International Journal of Advance Engineering and Research Development. Seismic Study of An E-Shaped building With and Without Infill Walls

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1 Scientific Journal of Impact Factor (SJIF): 4.72 International Journal of Advance Engineering and Research Development Volume 4, Issue 5, May-2017 e-issn (O): p-issn (P): Seismic Study of An E-Shaped building With and Without Walls 1 Devipriya. J, 2 Hariprasad T R 1 M Tech Student, Sree Narayana Institute of Technology, Theppupara, Adoor, Kerala 2 Assistant Professor, Department of Civil Engineering, Sree Narayana Institute of Technology Theppupara, Adoor, Kerala Abstract The paper deals with a seismic study on an irregular G+9 building with and without infill walls and its effect on overall seismic response of this building. The presence infill wall has a significant impact on the seismic response of a reinforced concrete frame building, increasing structural strength and stiffness. An irregular E-shaped building is considered for the analysis. This study is to compare various parameters such as storey drift, storey shear, storey displacement, and time period of the building under seismic loads. Different infill materials like brick, AAC block and GFRG panels are used for the analysis. The results obtained were compared to find the suitable infill material for the RC frames. Analysis is done by response spectrum analysis using ETABS. Keywords Irregular building,infill walll, Response Spectrum Analysis. I. INTRODUCTION Earthquakes are natural hazards under which disasters are mainly caused by damage or collapse of buildings and other man-made structures. Building design must be such as to ensure that the building has adequate strength, high ductility, and will remain as one unit, even while subjected to very large deformation. Reinforced concrete frames filled with infill materials are a common practice in countries like India. During building construction, the frame structures are constructed first due to ease of construction and later the frames are infilled by infill materials like masonry brick infill or concrete blocks or finished stones or gypsum panels. The infill walls give protection from outside environment and divide the inside structure like partition walls. It subdivides the internal spaces within the building. s in RC frames reduce the lateral deflection of the building during earthquakes. The infill walls are usually treated as nonstructural element in structural analysis and only its mass contribution is considered and its structural parameters like strength and stiffness is generally ignored. The performance of such structures during earthquakes has proved to be superior to bare frames. When columns receive horizontal forces at floor levels, they try to move in the horizontal direction, but masonry walls tend to resist this movement. Due to their heavy weight and thickness, these walls attract rather large horizontal forces. However, these walls develop cracks once their ability to carry horizontal load is exceeded. Thus, infill walls act like sacrificial fuses in buildings; they develop cracks under severe ground shaking but help to share the load of the beams and columns until cracking. In seismic areas, the frame infill panel interaction cannot be ignored because under a lateral load, an infill in an infilled frame structure separates from the frame near the leeward side (unloaded corner) at top and at the bottom corner near the loaded side. The infill then behaves as a compressive diagonal strut increasing the lateral stiffness of the infill-frame composite structure, thus, contributing to the overall strength and stiffness of the structure. Today in this 21 st century, construction industry is one among which produce greater amount of pollution and wastes which are harmful to our environment. So the use of ecofriendly and recyclable, cost-effective materials is necessary. This leads the researches to new building materials like AAC and GFRG panels which are ecofriendly, reusable cost effective and less time consuming. One of the major advantages of AAC over other cementacious construction materials is its lower impact on environment. It has less efflorescence emission and high thermal insulation. It is easy and quick to install. Glass fiber reinforced Gypsum (GFRG) panel is a new building panel product, where there is a tremendous need for cost-effective mass-scale affordable housing. GFRG panel otherwise called Rapid wall, is a vitality effective green building material with gigantic potential for use as load bearing and non-load bearing wall panels. II. OBJECTIVES To study the seismic behavior of reinforced concrete framed building with infill walls. To study the effect of parameters like storey displacement, storey drift and storey shear for the models considered in this study. To compare the results using infill materials like brick, AAC blocks and GFRG All rights Reserved 222

