501 12 0.234 0.243 0.251 0.413 0.433 0.456 Table 4.3: Time Period

Table 4.3: Frequency results From above graph one can see that, the frequency increases with respect to the increase in number of modes.  At the 1st mode, the frequency of T2model is maximum and minimum is T3.1 model.  At the 2nd mode, the frequency of T1.1model is maximum and minimum is T2 model.  At the 3rd mode, the frequency of T2.1model is maximum and minimum is T3.1 model.

1) Comparing Frequency values with Model T3.1 in below table Frequency comparison of T3.1 model with other models.

Parame Mod Values T3.1 Values % of ters els in Hz in Hz Reduction T1 0.329 0.251 23.63 Frequen T2 0.346 0.251 27.48 cy at 1st T3 0.336 0.251 25.22 Mode T1.1 0.269 0.251 6.811 

Fig. 4.2: Graph for time period From above graph one can see that, the time period decreases as the number of modes increases.  At the 1st mode, the time period of T3.1 model is maximum and minimum is T2 model.  At the 2nd mode, the time period of T2 model is maximum and minimum is T1.1 model.  At the 3rd mode, the time period of T3.1model is maximum and minimum is T2.1 model.

1) Comparing Time Period Values with Model T3.1 Parameter Mod Values T3.1 Values % of s els in sec in sec Increment T1 3.036 3.976 23.63 Time T2 2.883 3.976 27.48 period at 1st T3 2.973 3.976 25.22 Mode T1.1 3.705 3.976 6.81

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Earthquake Response of Tall Irregular Building by using Different Framing Systems over the Height (IJSRD/Vol. 4/Issue 05/2016/313)

T2.1 0.280 0.251 10.37 Table 4.5: Comparing Frequency values The above table shows that frequency values comparing the model T3.1 with other models. It can be seen that Model T1, T2, T3, T1.1 & T2.1 has 23.633%, 27.48%, 25.22%, 6.81% &10.37% respectively less values when compared with model T3.1

structure is reduced in model TYPE 3.1, due to this displacement reduced.

By observing displacement of all the models, in the TYPE 3.1 displacement is lesser than all other models. Here a displacement is more in upper stories and lowest in bottom stories.

In the model TYPE 3.1 displacement is less than the other models. It means that  Strength reduction is less.  TYPE 3.1 models Structure is more stable than other models.

The results were checked for Pushover in Xdirection.

1) Displacement of Pushover in X-Direction Displacement of Pushover in X- direction is below as shown in table

E. Displacement From Table, it can be seen that, the displacement of structure is reduced in model TYPE3.1. From results all the models, the minimum displacement is in model TYPE 3.1 & maximum in model TYPE 2. The tables & graphs show that consistently displacement is increasing over stories height.

As shown by this, displacement decreases in structure because of decreases of acceleration & velocity of structure and increasing in stiffness. So that response of Displacement(mm) of Pushover in X-direction Storey Level T-1 T-2 T-3 T-1.1 T-2.1 T-3.1 11 450.755 519.325 392.932 319.350 270.689 268.378 10 437.038 508.971 388.928 313.476 266.140 262.982 9 418.356 494.823 382.924 302.977 258.331 253.609 8 392.815 474.159 372.695 285.868 244.520 238.499 7 35.069 439.121 352.888 248.396 217.317 208.827 6 316.431 391.754 319.810 218.760 191.753 184.667 5 265.569 334.359 276.326 185.931 163.264 157.402 4 208.728 269.401 224.818 148.591 130.565 125.965 3 149.543 200.121 168.269 106.015 92.536 89.433 2 92.626 130.491 110.416 61.860 53.065 51.614 1 43.158 64.680 54.979 24.747 20.707 20.362 BASE 0 0 0 0 0 0 Table 4.6: Displacement of stories T2 519.325 268.378 48.32 ent of pushover T3 392.932 268.378 31.69 in XT1.1 319.350 268.378 15.96 direction T2.1 270.689 268.378 0.85 Table 4.7: Comparing displacement of Pushover i From above table it shows the model T3.1 is less displacement than other models. Displacement of pushover in X-direction, it has been found that the reduction percentage of Model T1, T2, T3, T1.1 & T2.1 has 40.46%, 48.32%, 31.69%, 15.96% &0.85% respectively, when compared to the model T3.1.

Fig. 4.4: Graph for story level vs Displacement From above graph, one can see that the displacement of T3.1 model is less than other model.

