DOI : 10.17577/IJERTCONV10IS11060
- Open Access
- Authors : Namrata S Naragunkar, Sushma, Sinchana M B, Shwetha K M, Ranjitha P
- Paper ID : IJERTCONV10IS11060
- Volume & Issue : ICEI – 2022 (Volume 10 – Issue 11)
- Published (First Online): 27-08-2022
- ISSN (Online) : 2278-0181
- Publisher Name : IJERT
- License:
This work is licensed under a Creative Commons Attribution 4.0 International License
Response of Building for Different Braces using E-TABS
Namrata S Naragunkar, Sushma, Sinchana M B, Shwetha K M, Ranjitha P
Department of Civil Engineering,
Jain Institute of Technology, Davangere, India
AbstractIndia is developing country, Nowadays our Indian population is increasing day by day. According to some sources our Indian population is reached nearly 138 cores, this rapid increase in population forced engineers to adopt for high rise building. Damage caused by lateral load is need to be control. There are so many methods to control the damage of building by lateral loads, we are adopting one of method, providing the different types of bracings to the building.
In present study, we have used conventional building with 16mx10m along X and Y direction. We carried out the equivalent static linear analysis by using ETABS software, then comparing the results of displacement, storey drift, base shear b\w the bare building and Braced building.
KeywordsBracing, Displacements, Storey Drift, Base shear, E- TABS etc.
I.INTRODUCTION
India is developing country. According to 2020census our Indian population is reached nearly 138,00,00,4385(138 corers). This sudden increase in population and low availability of the land have forced us (engineers) to go for high rise building. Tall building or high rise building are exposed to various forces or load due to various forces the displacement and moments are generated. To avoid these problems we are chosen.
Bracings, to observe the vibrations the devices or any material are placed which is called as Bracings. There are many ways to providing bracings to improve the building performance. There are different types of bracings namely Diagonal Bracing, V Bracing, Inverted V Bracing and X Bracing. The primary function of Bracing is to provide stability and resist lateral load either from diagonal steel members or from concrete core. For bracing frame, to only support vertical loads beams and columns are designed since all the lateral loads are carried by bracings systems. A braced frame is really strong structure subject to lateral load and wind load, frame are generally made by steel structure, which can work effectively both tension and compression.
-
Different types of Bracings
A braced frame is a really strong structural system commonly used in structures subject to lateral loads such as wind and seismic pressure. The members in braced frame are generally made of steel structures and RCC structures which can work effectively both in tension and compression.
Types of bracing system used as follow:
-
Diagonal Bracing
-
V Bracing
-
Inverted V Bracing
-
-
X Bracing
-
Diagonal Bracing: structural component of any building just above it is a diagonal bracing. To add a strength wooden case member or crate member placed in adjacent angle.
-
V Bracing: Two Diagonal members forming a V shape extend downwards from the top two corners of a horizontal members and meet at a centre point on the lower horizontal member its known as V Bracing.
-
Inverted V Bracing: Inverted v bracing are also know as chevron bracing. Two diagonal members forming a V shape extended upwards from the bottom two corners of a horizontal members and meet at a centre point on the upper horizontal member its know as Inverted V Bracing
-
X Bracing: X bracing uses two diagonal members crossing each other. These only need to be resist to tension, one brace at a time acting to resist sideways forces, depending on the direction of loading. As a result, steel cables can also be used for cross- bracing.
II. OBJECTIVE
In this project G+11 story RCC structure is analyzed to reduce the displacement and movement of the structure.
-
To compare the response of high rise building, with and with and without bracing.
-
To determine the displacement, story drift and base shear for bare building.
-
To determine the displacement, story drift and base shear after introduction of the bracing.
-
To analyze the structure for different orientation of column and compare their results.
-
To select the best bracing among Diagonal Bracing, Inverted V Bracing, V Bracing and X Bracing. Types of structure analyzed:
-
III.METHADOLOGY
-
Step by step as per the below procedure:
-
After the study of various literature reviews, we found our project objectives.
-
In this project we are considering G+ 11 stories. The building dimension 16mx10m.
-
Comparing strength and stability of bare building with the braced building.
-
Analyse all models using E-tabs software by applying the selected loads on building as per the IS code book (IS 875).
