A STUDY ON THE CYPRESS VIADUCT COLLAPSE AND SEISMIC PERFORMANCE OF A RETROFITTED BENT

Abstract

This paper describes numerical simulation studies on the bent collapse of the Cypress Viaduct during the Loma Prieta Earthquake and on the seismic performance of the same type bent retrofitted. The purpose of the 1st simulation is to identify bent damage due to ground conditions and structural types and that of the 2nd simulation is to estimate seismic performance of the retrofitted bent. Systematized analyses provided following conclusions: 1) Amplified ground motion was appropriately predicted based on the multiple reflection theory, 2) Finite element nonlinear analyses provided good agreement with test results both of pre-retrofitted and retrofitted bents, 3) Nonlinear dynamic response analyses provided quantitative explanation on the relationship between ground conditions, bent types and bent collapses and also ensured sufficient seismic safety of the retrofitted bent.