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IJSTE - International Journal of Science Technology & Engineering | Volume 2 | Issue 01 | July 2015 ISSN (online): 2349-784X
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195
Behavior of a Multistoried Building with and
without infill Walls under Seismic Forces using
STAAD.PRO
K. Satya Narasimha Rao
M. Tech Student Anirudh Gottala
M. Tech Student
Department of Civil Engineering Department of Civil Engineering
Andhra University College of Engineering Andhra University College of Engineering
Dr. Shaik Yajdani
Assistant Professor
Department of Civil Engineering
Andhra University College of Engineering
Abstract
The effect of masonry infill panel on the response of RC frame subjected to seismic action is widely recognized and has been
subject of numerous experimental investigations, while several attempts to model it analytically have been reported. In
analytically analysis infill walls are modelled as equivalent static approach there are various formulae derived by research
scholars and scientist for width of modelling. Infill behaves like compression between column and beam and compression forces
are transferred from one node to another. In this study the effect of masonry walls on high rise building is studied. Static analysis
on high rise building with different arrangement is carried out. For the analysis G+9 R.C.C framed building is modelled. The
width is calculated by using equivalent static method. Various cases of analysis are taken. All analysis is carried out by software
STAAD-PRO. Axial Force, Shear Force, Storey drift, Nodal displacement, bending moment is calculated and compared for all
models. The results show that infill walls reduce displacement, time period and increase base shear. So it is essential to consider
the effect of masonry infill for the seismic evaluation of moment resisting reinforced concrete frame.
Keywords: RCC Framed Buildings, In Filled Walls, High-Rise Building, Displacement
________________________________________________________________________________________________________
I. INTRODUCTION
It has always been a human aspiration to built earthquake resistant structures. The reinforced cement concrete moment resisting
frames in filled with unreinforced brick masonry walls are very common in India and in other developing countries.
Masonry is a commonly used construction material in the world for reason that includes accessibility, functionality, and cost.
The primary function of masonry is either to protect inside of the structure from the environment or to divide inside spaces.
Normally considered as architectural elements. Engineer's often neglect their presence. Because of complexity of the problem,
their interaction with the bounding frame is often neglected in the analysis of building structures, When masonry in fills are
considered to interact with their surrounding frames, the lateral load capacity of the structure largely increases.
This assumption may lead to an important inaccuracy in predicting the response of the structure. This occurs especially when
subjected to lateral loading. Role of infill's in altering the behavior of moment resulting frames and their participation in the
transfer of loads has been established by decades of research. The survey of buildings damaged in earthquakes further reinforces
this understanding. The positive aspects of the presence of never the less, it may be appropriate to neglect their presence and
declare the resulting design as conservative.
Observed infill induced damage in buildings in the past earthquakes exposes the shortcomings of the current bare frame
approach. In buildings, the ordinarily occurring vertical loads, dead or live, do not much of a problem, but the lateral loads due to
wind or earthquake tremors are a matter of great concern and need special consideration in the design of buildings. These lateral
forces can produce the critical stress in a structure, set up undesirable vibrations and in addition, cause lateral sway of the
structure which can reach a stage of discomfort to the occupants.
In many countries situated in seismic regions, reinforced concrete frames are in filled fully or partially by brick masonry.
Although the infill panels significantly enhance both the stiffness and strength of the frame, their contribution is often not taken
into account because of the lack of knowledge of the composite behavior of the frame and the infill. Infill wall can be modeled in
several forms such as creating a plate element with infill walls properties using stad.pro etc.
For new buildings, infill wall is modeled and designed to provide high rigidity. Also older buildings are rehabilitated with
infills that are compatible with the original frame work. Studies found that infill fails in two main ways, Shear failure and Corner
crushing. The variability of the mechanical properties of infill panels, depending on both the mechanical properties of their
Behavior of a Multistoried Building with and without infill Walls under Seismic Forces using STAAD.PRO (IJSTE/ Volume 2 / Issue 01 / 035)
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196
materials and the construction details, introduces difficulty in predicting the behavior of infill panels. Additionally, the overall
geometry of the structure i.e., number of bays and stories, aspect ratio of infill panels and the detailing of the reinforced concrete
members are aspects that should be considered.
