International Journal of Science, Engineering and Technology Research (IJSETR) Volume 1, Issue 1, July 2012 Comparative Study of Static and Dynamic Analysis of Irregular Reinforced Concrete Building due to Earthquake Ni Ni Win, Kyaw Lin Htat Abstract— This paper presents comparative study of static and dynamic analysis of irregular reinforced concrete building due to earthquake. In present study, computer aided analysis of twelve-storied reinforced concrete building is carried out for static and dynamic analysis by using ETABS (Extended Three dimensional Analysis of Building System) software. Load consideration is based on Uniformed Building Code (UBC-1997). The structure is designed in accordance with American Concrete Institute (ACI-318-99) design code. Firstly, the proposed building is analyzed with static analysis. Secondly, dynamic analysis with response spectrum method is used. In this paper, the results of static and dynamic (response spectrum) analysis such as displacement, storey shear, storey moment and storey drift are compared. Index Terms— Static analysis, Response spectrum method, Irregular reinforced concrete building, Earthquake. I. INTRODUCTION Nowadays many developed countries have been widely used the irregular buildings in various forms. With the rapid growth of urban population, reinforced concrete building has been used in both the developing and industrialized countries. The extensive use of reinforced concrete construction, especially, in developing countries, is attributed to its relatively low initial cost compared to other materials such as steel. Myanmar is a developing country; so many residential and other public buildings are needed for social, ecological, economical and public demands. Myanmar is situated in seismic belt which is in the junction of two major belt called Alps-Himalaya and Circum Pacific belt. Thus many areas are often subjected to frequent earthquake. The proposed building of this study is located in seismic zone IV. So it is needed to consider the effect of earthquake in designing the buildings. Earthquake consists of random horizontal and vertical movement of the earth’s surface. In this study horizontal component of ground motion is only considered for the dynamic analysis because the structures are usually much stiffer and stronger in response to vertical loads than they are in response to horizontal loads. The main objective of this paper is to study the seismic response of irregular reinforced concrete building. The main goal of earthquake resistance Manuscript received Oct 15, 2011. Ni Ni Win, Department of Civil Engineering, Mandalay Technological University, (e-mail: niniwin965@gamil.com). Mandalay, Myanmar, Mobile No.,+9509400524591 Kyaw Lin Htat, Department of Civil Engineering, Mandalay Technological University, Mandalay, Myanmar, Mobile No.+950943161370 (e-mail: kyawlinhtat@gmail.com). design is to prevent building collapse during earthquake, thus, minimizing the risk of death or injury to people in or around those buildings. Therefore, in this study, the proposed building is designed to withstand the lateral force due to earthquake by using ETABS software. II. PREPARATION A. Site Location and Structural System The superstructure of the proposed building is designed as dual system containing special moment resisting frame (SMRF) based on UBC-1997 and is analyzed with ETABS software. Type of building = Twelve-storied R.C building Type of occupancy = Hotel Shape of the building = Irregular Box-shaped Ground floor height =14 ft Typical height =10 ft Overall height =132ft Maximum length =129 ft Maximum width =99 ft Location =Seismic zone - 4 B. Material Properties Of The Structure Material properties used for the proposed building are as follows: Unit weight of concrete = 150pcf Modulus of elasticity = 3122ksi Poisson’s ratio = 0.2 Strength of concrete (fc ') = 3ksi Yield strength of main reinforcement (fy) = 50ksi Yield strength of shear reinforcement (fys) = 50ksi C. Loading Consideration 1) Dead loads Unit weight of concrete = 150pcf 4½ inches thick wall weight = 50psf 9 inches thick wall weight = 100psf Weight of glass area = 10psf Weight of elevator = 2 tons Weight of ceiling and finishing = 25psf 2) Live loads Live load on lobbing = 100psf Live load on corridors = 100psf Live load on stairs = 100 psf Live load on restaurants = 100 psf Live load on Assembly hall = 100psf Live load on bed room = 40psf Live load on roof = 20psf 3) Earthquake load Seismic zone = IV 1 All Rights Reserved © 2012 IJSETR International Journal of Science, Engineering and Technology Research (IJSETR) Volume 1, Issue 1, July 2012 Structural system = Dual system with SMRF Seismic zone factor = 0.4 Response modification factor, R = 8.5 Seismic importance factor, I = 1.0 Soil profile type = SD Seismic response coefficient, Ca = 0.44 Na Seismic response coefficient, Cv = 0.64 Nv Seismic source type =A Near source factor, Na = 1.0 Near source factor, Nv = 1.0 4) Wind load Exposure type = Type B Basic wind velocity = 80 mph Windward coefficient = 0.8 Leeward coefficient = 0.5 Importance factor = 1.0 Overall height = 132ft D. Load Combinations Design is