Faculty Publications
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Item Non-linear Soil-Structure Interaction Analysis of Multi-storey Shear Wall Buildings with Site Specific Ground Response(Springer Science and Business Media B.V., 2018) Jayalekshmi, B.R.; Chinmayi, H.K.Influence of local geology and soil conditions play a major role in varying the intensity of ground shaking. In the present study, by utilizing the geotechnical data of a specific site, amplification of earthquake motion is found out by ground response analysis. Seismic structural response variation in multistory shear wall buildings with different shear wall locations is determined from nonlinear soil-structure interaction (SSI) analysis using the ground motion with the highest peak ground acceleration obtained from the site. Geotechnical data from twenty bore holes at the site with depth varying between 7–15 m below ground level are considered. This specific site is very near to the Arabian Sea coast with a lot of variation in the geotechnical profile. Symmetric plan multi-storey reinforced concrete shear wall buildings of aspect ratio (h/d) ranging from 1 to 4 resting on raft foundation with shear walls placed symmetrically along the exterior frames, core and all four corners of the exterior frames are considered. Further, the structural responses obtained from SSI analysis and conventional method of assuming rigidity at the base of a structure is compared. Results show the significance of positioning of shear wall in symmetric buildings which attracts the least earthquake forces, with the consideration of nonlinear behavior of the underlying soil medium. © 2018, Springer International Publishing AG.Item Seismic behavior of rc framed shear wall buildings as per is 1893 and IBC provisions(Techno-Press, 2015) Jayalekshmi, B.R.; Chinmayi, H.K.Usually the analyses of structures are carried out by assuming the base of structures to be fixed. However, the soil beneath foundation alters the earthquake loading and varies the response of structure. Hence, it is not realistic to analyze structures by considering it to be fixed. The importance of soil-structure interaction was realized from the past failures of massive structures by neglecting the effect of soil in seismic analysis. The analysis of massive structures requires soil flexibility to be considered to avoid failure and ensure safety. Present study, considers the seismic behavior of multi-storey reinforced concrete narrow and wide buildings of various heights with and without shear wall supported on raft foundation incorporating the effect of soil flexibility. Analysis of the three dimensional models of six different shear wall positions founded on four different soils has been carried out using finite element software LS DYNA. The study investigates the differences in spectral acceleration coefficient (Sa/g), base shear and storey shear obtained following the seismic provisions of Indian standard code IS: 1893 (2002) (IS) and International building code IBC: 2012 (IBC). The base shear values obtained as per IBC provisions are higher than IS values. © 2015 Techno-Press, Ltd.Item Soil–Structure Interaction Effect on Seismic Force Evaluation of RC Framed Buildings with Various Shapes of Shear Wall: As Per IS 1893 and IBC(Springer India sanjiv.goswami@springer.co.in, 2015) Jayalekshmi, B.R.; Chinmayi, H.K.Behaviour of a structure is altered by the interaction amid the structure, foundation and the soil medium below the foundation. This mutual dependent behaviour of structure and soil is called as soil–structure interaction (SSI). Hence, it is not realistic to analyse a structure as per conventional structural design practice which considers the base to be fixed. Comparative study on seismic provisions of Indian seismic code, IS 1893:2002 (IS) and International building code IBC:2006 (IBC) is carried out in present study to look into the effect of soil flexibility on variation in natural period, spectral acceleration coefficient, base shear and storey shear. Multi-storey reinforced concrete framed buildings of varying height with various shapes of shear walls over raft foundation were considered. Analysis of 3D SSI models with three different shear wall shapes founded on four different soil types which are classified based on shear wave velocity has been carried out using finite element software LS DYNA. Study shows the significant effects of SSI in altering the seismic response of structure. It also shows that the base shear obtained as per IBC are higher than the IS values and the corrugated shape of shear wall experience the lowest base shear compared to cylindrical and rectangular shape shear walls for buildings with aspect ratio below 3. © 2014, Indian Geotechnical Society.Item Seismic force evaluation of RC shear wall buildings as per international codes(Techno Press technop2@chollian.net, 