INELASTIC MODELING AND PERFORMANCE BASED ANALYSIS OF A BRIDGE BENT

Abstract

Bridges are an essential link in the transportation lifeline system and they are required to remain in service during and after the occurrence of an earthquake. Bridges give the impression of being a simple structure, but despite their structural simplicity, bridges have not performed as well as might be expected under seismic attack. The most serious bridge damage occurs when a bridge deck falls off of its support, or from column failure due to excessive shear or flexural demands from earthquake motions. During recent earthquakes in California (USA) and Japan, the most common failure in most of the bridges was column failure exhibiting large inelastic deformation at the base during earthquake loading. Therefore, a need for inelastic modeling of a column base and associated concept of ductility arises for survival of bridge during severe seismic response. This investigation was carried out to know a how a bridge column behaves during an earthquake when it is modeled to sustain inelastic deformation. The deformation and damage behavior of a reinforced concrete bridge subjected to push-over and dynamic loads is studied through nonlinear static and dynamic analysis. A circular bridge column was modeled using inelastic component (plastic hinge) at the base. Different performance levels were defined to check that the structure was not damaged beyond the acceptable limits of the performance objective.