the process of determining the size and the arrangement of structural members to withstand the various load combinations. According to (ACI-318-99) and UBC-97, the load combinations are used 30 types in this study. These load combinations are shown in Table I. Table I No Load Combination 1 1.4 DL 2 1.4 DL + 1.7 LL 3 1.05 DL + 1.275 LL + 1.275 WX 4 1.05 DL + 1.275 LL – 1.275 WX 5 1.05 DL + 1.275 LL + 1.275 WY 6 1.05 DL + 1.275 LL – 1.275 WY 7 0.9 DL + 1.3 WX 8 0.9 DL – 1.3 WX 9 0.9 DL + 1.3 WY 10 0.9 DL – 1.3 WY 11 1.05 DL + 1.28 LL + EQX 12 1.05 DL + 1.28 LL – EQX 13 1.05 DL + 1.28 LL + EQY 14 1.05 DL + 1.28 LL – EQY 15 0.9 DL + 1.02 EQX 16 0.9 DL – 1.02 EQX 17 0.9 DL + 1.02 EQY 18 0.9 DL – 1.02 EQY 19 1.16 DL + 1.28 LL + EQX 20 1.16 DL + 1.28 LL – EQX 21 1.16 DL + 1.28 LL + EQY 22 1.16 DL + 1.28 LL – EQY 23 0.79 DL + 1.02 EQX 24 0.79 DL – 1.02 EQX 25 0.79 DL + 1.02 EQY 26 0.79 DL – 1.02 EQY 27 1.3305DL +1.275LL +1.4025SPECX 28 1.3305DL +1.275LL +1.4025SPECY 29 0.6140 DL + 1.43 SPECX 30 0.6140 DL + 1.43 SPECY III. DESIGN SECTION OF THE MODEL Plans of twelve storied reinforced concrete building with different floors and three dimensional view are shown in figures. The beam sections used in this model are B10"×12", B10"×14", B10"×16", B10"×18", B12"×14",B12"×18", B12"×24", B14"×16", B14"×18", B14"x20", B14″x22″, B14″x24″, B16″x22″, and B16x24" and the column sections are C12"×12", C14"×14", C16"×16", C18"×18", C20"×20", C22"×22" and C24"×24". The thickness of floor slab is 5". Fig.1. First to Sixth Floor Plan (storey 1 to 6) Fig.2. Seventh to Eighth Floor Plan(storey 7 to 8) Fig.3. Ninth to Twelfth Floor Plan (storey 9 to 12) 2 All Rights Reserved © 2012 IJSETR International Journal of Science, Engineering and Technology Research (IJSETR) Volume 1, Issue 1, July 2012 Fig.6.(a) Maximum Storey Shear of Stories in Static and Response Spectrum method in X-direction Fig.4. Three Dimensional View of the model IV. COMPARATIVE ON DESIGN RESULTS FOR SUPERSTRUCTURE Displacement Comparison is shown in Fig.5.(a) and Fig.5.(b). Storey shear comparison is shown in Fig.6.(a) and Fig.6.(b). Storey moment comparison is shown in Fig.7.(a) and Fig.7.(b). Storey drift comparison is shown in Fig.8.(a) and Fig.8.(b). Fig.6.(b) Maximum Storey Shear of Stories in Static and Response Spectrum method in Y-direction Fig.7.(a) Maximum Storey Moment of Stories in Static and Response Spectrum method in X-direction Fig.5. (a) Maximum Displacement of Stories in Static and Response Spectrum method in X-direction Fig.7.(b) Maximum Storey Moment of Stories in Static and Response Spectrum method in Y-direction Fig.5.(b).Maximum Displacement of Stories in Static and Response Spectrum method in Y-direction 3 All Rights Reserved © 2012 IJSETR International Journal of Science, Engineering and Technology Research (IJSETR) Volume 1, Issue 1, July 2012 [1] [2] [3] [4] [5] [6] Nyi Hla Nge, U.: Reinforced Concrete Design, 1st Ed., Pioneer Group, Yangon, (2010). American Concrete Institute: Building Code Requirement for Structural Concrete (318-99) and Commentary (318 R.99), Farmington Hills, M 1, (1999). A.H.Nilson: Design of Concrete Structure. 12th Edition, McGrawHill, Inc. (1997). Uniform Building Code: Structural Engineering Design Provision. Volume 2, (1997). Bryan Stafford Smith and Alex Coull, 1991. Tall Building Structure: Analysis and Design, John Wiley & Sons, Inc. Lindeburg, M. R, and Baradar, M.: Seismic Design of Building Structures: A Professional’s Introduction to Earthquake Forces and Design Details, 8th Ed., Professional Publications, Inc, (2001). Fig.8. (a) Maximum Storey Drift of Stories in Static and Response Spectrum method in X-direction Fig.8.(b) Maximum Storey Drift of Stories in Static and Response Spectrum method in Y-direction V. CONCLUSION In this paper, displacement, storey shear, storey moment and storey drift for both static and dynamic (response spectrum) analysis in X and Y-direction are compared. In X-direction, displacements obtained static analysis are less than dynamic (response spectrum) analysis from storey 1 to 4 and are higher than in response spectrum from storey 5 to 12. In Y-direction, displacements obtained static analysis are less than dynamic (response spectrum) analysis. In both directions, storey shear in static analysis is less than that in response spectrum analysis. The difference of storey moment between static and response spectrum analysis is higher in X-direction and in Y-direction, this difference is lower. In both directions, the difference of storey drift is insignificant. For irregular high-rise buildings, static analysis is insufficient and it is necessary to use dynamic analysis. ACKNOWLEDGMENT The author is highly grateful to her supervisor, Dr. Kyaw Lin Htat, Associate Professor of Civil Engineering Department, Mandalay Technological University, for his patient suggestions, guidance, valuable assistance, supervision and editing this paper. Finally, the author feels very grateful to all her teachers and her family, especially, to her parents for their support and encouragement to attain her destination without any trouble. REFERENCES 4 All Rights Reserved © 2012 IJSETR