2016) Jayalekshmi, B.R.; Chinmayi, H.K.Seismic codes are the best available guidance on how structures should be designed and constructed to ensure adequate resistance to seismic forces during earthquakes. Seismic provisions of Indian standard code, International building code and European code are applied for buildings with ordinary moment resisting frames and reinforced shear walls at various locations considering the effect of site soil conditions. The study investigates the differences in spectral acceleration coefficient (Sa/g), base shear and storey shear obtained following the seismic provisions in different codes in the analysis of these buildings. Study shows that the provision of shear walls at core in low rise buildings and at all the four corners in high rise buildings gives the least value of base shear. © 2016 Techno-Press, Ltd.Item Dynamic soil-structure interaction analysis of RC framed building with various positions of shear walls(CAFET INNOVA Technical Society 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2016) Chinmayi, H.K.; Jayalekshmi, B.R.In the present study, a three-dimensional dynamic soil-structure interaction analysis of symmetric buildings in time domain is performed using IS spectrum ground motion record corresponding to zone III to evaluate the dynamic response of structure-foundation-soil system. Three types of shear wall buildings of aspect ratio 1, 1.5, 2, 3 and 4 categorized based on the shear wall locations were considered in conjunction with four types of soil of shear wave velocities ranging from 150m/s to 1200 m/s, symbolizing soil classes B, C, D and E of FEMA-356: 2000. Integrated structure-foundation-soil systems were analyzed using commercial finite element software LSDYNA, based on direct method of soil-structure interaction (SSI) assuming linear elastic behavior. The study shows considerable variation in dynamic characteristics and structural seismic response of the structure due to the incorporation of the effect of flexibility of soil and position of shear walls. Tall buildings with shear walls placed at the exterior corners experience the least base shear. © 2016 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Seismic analysis of shear wall buildings incorporating site specific ground response(Techno-Press, 2016) Jayalekshmi, B.R.; Chinmayi, H.K.During earthquake, the motion of ground is affected significantly by source characteristics, source-to-site path properties and local site conditions. Due to the influence of local soil conditions different places experience distinctive amplitude of surface ground motion. Ground response analysis of a specific site utilizing the borehole information at different locations is done in present study. The ground motion with the highest peak ground acceleration for this site obtained from the ground response analysis is used in finite element soil-structure interaction analysis of multi-storey shear wall buildings with various positions of shear walls. The variation in seismic response of buildings and advantageous position of shear wall are determined. The study reveals that providing shear wall at the core of buildings at the specific site is advantageous among all shear wall configurations considered. © © 2016 Techno-Press, Ltd.Item Effect of soil stiffness on seismic response of reinforced concrete buildings with shear walls(Springer, 2016) Jayalekshmi, B.R.; Chinmayi, H.K.Buildings are subjected to lateral loads caused by wind, blasting and earthquakes. The high stresses developed by these loads literally tear the building components apart, which are in general designed for gravity loads. To resist these lateral forces, shear walls can be introduced in buildings. Present study aims to determine the apt shear wall position which attracts the least earthquake forces in symmetric plan multi-storey buildings. Dynamic response of a structure is significantly influenced by the underlying soil due to its natural ability to deform. Three dimensional finite element soil–structure interaction analyses of reinforced concrete shear wall buildings with shear walls placed at various locations is carried out in time domain using scaled down Elcentro ground motion to determine the seismic response variation in the structure due to the effect of stiffness of soil. Four different soil types based on shear wave velocity and six varying shear wall positions in multi-storey buildings up to 16 storeys are considered to determine the effect of soil–structure interaction. From the study, it is found that structural response as per conventional fixed base condition is very conservative. For buildings founded on soil with Vs ? 300 m/s, providing the shear walls at the core is advantageous whereas for soil with Vs > 300 m/s, the shear walls placed at exterior corners of the building attracts the least earthquake force. © 2016, Springer International Publishing Switzerland.