The location and the dimensions of openings play also an important role in the evaluation of the strength and stillness of the
infill panels. Despite the aforementioned cases of undesired structural behavior, field experience, analytical and experimental
research have demonstrated that he beneficial contribution of the infill walls to the overall seismic performance of the building,
especially when the latter exhibits limited engineering seismic resistance.
In fact, infill panels through their in-plane horizontal stiffness and strength decrease the storey drift demand, and increase the
storey lateral force resistance respectively, while their contribution to the global energy dissipation capacity is significant, always
under the assumption that they are effectively confined by the surrounding frame.
II. METHODS OF ANALYSIS
Code-based Procedure for Seismic Analysis A.
Main features of seismic method of analysis based on Indian standard 1893(Part 1):2002 are described as follows
Equivalent Static Lateral Force Method
By IS code method for Static analysis B.
By STAAD PRO software Method-for with and without infill walls both. C.
Equivalent Static Analysis: 1)All design against seismic loads must consider the dynamic nature of the load. However, for simple regular structures, analysis
by equivalent linear static methods is often sufficient. This is permitted in most codes of practise for regular, low-to medium-rise
buildings. It begins with an estimation of base shear load and its distribution on each story calculated by using formulas given in
the code. Equivalent static analysis can therefore work well for low to medium-rise buildings without significant coupled lateral-
torsional effects, are much less suitable for the method, and require more complex methods to be used in these circumstances.
III. MODELLING AND ANALYSIS
For the analysis of multi storied building following dimensions are considered which are elaborated below. In the current study
main goal is to compare with and without infill walls (Rectangular) building.
Static and Dynamic Parameters: A.
Design Parameters: Here the Analysis is being done for G+9 (rigid joint regular frame ) building by computer software using STAAD-Pro.
Design Characteristics: The following design characteristic are considered for Multistory rigid jointed plane frames Table - 1
Design Data of RCC Frame Structure
S.No Particulars Dimension/Size/Value
1 Model G+9
2 Seismic Zone II
3 Floor height 3 m
4 Plan size 23.15 x 14.99 m
5 Size of columns 0.6 x 0.6 m
6 Size of beams 0.3 x 0.45 m
7 Walls 1) External Wall =0.23 m
2) Internal Wall =0.115 m
8 Thickness of slab 150 mm
9 Type of soil Type-II, Medium soil as per IS-1893
10 Material used Concrete M-30 and Reinforcement
Fe-415
11 Static analysis Equivalent Lateral force method
12 Earthquake load as per IS-1893-2002
13 Specific weight of RCC 25 KN/m2
14 Specific weight of infill 20 KN/m2
15 Software used STAAD-Pro for both With and Without infill walls
Table - 2
Zone Categories
Seismic Zone II III IV V
Behavior of a Multistoried Building with and without infill Walls under Seismic Forces using STAAD.PRO (IJSTE/ Volume 2 / Issue 01 / 035)
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197
Seismic intensity Low Moderate Severe Very Severe
Z 0.10 0.16 0.24 0.36
Fig. 1: Plan of Regular Building
Fig. 2: 3-D Model of Regular Building
Behavior of a Multistoried Building with and without infill Walls under Seismic Forces using STAAD.PRO (IJSTE/ Volume 2 / Issue 01 / 035)
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Fig. 3: 3-D Model of Regular Building (With Sections)
Fig 4: 3-D Model of Infill Walls Building
Behavior of a Multistoried Building with and without infill Walls under Seismic Forces using STAAD.PRO (IJSTE/ Volume 2 / Issue 01 / 035)
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Fig. 5: Earthquake Loading
Fig. 6: Deflection Diagram (Without Infill Walls)
Fig. 7: Deflection Diagram (With Infill Walls)
Behavior of a Multistoried Building with and without infill Walls under Seismic Forces using STAAD.PRO (IJSTE/ Volume 2 / Issue 01 / 035)
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IV. RESULTS AND DISCUSSIONS
The above RCC frame structure is analyzed both with and without infill walls and the results are compared for the following
three categories namely Shear Force, Storey-Drift, Axial Force, Displacements and Moment at different nodes and beams and the
results are tabulated as a shown below.
