Abstract

After a catastrophic ground motion, the strength of a damaged steel bridge to resist both its self-weight and traffic loads usually needs to be re-evaluated. This aspect is especially true for bridges located in highway network intersections. However, in the current evaluation process, the strength of the deteriorated material is often underestimated, which may lead to the adoption of an inappropriate decision for the treatment of a damaged bridge. In this work, an accurate hysteretic model incorporating the strength degradation for structural steel is proposed based on experimental results. Furthermore, a case study on the post-earthquake strength of a deck-through type steel arch bridge was performed. The relationship between the prior seismic damage level and the remaining strength was investigated. The results indicate that the decreases in the material strength predicted by the hysteretic model are in good agreement with the experimental results. The stiffness of the bridge is unaffected by the seismic damage. The structure retains more than 90% of its original strength in most cases after the ground motions. However, the ductility of the structure decreases dramatically due to the prior seismic damage. Moreover, the remaining ductility of the damaged bridge decreases linearly with the preceding seismic intensities (PGA).

摘要

在发生灾难性的地面运动之后，通常需要重新评估受损钢桥抵御自重和交通负荷的强度。对于位于高速公路网络交叉口中的桥梁，这一方面尤其如此。但是，在当前的评估过程中，经常会低估退化材料的强度，这可能导致采用不适当的决定来处理受损桥梁。在这项工作中，基于实验结果，提出了一种包含结构钢强度退化的精确滞后模型。此外，还进行了甲板贯通型钢拱桥地震后强度的案例研究。研究了先前地震破坏水平与剩余强度之间的关系。结果表明，由滞回模型预测的材料强度的下降与实验结果吻合良好。桥梁的刚度不受地震破坏的影响。在地面运动后的大多数情况下，该结构可保留其原始强度的90％以上。但是，由于先前的地震破坏，结构的延展性急剧下降。此外，受损桥梁的剩余延展性随先前的地震强度（PGA）线性降低。由于先前的地震破坏，结构的延展性急剧下降。此外，受损桥梁的剩余延展性随先前的地震强度（PGA）线性降低。由于先前的地震破坏，结构的延展性急剧下降。此外，受损桥梁的剩余延展性随先前的地震强度（PGA）线性降低。