Earthquake Engineering: New Research

Abstract

This new book deals with earthquake engineering including seismology, tsunamis, ground motion characteristics, soil and foundation dynamics, wave propagation, probabilistic and deterministic methods of dynamic analysis, experimental behaviour of structures, and methods for earthquake resistant design and retrofit of structures that are germane to practicing engineers. It includes seismic code requirements and system identification, as well as supplemental energy dissipation, base isolation, and structural control emphasizing earthquake engineering. While full three-dimensional (3D) numerical simulation is a solution to estimate strong ground motion and a seismic structure response for a given earthquake, it is difficult to carry out numerical computation because of its huge computational cost; the order of a target domain size is 104~5m and the target resolution required is 10−2~0m. In Chapter 1, we present an efficient approach which is based upon multi-scale analysis to make a 3D simulation of wave propagation and amplification as well as seismic responses of an infrastructure. The formulation of themulti-scale analysis is presented, and it is validated by comparing a strong ground motion and a seismic structure response which is obtained by directly analyzing the whole system. The usefulness and applicability of this multiscale approach are also discussed. Newmark's sliding-block model is usually employed to predict the seismic displacement of slopes. Yet, when displacement is large, the conventional sliding-block model predicts displacements that are larger than expected for the given input motion and soil strength. Alternatively, to simulate slope movement when the displacement is large, a multi-block sliding model has been proposed. Similarly to the Sarma (1979) stability method, a general mass sliding on a slip surface that consists of n linear segments is considered. In order for the mass to move, interfaces where resisting forces are exerted must be formed between nodes of the slip surface. Thus, the mass is divided into n blocks sliding in n different inclinations. For landslides, the masses and lengths of each block entering the calculation are updated in terms of the distance moved. In addition, constitutive equations that simulate strength degradation along the slip surface coupled with the multi-block model are proposed in order to simulate the triggering of the slides. On the other hand, gravity walls, as a result of the applied shaking, move outwards, away from the retained soil. Simplified analyses predicting the seismic displacement of gravity walls are based on the Mononobe-Okabe method combined with Newmark's sliding-block model. The wall-backfill system is modeled, according to the