Comparison of Bending Moment for Beams A.
Table - 3
Comparison of Bending Moment
BEAM NUMBER STOREY WITH INFILL(KN-m) WITHOUT INFILL(KN-m)
1228 10 43.46 67.8
1110 9 52.02 137.4
992 8 66.5 162.33
874 7 78.59 184.13
756 6 88.23 200.9
638 5 95.3 212.7
520 4 99.89 219.9
402 3 101.89 222.26
284 2 105.56 226.52
166 1 107.3 230.42
Fig. 8: Comparison of bending moment of with and without infill walls
Comparison of Storey-Drift for both with and without infill walls B.
Table 4 Comparison of Storey-Drift
STOREY HEIGHT WITH INFILL WALL
(DRIFT)(mm)
WITHOUT INFILL WALL
(DRIFT)(mm)
30 1.898 2.625
27 2.59 4.096
24 3.159 5.517
21 3.597 6.681
18 3.905 7.55
15 4.089 8.144
12 4.158 8.46
9 4.095 8.468
6 3.805 7.879
3 2.903 5.857
0 0 0
Behavior of a Multistoried Building with and without infill Walls under Seismic Forces using STAAD.PRO (IJSTE/ Volume 2 / Issue 01 / 035)
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Fig. 9: Comparison of Storey-Drift between with and without infill walls
Comparison of Displacement for both with and without infill walls C.
Table - 5
Comparison of Displacement(+X)
STOREY HEIGHT WITH INFILL WALL
(DISPLACEMENT)(mm)
WITHOUT INFILL WALL
(DISPLACEMENT)(mm)
30 34.755 66.305
27 32.852 63.680
24 30.267 59.584
21 27.108 54.067
18 23.511 47.386
15 19.606 39.835
12 15.517 31.691
9 11.359 23.223
6 7.264 14.755
3 3.459 6.879
0 0.556 1.022
Fig. 10: Comparison of Displacement(+X) between with and without infill walls
Comparison of Shear Force for both with and without infill walls D.
Table 6 Comparison of Shear Force
STOREY HEIGHT WITH INFILL WALL
(SHEAR FORCE)(KN)
WITHOUT INFILL WALL
(SHEAR FORCE)(KN)
Behavior of a Multistoried Building with and without infill Walls under Seismic Forces using STAAD.PRO (IJSTE/ Volume 2 / Issue 01 / 035)
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30 430.054 643.528
27 734.80 1255.30
24 978.776 1745.06
21 1168.71 2126.36
18 1311.38 2412.76
15 1413.53 2617.81
12 1481.91 2755.08
9 1523.277 2838.12
6 1544.38 2880.49
3 1551.98 2895.742
0 1552.813 2897.42
Fig. 11: Comparison of Shear Force between with and without infill walls
Comparison of Axial Force for both with and without infill walls E.
Table 7 Comparison of Axial Force
Column number with infill walls(KN) without infill walls(KN)
591 475876 893943
709 370121 717686
827 272612 544221
945 185768 375775
1063 112095 214650
1181 54272 63377
Fig. 12: Comparison of Axial force between with and without infill walls
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Nodal Displacements in (1-G-H) Frame: F.