-
-
-
GEOMETRICAL DATA:
-
Number of stories: G+11
-
Type of building use: Commercial
-
Plane dimension: 16m x 10m
-
Typical story height: 3m
-
Bottom story height: 3m
-
Height of structure: 36m
-
-
MATERIALS USED:
-
Grade of concrete: M25 for slab, M30 for beams and columns.
-
Grade of steel: Fe500
-
Grade of bracing: ISMB500
-
-
LOADING DATA:
-
Dead load:It is defined automatically by software (Table 2, IS875 (part 1) ; 1987)
-
Live load:For commercial building as per (Table, IS875 (part-2), live load is taken as 2KN/m2.
-
Floor finish: 1.5KN/m2.
-
Wall load: 12.42KN\m.
-
-
MODELING AND STRUCTURE
Fig 1: Plan of the model
Fig-2 Unbraced building (3D view)
FIG-3 X Bracing (3D view)
Fig-4 V Bracing (3D view)
Fig-5 Inverted v bracing (3D view)
Fig-6 Diagonal bracing (3D view)
-
RESULT AND DISCUSSION
-
Maximum storey displacement with 1.5(DL+LL+EQX) along X direction.
story
Bare building
Diagonal bracing
V
Bracing
Inverted V
X
Bracing
Base
0
0
0
0
0
Story1
2.603
1.386
1.28
0.988
0.935
Story2
7.386
3.493
3.455
2.793
2.645
Story3
12.749
5.957
5.951
4.978
4.823
Story4
18.247
8.687
8.731
7.508
7.353
Story5
23.705
11.581
11.67
10.264
10.111
Story6
29.008
14.545
14.673
13.135
12.983
Story7
34.046
17.496
17.651
16.026
15.868
Story8
38.698
20.357
20.52
18.85
18.673
Story9
42.828
23.058
23.202
21.538
21.317
Story10
46.278
25.556
25.626
24.027
23.724
Story11
48.843
27.797
27.737
26.298
25.863
Story12
50.255
29.64
29.397
28.25
27.563
Table-1 Maximum storey displacement in X- direction
Fig-7 Maximum storey displacement of the building along X direction.
According to the above graph, bare building shows maximum displacement compare to different braced building in X direction.
Diagonal bracing shows 41.02% lesser displacement then the Bare building. V Bracing shows 41.50% lesser displacement than the bare building. Inverted V Bracing shows 43.78% lesser displacement than the bare building. X bracing shows 45.15% displacement. when compared with other bracings X bracing shows least displacement and more stable.
-
Maximum storey displacement 1.5(DL+LL+EQY) along y- direction
displacement compared to the bare building. V Bracing shows 31.13% lesser displacement compared to the bare building. Inverted V Bracing shows 32.74% lesser displacement compared to the bare building. X Bracing shows 33.07% lesser displacement.
-
Maximum storey drift 1.5(DL+LL+EQX) in X direction.
Story
Bare building
Diagonal Bracing
V
Bracing
X
Bracing
inverted v
Base
0
0
0
0
0
Story1
0.000868
0.000427
0.000453
0.000329
0.000312
Story2
0.001594
0.000727
0.000704
0.000602
0.00057
Story3
0.001788
0.000844
0.000822
0.000733
0.000726
Story4
0.001833
0.000934
0.000911
0.000849
0.000844
Story5
0.00182
0.000986
0.000965
0.000924
0.00092
Story6
0.001768
0.001007
0.000989
0.000963
0.000958
Story7
0.001679
0.000999
0.000985
0.000969
0.000962
Story8
0.001551
0.000963
0.000955
0.000947
0.000935
Story9
0.001377
0.000902
0.000903
0.000901
0.000882
Story10
0.001151
0.000819
0.000833
0.000838
0.000806
Story11
0.000856
0.000723
0.000754
0.000768
0.000716
Story12
0.000471
0.000553
0.000615
0.00065
0.000567
Table-3 Max storey drift of the building in X direction.