2 III. SCOPE The study focuses on the effect of infill walls on the seismic behavior of an irregular E shaped building. Openings in infill walls are not considered in the analysis. IV. ANALYSIS OF MODELS The G+9 (10 story) E-shaped building is analyzed by response spectrum method for zone IV for models with and without infill materials. The seismic analysis is carried out by ETABS. Details of the model for analysis are shown in table 1. M 20 Grade concrete and Fe 415 steel are used. TABLE 1.Details of Model Beam size 300 x 450 mm Column size 450 x 450 mm Story height 3m for all floors Thickness of masonry wall 230mm Thickness of slab 150mm No: of bays in X direction 4 No: of bays in Y direction 5 Bay width in X and Y 5m directions Floor finish 1kN/m 2 Roof finish 1kN/m 2 Live load on roof 1.5kN/m 2 Live load on floor 2.5kN/m 2 Seismic zone IV Zone factor, Z 0.24 Response reduction factor, R 5 Importance factor, I 1 A. Models For Analysis Four models were considered for the analysis. Model 1 is building without infill wall (fig 1).Other models have different infill materials like brick, AAC block and GFRG panels (fig.2).the models were analysed by response spectrum analysis using ETABS. From this analysis storey displacement, storey shear, storey drift and time period of different models were obtained. The results can be compared and graphed. The models for analysis are: Model 1: Building without infill Model 2: Building with brick infill Model 3: Building with AAC infill Model 4: Building with GFRG infill Properties of RC frame and the infill materials used for the analysis are Thickness of infill wall: 230 mm Density of concrete: 25 kn/m 3 Density of brick infill: 18 kn/m 3 Density of AAC block infill : 7 kn/m 3 Density of GFRG : 11 kn/m 3 Poisson s Ratio of concrete : 0.2 Poisson s Ratio of brick masonry : 0.16 Poisson s Ratio of AAC masonry : 0.25 Poisson s Ratio of GFRG :0.2 Modulus of Elasticity of concrete:25 kn/mm 2 Modulus of Elasticity of brick masonry:3 kn/mm 2 Modulus of Elasticity of AAC: 3.5 kn/mm 2 Modulus of Elasticity of GFRG : 7.5 kn/mm All rights Reserved 223

3 Fig.1. Building model without Fig.2.Building model With In the modelling of building with infill, materials are changed in each case. The materials used for infill materials are brick, AAC block abd GFRG panels. V. RESULTS AND DISCUSSION Based on the results obtained, comparison was made for storey displacement, storey drift, storey shear and time period by response spectrum analysis considering the models with and without infills. The tables and graphs are shown All rights Reserved 224

4 TABLE 2.Storey Displacement for models by Response Spectrum Analysis (mm) Storey Displacement(mm) Storey No: Without Brick AAC GFRG Base Storey Storey Storey Storey Storey Storey Storey Storey Storey Storey The graph (fig.3.) below shows the storey displacement at different storey levels. The model without infill has maximum storey displacement than other models. GFRG infilled model has minimum storey displacement than all other models. Fig.3. Story Displacement As per IS1893 (Part 1):2002, the permissible limit for the storey displacement is H/500.where H is the total storey height. i.e /500 =60 mm. Therefore obtained results are within the permissible All rights Reserved 225

5 TABLE 3.Storey Drift for Building by Response Spectrum Analysis Storey Storey Drift No: Without Brick AAC GFRG Base Storey Storey Storey Storey Storey Storey Storey Storey Storey Storey The graph (fig.4.) below shows the storey drift at different storey levels. The model without infill wall has maximum storey drift than other models. Model with GFRG infill has minimum storey drift than all other models. Fig.4. Story Drift As per IS1893 (Part 1):2002, the permissible limit for the storey drift is 0.004h.where h is the storey height. i.e x 3000 =12 mm. Therefore obtained results are within the permissible All rights Reserved 226

6 TABLE 4. Storey Shear For Building By Response Spectrum Analysis (kn) Storey Storey Shear (kn) No: Without Brick AAC GFRG Base Storey Storey Storey Storey Storey Storey Storey Storey Storey Storey The graph (fig.5.) below shows the storey shear at different storey levels. The model without infill wall has minimum storey shear than other models. AAC and GFRG infill has approximately equal storey shear values. Fig.5. Story Shear Base shear of models with AAC blocks and GFRG panels was significantly smaller than that with conventional clay bricks. Model without infill experiences very less base shear than with infill All rights Reserved 227

