VERTICAL COMPONENT EFFECT OF EARTHQUAKE IN SEISMIC PERFORMANCE OF REINFORCED CONCRETE BRIDGE PIERS

摘要

Reinforced Concrete (R.C.) bridges with single piers have been used extensively in Iranian highways similar to the other countries. Sever damage of this kind of piers during past earthquakes in Japan, USA, New Zealand and other countries indicates inadequacy of seismic design and construction requirements. After 1995 Kobe earthquake in Japan and extensive damage of Hanshin highway bridge piers, the vertical component effect of earthquake ground motions is considered as an important parameter for vulnerability of R.C. bridge piers. In this paper, these effects have been studied in a bridge with single piers using nonlinear dynamic analyses. Horizontal and vertical component of the 1978 Tabas earthquake in Iran have been used as input ground motion. Analytical results indicate more than 30 percent increases in axial forces. Changing the ductile bending cracking pattern to brittle shear cracking pattern due to the vertical component effect of earthquake ground motion is another important observation.