4.3
Story
Bare Building
Diagonal Bracing
V
Bracing
Inverted Bracing
X
Bracing
Base
0
0
0
0
0
Story1
2.659
1.748
1.322
1.258
1.321
Story2
7.658
4.573
3.751
3.606
3.869
Story3
13.37
7.885
6.732
6.575
6.913
Story4
19.291
11.534
10.161
9.988
10.343
Story5
25.216
15.389
13.874
13.686
14.013
Story6
31.015
19.329
17.727
17.523
17.796
Story7
36.565
23.244
21.593
21.368
21.574
Story8
41.731
27.032
25.359
25.102
25.236
Story9
46.358
30.599
28.928
28.617
28.677
Story10
50.24
33.872
32.221
31.817
31.797
Story11
53.027
36.729
35.153
34.574
34.475
Story12
54.574
38.986
37.585
36.705
36.522
Table -2 Maximum storey displacement of the building along Y- direction.
Fig-8 Maximum storey displacement of the building along Y- direction.
According to above graph, bare building shows maximum displacement compare to different braced building in Y direction. Diagonal Bracing shows 28.56% lesser
Fig- 9 maximum storey drift of the building in X- direction According to above graph, bare building shows maximum drift compare to different braced building in X direction. Diagonal bracing shows 45.06% lesser drift compared to the bare building. V Bracing shows 46.04% lesser drift compared to the Bare building. V Bracing shows 47% lesser drift compared to the bare building. X Bracing shows 47.67% lesser drift when compared to other bracings.
-
Maximum storey drift 1.5(DL+LL+EQY) in Y direction.
Story
Bare Building
Diagonal Bracing
V
Bracing
Inverted V
Bracing
X
bracing
Base
0
0
0
0
0
Story1
0.00088
0.00057
0.00044
0.00041
0.0004
Story2
0.00166
0.00094
0.0008
0.00078
0.0008
Story3
0.00190
0.00110
0.001
0.0009
0.0010
Story4
0.00197
0.00121
0.00114
0.00113
0.0011
Story5
0.00197
0.00128
0.00124
0.00123
0.0012
Story6
0.00193
0.00131
0.00128
0.00128
0.0012
Story7
0.0018
0.00130
0.00129
0.00129
0.0012
Story8
0.00172
0.00126
0.0012
0.00125
0.0012
Story9
0.00154
0.00119
0.00119
0.0011
0.0011
Story10
0.00129
0.00109
0.00110
0.0010
0.0010
Story11
0.0009
0.00095
0.00098
0.00093
0.0009
Story12
0.00051
0.000752
0.00081
0.00073
0.0006
Table -4 Maximum storey drift of the building in y- direction.
Fig-10 Maximum storey drift of the building in y- direction.
According to above graph, bare building shows maximum drift compare to different braced building in Y direction. Diagonal Bracing shows 33.4% lesser drift, V Bracing shows 34.5% lesser drift, Inverted V Bracing shows 34.7% lesser drift and X Bracing shows 36% lesser drift when compared to the bare building.
Bracings
Fx
Fy
Fz
Mx
My
without
-120.8
-312
56974.96
2.93E+08
-515781
Diagonal
-1863.5
-312
58215.8
298795
-543245
V Bracing
-2023.8
-312
58764.85
301540
-552053
Inverted V
-1899.8
-312
58764.88
301540
-548848
X bracing
-2044.0
-312
59457.43
305703
-558459
-
Base Shear 1.5(DL+LL+EQX) in X- direction: Table : 5 Base shear for different braced building.
Fig: 11 Base shear for different braced building.
The Base shear of the bare building is minimum when compared with braced building. Among the all types of bracing X Bracing shows maximum Base shear.
Bracings
Fz
Mx
My
without
56974.17
294745.7
-492620
Diagonal
58215.8
300953.9
-503174
V Bracing
58764.88
303699.3
-507841
Inverted V
58764.88
303699.3
-507841
X bracing
59457.43
307162.1
-513728
-
Base shear 1.5(DL+LL+EQY) along Y direction. Table :6 Base shear for different braced building.
Fig : 12 Base shear for different braced building.
The Base shear of the bare building is minimum when compared with braced building. Among the all types of bracing X Bracing shows maximum Base shear.
