Investigation Of Earthquake Resistance And Cost Effect On Hybrid Cable-stayed Bridge With Two Girders

Abstract

Nowadays hybrid structures composed of concrete and steel are widely constructed in Japan and known to be superior against earthquakes and to be cost effective. In this study, a bridge of 340m in length which crosses a valley was used as a model object, in which the hybrid cable-stayed bridge of two grders was proposed as the most economical bridge, having significant resistance against earthquake. After having carried out investigations from many different aspects, this paper focuses on the subjects as shown below. By imposing bearing support condition on the top of pier (for example. fixed bearing, movable bearing. base isolation bearing) as parameters, dynamic analyses were carried out by using 3-dimensional analytical models that introduce inelastic elements in a RC pier. As a result, the optimum dimension of the R C pier and bearing conditions were determined. T o investigate the effects o n the isolation bearing. parametric analysis on characteristics of the isolation bearing was carried out. In addition to a design for a hybrid cable-stayed bridge with two girders. a PC continuous rigid frame bridge and steel arch bridge were designed to investigate cost effectiveness. By calculating quantities of works, cost comparisons of these bridges was carried out. I t was concluded from these investigations that by using the isolation bearing the proposed bridge was superior in cost effectiveness and earthquake resistance.