Table 8
Nodal Displacements in (1-G-H) Frame
Node L/C X-Trans mm Y-Trans mm Z-Trans mm RESULTANT (mm)
6 SEISMIC LOADS 0.653 -0.174 0.069 0.679
DEAD LOAD -0.001 -0.152 -0.006 0.152
SEISMIC+DEAD -0.981 0.033 -0.113 0.988
94 SEISMIC LOADS 4.526 -0.4 0.463 4.567
DEAD LOAD -0.008 -0.437 -0.043 0.439
SEISMIC+DEAD -6.8 -0.054 -0.76 6.842
138 SEISMIC LOADS 9.766 -0.536 0.974 9.829
DEAD LOAD -0.031 -0.695 -0.088 0.701
SEISMIC+DEAD -14.696 -0.237 -1.593 14.784
182 SEISMIC LOADS 15.387 -0.63 1.515 15.474
DEAD LOAD -0.057 -0.923 -0.141 0.936
SEISMIC+DEAD -23.165 -0.44 -2.483 23.302
226 SEISMIC LOADS 21.002 -0.696 2.052 21.114
DEAD LOAD -0.085 -1.122 -0.199 1.142
SEISMIC+DEAD -31.631 -0.639 -3.376 31.817
270 SEISMIC LOADS 26.399 -0.738 2.568 26.534
DEAD LOAD -0.117 -1.29 -0.26 1.321
SEISMIC+DEAD -39.773 -0.828 -4.242 40.008
314 SEISMIC LOADS 31.398 -0.757 3.045 31.555
DEAD LOAD -0.151 -1.427 -0.323 1.471
SEISMIC+DEAD -47.324 -1.006 -5.053 47.603
358 SEISMIC LOADS 35.816 -0.754 3.468 35.991
DEAD LOAD -0.186 -1.534 -0.386 1.592
SEISMIC+DEAD -54.003 -1.17 -5.782 54.325
402 SEISMIC LOADS 39.457 -0.73 3.823 39.648
DEAD LOAD -0.221 -1.608 -0.445 1.683
SEISMIC+DEAD -59.516 -1.317 -6.403 59.874
446 SEISMIC LOADS 42.148 -0.692 4.1 42.352
DEAD LOAD -0.263 -1.651 -0.492 1.742
SEISMIC+DEAD -63.616 -1.437 -6.889 64.004
490 SEISMIC LOADS 43.917 -0.665 4.305 44.133
DEAD LOAD -0.341 -1.662 -0.506 1.77
SEISMIC+DEAD -66.387 -1.495 -7.217 66.795
Column End Forces in (1-G-H) Frame: G.
Table 9 Column End Forces in (1-G-H) Frame
COLUMN L/C Node Shear-Y (KN) Shear-Z (KN) Moment-Y
(KN-m)
Moment-Z
(KN-m)
C949 SEISMIC LOADS 357 42.898 -0.624 0.115 44.624
401 -42.898 0.624 1.756 84.07
DEAD LOAD 357 8.241 -1.832 2.725 12.302
401 -8.241 1.832 2.77 12.422
SEISMIC +DEAD 357 -51.985 -1.812 3.915 -48.484
401 51.985 1.812 1.522 -107.472
C950 SEISMIC LOADS 358 21.259 -1.955 1.302 10.768
402 -21.259 1.955 4.564 53.011
DEAD LOAD 358 8.79 6.059 -8.918 13.169
402 -8.79 -6.059 -9.259 13.202
SEISMIC +DEAD 358 -18.704 12.022 -15.331 3.602
402 18.704 -12.022 -20.735 -59.713
C1067 SEISMIC LOADS 401 29.688 0.061 -0.722 22.379
445 -29.688 -0.061 0.54 66.684
DEAD LOAD 401 8.485 -1.834 2.685 12.352
445 -8.485 1.834 2.817 13.104
SEISMIC +DEAD 401 -31.804 -2.842 5.111 -15.041
445 31.804 2.842 3.416 -80.371
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C1068 SEISMIC LOADS 402 14.104 -1.022 -0.301 -3.271
446 -14.104 1.022 3.368 45.583
DEAD LOAD 402 9.251 6.245 -8.81 13.197
446 -9.251 -6.245 -9.924 14.556
SEISMIC +DEAD 402 -7.279 10.901 -12.764 24.702
446 7.279 -10.901 -19.937 -46.54
C1185 SEISMIC LOADS 445 14.471 0.199 -0.561 3.179
489 -14.471 -0.199 -0.036 40.233
DEAD LOAD 445 8.09 -1.752 2.005 11.305
489 -8.09 1.752 3.25 12.965
SEISMIC +DEAD 445 -9.571 -2.926 3.849 12.189
489 9.571 2.926 4.929 -40.902
C1186 SEISMIC LOADS 446 0.31 0.655 -1.884 -15.466
490 -0.31 -0.655 -0.081 16.398
DEAD LOAD 446 7.957 5.672 -7.646 11.53
490 -7.957 -5.672 -9.371 12.341
SEISMIC +DEAD 446 11.47 7.526 -8.643 40.494
490 -11.47 -7.526 -13.935 -6.084
Beam End Forces in (1-G-H) Frame: H.
