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原文传递 Effects of Boundary Conditions on Bridge Performance

题名：	Effects of Boundary Conditions on Bridge Performance
作者：	Nur Yazdani, Ph.D., P.E. and Tanya Green
关键词：	Bearing Pads, Bearing Stiffness, Skewness, Bridge Performance
摘要：	Reinforced elastomeric bearing pads generally support precast concrete bridge girders. The condition of these bearing pads and the pad-bridge interface define the support boundary conditions of the bridge superstructure. The interface between bearing pads and bridge girders affect the performance of the superstructure and the substructure. The pads are designed to carry vertical loads, and to accommodate horizontal movements of the bridge girders. The objectives of this study were to determine the effects of various parameters on the bridge superstructure performance and to compare the girder performance with simple support conditions corresponding to the current FOOT design. A parametric study on the interaction of the support boundary conditions and bridge girders was performed in this study. Some of the parameters included; the skewness of the bridge, the presence of intermediate diaphragms, and the temperature effects on the bridge superstructure. A finite element model of a bridge superstructure containing Florida Bulb Tee 78 girders was created using ANSYS software. This model was subjected to an HL93 truck load as pertaining to LRFD AASHTO specifications. The results indicate that pads with higher bearing stiffness are beneficial to bridges with higher skew angles. Intermediate diaphragms have the positive effect of reducing the overall midpoint deflections and maximum stresses for the bridge system. However, the reductions in deflections and stresses are smaller for increasing skew angles.
报告类型：	科技报告