A Novel Geomechanics Concept for Earthquake Excitations Applied in Time Domain

A novel geomechanics concept is presented for studying the behavior of geomaterials and structures by capturing the underlying dynamics as realistically as possible for earthquake excitation applied in time domain. Enormous amount of damages caused to infrastructures during recent earthquakes in all over the world indicate that there is a considerable room for improvement. Causes for extensive damages are generally attributed to poor soil conditions at the region. It is interesting to note that all structures in a region with poor soil condition do not suffer similar damages; in fact, some of them remain damage-free. There are many reasons for this including inability to model the soil-structural systems properly, predict the future design earthquake time history at the site, model the dynamic amplification of responses caused by the excitation, incorporate major sources of nonlinearity and energy dissipation, and most importantly consider the presence of a considerable amount of uncertainty at every phase of the evaluation process. The most recent research trend is to capture complicated behavior by conducting multiple deterministic analyses by taking advantage of current significantly improved computational capability. By conducting few dozens of deterministic analyses at very intelligently selected points, structures can be designed more seismic load-tolerant. The performance based seismic design concept recently introduced in the U.S. is showcased in this paper. The requirements in the guidelines appear to be reasonable. The concept is expected to change the current engineering design paradigm. The authors believe that the proposed alternatives to the simulation and the basic random vibration concept.