-At the bottom stories, the reduction of the displacement of T3.1 model is 3.5-68.5% when compared to other models.

-At the middle stories, the reduction of the displacement of combined model is 2.4-52.9% when compared to other models.

-The reduction of the displacement of combined model at top stories is .85-48.3% when compared to other models.

2) Comparing displacement of Pushover in X – direction Displacement comparison of model T3.1 with other models T3.1 % of Parameter Mode Values in Values Reducti s ls mm in mm on T1 450.755 268.378 40.46 Displacem

F. Story Drift Ratio The displacement of one level regarding the following above level or underneath. The building may get breakdown because of various reactions. For example at adjacent levels, for instance, curvatures, arches, at all overall levels and rotations, for instance, inside story drifts.

Particular stories may show excessive lateral displacement. So it can be concluded that by reducing the structure story drift, the probability of building collapse can be reduced. That is model TYPE 3.1 can be decreases earth quake reaction of structure.

By observing that in model TYPE 3.1 the story drifts ratio of all stories is different and less than the other all models. Here as thought to be clear the story drift extent is low in base stories, ultimately reduces towards the upper stories & high at the middle stories.

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Earthquake Response of Tall Irregular Building by using Different Framing Systems over the Height (IJSRD/Vol. 4/Issue 05/2016/313)

    Fig. 4.5: Graph for Storey Drift Ratio in X- direction

From above graph one can see that, the story drift ratio increases upto middle stories further decreases towards upper stories.

At the bottom stories, the story drift ratio of T3.1 model is minimum and maximum is T2 model.

At the middle stories, the story drift ratio of T3.1 model is minimum and maximum is T3 model.

At the top stories, the story drift ratio of T1.1model is minimum and maximum is T2model.

G. Story Shear As it shows in below table the minimum story shear is in TYPE3 & maximum story shear in TYPE 1. Storey shear of all models are listed with their story height

Fig. 4.6: Graph for Storey Drift Ratio in Y- direction Story Level 12 11 10 9 8 7 6 5 4 3 2 1

T-1 -1405.14 -3536.49 -5277.98 -6672.14 -7757.56 -8572.84 -9157.63 -9549.11 -9785.49 -9906.08 -9949.47 -9952.08

Story Shear in kN T-2 T–3 T - 1.1 -470.79 -82.51 -870.93 -1183.08 -203.96 -2175.79 -1766.16 -303.39 -3243.92 -2232.94 -382.99 -4098.98 -2596.36 -444.96 -4799.73 -2869.32 -491.51 -5352.84 -3064.76 -524.82 -5748.84 -3195.58 -547.1 -6013.9 -3274.73 -560.54 -6186.92 -3315.11 -567.35 -6274.75 -3329.65 -569.76 -6306.22 -3330.52 -569.71 -6308.04 Table 4.8: Story Shear

Fig. 4.7: Graph for story level vs Storey Shear From above graph one can see that, the story shear increases from the top stories towards lower stories.  At the bottom middle and top stories, the story shear of T2model is minimum and maximum is T1 model.

V. DISCUSSION OF MODELS The present study discuses the seismic response of tall horizontal irregular building by using different framing system over the height of the building. These obtained results will be mainly based on the configuration of RCC, steel and composite materials.

T - 2.1 -561.18 -1401.11 -2088.67 -2639.1 -3090.67 -3447.44 -3702.88 -3873.88 -3986.46 -4043.68 -4064.28 -4065.61

T - 3.1 -772.35 -1895.32 -2814.56 -3550.45 -4151.31 -4624 -4962.42 -5188.95 -5338.92 -5415.38 -5442.83 -5444.55

A. Comparison of all models 1) Frequency and Time Period Time period is inversely proportional to frequency. If lower the time period then Higher the frequency and vice versa.

From fig 4.1time period value is high in TYPE 3.1 and lower in TYPE 2 .So from this when compared to other models with TYPE 3.1 is more stable.

2) Displacement When Combined L shape (TYPE 3.1) model is compared with other types of models it shows that, t-3.1 model has less earthquake reaction.

3) Drift Ratio When compares model TYPE 3.1 to other types models, It shows that the model TYPE 3.1has shown low Storey drift near middle stories.

4) Storey Shear The storey shear is high in TYPE 1model and lower in TYPE 3 model.

