Faculty Publications

Now showing 1 - 3 of 3

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.
Effect of Coir Reinforced Soil on the Seismic Response of RC Framed Buildings
(Springer, 2022) Sreya, M.V.; Jayalekshmi, B.R.; Venkataramana, K.
This study examines the effectiveness of reinforcing the soil with coir mat, a natural material, to act as a seismic soil-isolation medium. A 3D finite element simulation has been carried out on models of five-storey buildings resting on raft foundations in soft and stiff soil with and without the soil-isolation mechanism. The optimum values of the parameters such as the depth of embedment, width, and thickness of the coir mat have been analyzed. The isolated soil-structure system was exposed to two different earthquake motions, such as El Centro (1940) and simulated seismic excitation corresponds to the elastic design spectrum for Zone III as per the Indian Standard code (IS 1893 (Part 1): 2016). The optimum value for the depth of embedment, width, and thickness of the coir mat was identified as B/18, B/0.45 and B/36. The proposed study also deals with the coir (C) mat composited with other isolation materials such as polyethylene (PE) foam, rubber (RU) mat and geomembrane (G) to form C-PE, C-RU and C-G mats. These composites were proposed to increase the durability of the coir mat. The reinforcement of the C-PE mat shows a maximum of about 30% reduction in roof acceleration and 68% reduction in contact pressure. A pore water pressure analysis of soil bed also has been carried out to study the efficacy of these materials to reduce the excess pore water pressure generated in soil under earthquake loading. For that, a simple soft soil is modelled in Cyclic 1D software with and without the soil-isolation mechanism. The soil bed was exposed to El Centro (1940) and Northridge (1994) input motions. C-PE mat significantly reduces the excess pore water pressure by almost 93% and 88% in soil under El Centro and Northridge input motions, respectively. © 2022, Indian Geotechnical Society.
Integrating soil-nailed walls with RC building for seismic stability in space-constrained sites
(Springer Science and Business Media Deutschland GmbH, 2024) Amrita; Jayalekshmi, B.R.; Shivashankar, R.
In urban environments, space constraints necessitate innovative construction methods. Due to rising demand for infrastructures and scarcity of plane ground, structures are built on sloping or irregular ground. To make use of available land, vertical cuts or excavations are made in the natural soil stratum which can be effectively retained using the soil nailing technique. However, if the area adjacent to the nailed vertical cut is utilised for constructing a multi-storeyed building, the behaviour of the nailed structure may vary. This study examines the impact of the presence of multi-storeyed RC buildings on the response of soil-nailed structures in their proximity during earthquake ground motion. The seismic response of a soil-nailed structure is evaluated in the presence of various heights of medium-rise multi-storeyed buildings. Three-dimensional multi-storeyed buildings and soil-nailed structures are analysed with various arrangements and connectivities between them, taking into account different soil profiles at the site. Dynamic finite element analyses of integrated soil-nailed wall-building systems have been performed using time history data of ground motion. The findings suggest that the integration between the two structures enhances the seismic stability of both the structures under dynamic load as evident in the reduced deformation and acceleration of the structures. It restricts the lateral movement of the nailed wall and reduces its displacement by about 40%. This integration can be implemented in space-constrained sites for optimum utilisation of available space. © The Author(s) 2024.

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