OasisLMS

Kolkata, the oldest and capital city of West Bengal situated on the eastern bank of the river Hooghly, is one of the most densely populated regions in the world. Kolkata has suffered major seismic hazards in the past, resulting in severe damages and fatalities. At present, important structures like bridges, flyovers and high rise buildings are being constructed everywhere, mostly supported by pile foundations. In several occasion construction activities may encounter difficult soil deposit resulting either abandoning the site or adopting ground improvement technique to prepare the site suitable for construction activities. In view of recent scarcity of land avoiding a particular construction site with poor soil deposit may not be a viable option. Hence, ground improvement has become an important remedial solution in the field of geotechnical engineering. In the present study, force based pseudo static approach has been utilized to study the lateral response of pile under combined axial and lateral load, embedded in virgin as well as improved clayey deposit, subjected to seismic motion. Beams on Nonlinear Winkler Foundation (BNWF) has been used and nonlinear behavior of soil has been incorporated by using cyclic p-y relationship. Degradation of soil modulus has been obtained from the magnitude of earthquake. MATLAB code has been developed based on FEM to study the lateral pile behavior under earthquake loading. Input accelerogram for Kolkata has been generated considering earthquake source and site parameters. An effort has also been made to get a preliminary estimate of the optimum depth of ground improvement required to achieve maximum lateral pile capacity for pile under seismic motion.

Tanumaya Mitra, ITD Cementation India Limited; Ambarish Ghosh, IIEST, Shibpur; Kalyan Kumar Chattopadhya, IIEST, Shibpur

International Conference Proceedings