-
Lateral displacement due to Wind Load 1.5(DL+LL+WX) along X direction
Table: 7 Lateral displacement due to wind load along X direction
Story
Bare building
Diagonal bracing
V
Bracing
Inverted V
X
bracing
mm
mm
mm
mm
mm
Base
0
0
0
0
0
Story1
0.643
0.223
0.148
0.14
0.0546
Story2
1.776
0.549
0.479
0.394
0.15366
Story3
3.032
0.934
0.794
0.709
0.27651
Story4
4.335
1.371
1.169
1.087
0.42393
Story5
5.665
1.85
1.591
1.514
0.59046
Story6
7.013
2.36
2.05
1.978
0.77142
Story7
8.374
2.893
2.535
2.47
0.9633
Story8
9.744
3.443
3.037
2.979
1.16181
Story9
11.111
4.001
3.547
3.497
1.36383
Story10
12.446
4.567
4.054
4.013
1.56507
Story11
13.63
5.121
4.558
4.528
1.76592
Story12
14.304
5.569
4.994
4.928
1.92192
Fig :13 Shows the lateral displacement due to wind load along X direction.
According to the above graph, bare building shows maximum displacement compare to different braced building in X direction.
Diagonal bracing shows 61% lesser displacement then the Bare building. V Bracing shows 65.08% lesser displacement than the bare building. Inverted V Bracing shows 65.54% lesser displacement than the bare building. X bracing shows 80.05% displacement. when compared with other bracings X bracing shows least displacement and more stable.
-
Lateral displacement due to Wind load 1.5(DL+LL+WY) along Y direction.
Table:8 Lateral displacement due to Wind load along Y direction.
Story7
0.000454
0.000178
0.000107
0.000167
0.000166
Story8
0.000457
0.000183
0.000128
0.000173
0.000172
Story9
0.000456
0.000187
0.000147
0.000176
0.000175
Story10
0.000445
0.000189
0.000164
0.000177
0.000176
Story11
0.000396
0.000191
0.00018
0.000179
0.000175
Story12
0.000225
0.000149
0.00014
0.000146
0.000133
Story
Bare building
Diagonal bracing
V
bracing
Inverted V
X
bracing
mm
mm
mm
mm
mm
Base
0
0
0
0
0
Story1
0.926
0.45
0.323
0.315
0.085
Story2
2.5
1.101
0.902
0.827
0.34
Story3
4.261
1.865
1.547
1.469
0.761
Story4
6.103
2.725
2.31
2.229
1.339
Story5
7.994
3.66
3.161
3.078
2.042
Story6
9.92
4.65
4.076
3.995
<>2.846 Story7
11.869
5.678
5.034
4.957
3.731
Story8
13.829
6.729
6.017
5.947
4.679
Story9
15.772
7.787
7.006
6.946
5.671
Story10
17.608
8.834
7.981
7.934
6.68
Story11
19.033
9.784
8.877
8.823
7.603
Story12
19.739
10.467
9.574
9.439
8.247
Fig:15 shows the story drift due to wind load along X direction
According to above graph, bare building shows maximum drift compare to different braced building in X direction. Diagonal bracing shows 58.64% lesser drift compared to the bare building. V Bracing shows 60.61% lesser drift compared to the Bare building. V Bracing shows 60.83% lesser drift compared to the bare building. X Bracing shows 62% lesser drift when compared to other bracings.
-
Story drift due to Wind load 1.5(DL+LL+WY) along Y direction.
Fig:14 Shows the displacement along Y direction due to Wind load
According to above graph, bare building shows maximum displacement compare to different braced building in Y direction. Diagonal Bracing shows 46.97% lesser displacement compared to the bare building. V Bracing shows 51.49% lesser displacement compared to the bare building. Inverted V Bracing shows 52.18% lesser displacement compared to the bare building. X Bracing shows 58.21% lesser displacement.
4.9 Storey Drift due to Wind load 1.5(DL+LL+WX) along X direction.
Story
Bare building
Diagonal bracing
Vbracing
Inverted V
X bracing
Base
0
0
0
0
0
Story1
0.000214
0.000073
0.000101
0.000049
0.000047
Story2
0.000378
0.000109
0.000094
0.000111
0.000085
Story3
0.000418
0.000128
0.000042
0.00011
0.000107
Story4
0.000435
0.000146
0.00002
0.00013
0.000128
Story5
0.000443
0.00016
0.000054
0.000146
0.000144
Story6
0.000449
0.00017
0.000082
0.000158
0.000157
Table :9 Story drift along X direction.
