Soil liquefaction occurs when saturated soil loses strength and behaves like liquid. First described by Allen Hazen in 1918 Calaveras Dam failure. Most common in loose, saturated sandy soils. Water fills pore spaces between soil grains during compression. Rapid loading can cause water pressures to exceed soil grain contact stresses
PGA is the maximum ground acceleration during earthquake shaking at a location. Measured in three directions: vertical and two horizontal components. Can be expressed in g, m/s², or Gal units
OpenSees is an open-source earthquake engineering simulation framework using finite element methods. Developed by PEER since 1997 with large community support. Available as free, royalty-free software for non-commercial use
Study aims to measure shear wave velocities in Dhaka using PS logging. Seventeen locations selected in Dhaka, ten conducted by author. Most sites located on reclaimed areas with filling sand up to 15-20m
Interactive web application based on DGML 2.0 software. Contains shallow crustal earthquakes in active tectonic regimes. Funded by PEER & NEES Annual Meeting in San Francisco
Critical response formula developed for structures with three uncorrelated seismic components. Higher modes affect maximum building response to horizontal earthquake motion. Design formulas developed for different building sizes and structural systems. Performance-based design shows better cost-effectiveness than prescriptive codes