SOIL-BASEMENT STRUCTURE INTERACTION ANALYSIS ON DYNAMIC LATERAL EARTH PRESSURE ON BASEMENT WALL
Dynamic soil-basement structure interaction using time-domain approach to recommend dynamic lateral earth pressure on basement wall is presented. The analyses consider various parameters involved in the soil-basement structure system. These parameters are soil condition or site-class, peak base acceleration, frequency content of input motion, depth of basement, depth of base-rock, and stiffness of the basement structure. The variations in soil condition are homogenous clay deposit with reference to IBC2006 site classification SC, SD and SE for hard soil, medium-stiff, and soft class, respectively. The study focused on identifying sensitivity of these parameters on dynamic response of the soil-basement structure system. The dynamic soil-structure interaction analyses were conducted using dynamic finite element software, adopting non-linear elasto-plastic Mohr-Coulomb soil model with Rayleigh damping. Result of the analyses indicated that distribution of the dynamic lateral earth pressure reach its maximum value on the basement wall with almost linear pressure increments with depth on soft soil and non-linear pressure increments on medium-stiff and stiff soil. The highest pressure increment is identified to occur near bottom of the basement wall. The sensitivity analysis on the peak base acceleration results in higher maximum lateral earth pressure with higher peak base acceleration with some variation depending upon the site-class. The maximum lateral earth pressure and its point of application are increasing proportionally with depth of basement wall. Recommendation of seismic lateral pressure distribution considering the site-class and peak base acceleration is provided.