Table :10 Story drift along Y direction
Story
Bare building
Diagonal bracing
V
bracing
Inverted V
bracing
X
bracing
Base
0
0
0
0
0
Story1
0.000309
0.000105
0.000148
0.000028
0.000108
Story2
0.000525
0.00017
0.000218
0.000085
0.000193
Story3
0.000587
0.000215
0.000255
0.000143
0.000221
Story4
0.000614
0.000254
0.000287
0.000195
0.000259
Story5
0.00063
0.000285
0.000312
0.000236
0.000288
Story6
0.000642
0.00031
0.00033
0.000269
0.000309
Story7
0.00065
0.000329
0.000343
0.000296
0.000324
Story8
0.000654
0.000343
0.00035
0.000317
0.000332
Story9
0.000648
0.000351
0.000353
0.000332
0.000334
Story10
0.000612
0.000354
0.00035
0.00034
0.00033
Story11
0.000476
0.000322
0.00032
0.000314
0.000308
Story12
0.000235
0.000237
0.000227
0.000215
0.000232
Fig :16 shows the story drift due to wind load along Y direction.
According to above graph, bare building shows maximum drift compare to different braced building in Y direction. Diagonal Bracing shows 45.87% lesser drift, V Bracing shows 46.48% lesser drift, Inverted V Bracing shows 48.08% lesser drift and X Bracing shows 49% lesser drift when compared to the bare building.
-
Base shear for wind load:
Bracings
Fz
Mx
My
without
56974.17
290659.6
-492620
Diagonal
58215.8
296867.7
-503174
V Bracing
58764.88
299613.1
-507841
Inverted V
58764.88
303351.6
-507841
X bracing
59457.43
306814.4
-513728
Table :11 Table show base shear due to wind load.
Fig:17 shows the base shear due to wind load in X direction.
The Base shear of the bare building is minimum when compared with braced building. Among the all types of bracing X Bracing shows maximum Base shear.
-
Base shear due to wind load in Y direction.
Bracings
Fz
Mx
My
without
56974.17
294745.7
-492620
Diagonal
58215.8
300953.9
-503174
V Bracing
58764.88
303699.3
-507841
Inverted V
58764.88
303699.3
-507841
X bracing
59457.43
307162.1
-513728
Table : 12 Base shear due to wind load in Y direction.
-
-
CONCLUSION
From this study, analyzed the variation of the lateral displacement, story drift and base shear along X and Y directions. This present study is concluded with the following conclusions.
-
In ESM for the load combinations 1.5(DL+LL+EQX) and 1.5(DL+LL+EQY). The variation of the lateral displacement of the building is compared with the bare building along X and Y direction. The displacement is minimum in X Braced building and maximum in bare building.
-
The ESM for the load combinations 1.5(DL+LL+WX) and 1.5(DL+LL+WY). The variation of lateral displacement of the building is compared with the bare building along X and Y direction. The displacement is minimum in X braced building and maximum in bare building.
-
The ESM for the load combinations 1.5(DL+LL+EQX) and 1.5(DL+LL+EQY). The variation of the story drift of bare building is compared with different types braced building along X and Y direction. The story drift is maximum in bare building and minimum in X braced building.
-
The ESM for the load combinations 1.5(DL+LL+WX) and 1.5(DL+LL+WY). The variation of the story drift of bare building is compared with different types of braced building along X and Y direction. The story drift is maximum in bare building and minimum in X braced building.
-
The ESM for the load combinations 1.5(DL+LL+EQX) and 1.5(DL+LL+EQY). The variation of the base shear of the bare building is compared with the different types of the braced building along X and Y direction. The base shear is minimum in bare building and maximum in X braced building.
-
The ESm for the load combinations 1.5(DL+LL+WX) and 1.5(DL+LL+WY). The variation of the base shear of the bare building is compared with the different types of the braced building along X and Y direction. The base shear is minimum in bare building and maximum in X braced building.
-
From the overall result the displacement and story drift is minimum in braced building and base shear is maximum in Braced building compare to bare building.
Fig :18 Shows the base shear due to Wind load in Y direction.
The Base shear of the bare building is minimum when compared with braced building. Among the all types of bracing X Bracing shows maximum Base shear.
REFERECES
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