As one can see from above results, there is a more reduction of earthquake response in combined models when compared to composite models. As the combined model consists of various materials over the height like RCC, composite & steel. Based on the materials one can say that

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Earthquake Response of Tall Irregular Building by using Different Framing Systems over the Height (IJSRD/Vol. 4/Issue 05/2016/313)

the earth quake response of steel will be more, earth quake response of RCC will be less and in between these two there will be a composite material. So combining all these materials in single building over the height of a building will reduce the earth quake response.

VI. CONCLUSION A. General The present study was intended to concentrate on the seismic tremor reaction of different framing system over the height of the building. The fundamental destinations of the project are expressed in the one section. The study purpose is to optimize and compare the earth quake response of tall irregular composite building with tall irregular combined (different framing system over the building height) building, which provides adequate energy dissipation.

B. Conclusions 

It has given an idea how the combined model acts in the inelastic regime.  From pushover curve, the displacement of combined L shape model (T3.1) is less than other models. The displacement of T3.1 model is reduced by 11.95% to 57.34% when compared to other models (shown in Table No: 4.1).  The displacement at the performance point (from capacity spectrum) of combined L shape model (T3.1) is less than the other models. The percentage reduction in displacement of T3.1 model is 9.3% to 25% when compared to other models (shown in Table No: 4.2).  At performance point in combined L shape model (T3.1), hinges were in B-IO range, overall performance of building is said to be yield state to immediate occupancy.  From time period, the displacement at the performance point of T3.1 model is less than the other models. The percentage of reduction in displacement of T3.1 model is 9.3% to 25% when compared to other models(shown in Table No: 4.3).  The time period in T3.1 model is more when compared to other model (shown in Table No: 4.4).  The frequency at in T3.1 model is less when compared to other model (shown in Table No: 4.5).  From displacement graph, T3.1 model displacement is less than the other models. The T3.1 model displacement is reduced by 1% to 48% when compared to other models (shown in Table No: 4.6).

So in present study the various materials like RCC, composite & steel are combined over the height and it is seen that the earth quake response of this type of models is better than the composite models.

From this study one can conclude that the best shape of tall structure is L shape. Further, earthquake response of combined L shape is optimal when compared to other shapes (C, H). The worst earthquake response is seen in H shape tall structure.

irregular combined (different framing system over the building height) building, by doing Time history analysis to assess the exact response.

2) Compare the earth quake response of tall irregular composite building with tall irregular combined (different framing system over the building height) building, by doing Response spectrum analysis.

ACKNOWLEDGEMENT It is our pleasure to express our heartfelt thanks to our friendly Prof. M. Q. PATEL for their supervision and guidance, which enabled us to understand and develop this project.

We are indebted to Dr V. P. Huggi, P. G. Halkatti College of Engineering, Bijapur, for his constant encouragement and support and the HOD of civil department Prof. S. S. Angadi for their abundant support to our project.

I am also thankful to the staff, Civil Engineering Department, for providing all necessary help during the project work.

Lastly, we take this opportunity to offer our regards to all of those who have supported us directly or indirectly in the successful completion of this project work.

REFERENCES [1] “Seismic Analysis And Design Of Vertically Irregular Rc Building Frames”, (2013) by BiswobhanuBhadra & Ankesh Sharma [2] “Push Over Analysis Of Tall Building With Soft Stories At Different Levels”(2013)ByProf. M. R. Vyawahare, Rahiman G. Khan [3] A Parametric Study Of Multy-Storey R/C Buildings With Horizontal Irregularity (2014) By Krishna Murari, R.K Goliya,Dr. A. K Mullick,Himanshu Gaur (2014) [4] “Optimum Sesmic Response of Tall Buildings” (2014) BySajeet S.B2, B.K, Amarnath K, Raghu Prasad1, [5] “Earth Quake Response Of Different Shapes Of Mivan Wall Tall Buildings” (2015) By Supreeth S Gowda, Sajeet.S.B, [6] “Optimisation Of Earth Quake Response Of Tall Building By Using Different Framing Systems Over The Height” (2015) By Shashinag N N, Sajeet.S.B [7] ISo875 – Part I – 1987, “Code Practice for design Loads For buildings and structures. Part-1 Dead Load- unit weights of building materials and stored materials”

C. Scope for Future Studies It is suggested that scope for future studies 1) Analyze the earth quake reaction tall horizontal irregular shape of composite building with tall

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