Table 10 Beam End Forces in (1-G-H) Frame
Beam L/C Node Shear-Y (KN) Shear-Z (KN) Moment-Y
(KN-m)
Moment-Z
(KN-m)
B993 SEISMIC LOADS 401 -25.561 -0.617 1.154 -51.452
402 25.561 0.617 1.368 -53.094
DEAD LOAD 401 44.827 -0.102 0.185 28.266
402 50.063 0.102 0.234 -38.973
DEAD+SEISMIC 401 105.583 0.771 -1.453 119.577
402 36.752 -0.771 -1.702 21.181
B1111 SEISMIC LOADS 445 -15.652 -0.843 1.571 -31.538
446 15.652 0.843 1.877 -32.477
DEAD LOAD 445 44.956 -0.209 0.372 28.482
446 49.934 0.209 0.482 -38.663
DEAD+SEISMIC 445 90.911 0.951 -1.799 90.03
446 51.424 -0.951 -2.093 -9.28
B1229 SEISMIC LOADS 489 -8.315 -1.009 1.864 -16.134
490 8.315 1.009 2.264 -17.875
DEAD LOAD 489 14.16 -0.482 0.888 7.892
490 18.644 0.482 1.084 -17.062
DEAD+SEISMIC 489 33.712 0.79 -1.463 36.039
490 15.493 -0.79 -1.77 1.219
V. CONCLUSION
The results as obtained using STAAD PRO 2006 for with and without infill walls are compared for different categories
The Bending Moment chart, Table 3of a beams shows a difference between with and without infill walls where without infill walls show the maximum values. The difference in bending moment is Twice of with infill walls
In Table number 4 the storey drift shows a difference between with and without infill walls where without infill walls shows the maximum drift. The difference in storey drift is 50% higher for without infill than with infill walls.
In Table number 5, the Nodal displacement shows a difference between with and without infill walls where without infill walls show the maximum displacement. The difference in nodal displacement is 2 times higher for without infill
than with infill walls
The Shear Force Table number 6 of a beams shows the variations between with and without infill walls where without infill walls will be having maximum amount of shear force than with infill walls
As per the results in Table No 7, We can see that there is not much difference in the values of Axial Forces as obtained by With and Without infill walls of the RCC Structure..
Nodal Displacements and Bending moments in beams and columns due to seismic excitation showed much larger values compared to that due to static loads.
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REFERENCES
[1] B.Srinavas and B.K.Raghu Prasad The Influence of Masonry in RC Multistory Buildings to Near- Fault GroundMotions Journal of International Association for Bridge and Structural Engineering (IABSE) 2009, PP 240-248.
[2] Indian Standard, Criteria for earthquake resistant design of structures, IS 1893(part 1):2002, Bureau of Indian Standards, New Delhi. [3] Indian Standard, Code of practice for plain and Reinforced Concrete,IS 456:2000,Bureau of Indian Standards, New Delhi. [4] Mehmet Metin Kose Parameters affecting the fundamental period of RC buildings with infill walls Engineering Structures 31 (2009), 93-102. [5] V.K.R.Kodur, M.A.Erki and J.H.P.Quenneville Seismic analysis of infilled frames Journal of Structural Engineering Vol.25, No.2, July 1998 PP 95-102.