7 Mode No: TABLE 5.Time Period for the Building Without Time Period (sec) Brick AAC infill GFRG infill The graph (fig.6.) below shows the time period for different modes. The model without infill wall larger time period than other models. AAC and GFRG infill has approximately equal time period values. Fig.6. Time Period VI. CONCLUSIONS The model without infill wall experiences high storey displacement, storey drift and larger time period than the models with infill wall. Model with GFRG panel has comparatively less storey displacement, storey drift and time period. Base shear of models with AAC blocks and GFRG panels was significantly smaller than that with conventional clay bricks, which results in reduction in member forces which leads to reduction in required amount of area of steel to resist member forces. GFRG panels are green building material and they are easy to install and cost of construction is low. So it can be taken as best infill material The storey displacement and storey drifts are within the permissible All rights Reserved 228

8 This work can be performed using other infill materials. Results can be compared with time history analysis. Results can be compared using other software. FUTURE SCOPE ACKNOWLEDGMENT The authors(s) wish to express their gratitude to Dr.P.G.BHASKARAN NAIR, P.G.Dean. Sree Narayana Institute of Technology, Adoor for his valuable suggestions, encouragement and motivation. Above the author thank GOD Almighty for his grace throughout the work. REFERENCES [1] Narendra A. Kaple, S.D.Malkhede, Seismic Analysis Of RC Frame Structure With And Without Masonry Walls, International Conference on Electrical, Electronics, and Optimization Techniques (ICEEOT) 2016 [2] Lini M Thomas, Kavitha P.E., Effect of Walls on the Seismic Performance of the Multistoried Buildings, IJRET: International Journal of Research in Engineering and Technology eissn: ,pISSN: , October 2015 [3] Mohammed Rizwan Sultan, D. Gouse Peer, Dynamic analysis of multi-storey building for different shapes International Journal of Innovative Research in Advanced Engineering, August 2015 [4] Prof. N Murali Krishna, Md Masihuddin Siddiqui Non Linear Time History Analysis of Building with Seismic Control Systems IJSTE - International Journal of Science Technology & Engineering, February [5] Hrushikesh, Prof. Lokesh, Study on Effect of Walls in Multistorey Irregular R.C. Framed Structure with Shear Wall, International Journal for Scientific Research & Development,2015 [6] Mr. Gururaj B.Katti, Dr. Basavraj S. Balapgol Seismic Analysis of Muiltistoried RCC Buildings Due to Mass Irregularity By time history analysis, International Research Journal of Engineering and Technology (IRJET,July [7] Mohammed Nauman, Nazrul Islam, Behaviour of RCC Multistorey Structure With and Without Walls, International Journal of Innovative Research in Science, Engineering and Technology ISSN: , January 2014 [8] Vikas P. Jadhao, Prakash S. Pajgade, Influence of Masonry Walls on Seismic Performance of RC Framed Structures a Comparison of AAC and Conventional Brick, International Journal of Engineering and Advanced Technology (IJEAT) ISSN: ,Volume-2, Issue-4, April 2013 [9] Bahador Bagheri, Ehsan Salimi Firoozabad, Mohammadreza Yahyaei, Comparative Study of the Static and Dynamic Analysis of Multi-Storey Irregular Building, International Journal of Civil, Environmental, Structural, Construction and Architectural Engineering, May 2012 [10] IS 1893 (Part 1): (2002), Criteria for Earthquake Resistant Design of Structures, Bureau of Indian Standards, New Delhi [11] IS 456 : 2000, Plain and reinforced concrete-code of practice,bureauof Indian standards, New Delhi.. [12] IS-875 (Part-1)-1987 code of practice for design loads (other than earthquake loads) for buildings and structures: part-1 for dead loads [13] IS-875 (Part-2)-1987 code of practice for design loads (other than earthquake loads) for buildings and structures: part-2 for imposed loads [14] IS-875 (Part-3)-1987 code of practice for design loads (other than earthquake loads) for buildings and structures: part-2 for wind All rights Reserved 229