可复位桥梁外剪力键性能试验及承载能力评估

在桥梁抗震设计中，剪力键既要限制上部结构横向位移过大以防止发生落梁，又要避免传递过大的横向地震力造成桩基础的损伤，因此通常被设计成牺牲型单元。该文基于一种新型可复位桥梁外剪力键，并结合我国桥梁工程实际，对约束良好的4个新型可复位桥梁外剪力键试件进行单向水平荷载试验，阐明了该新型可复位外剪力键的破坏形态、失效模式和受力机制，分析竖向配筋率对该类新型外剪力键力学特性的影响，建立新型剪力键的承载能力计算公式，且计算结果与试验数据吻合较好。研究结果表明:该类新型剪力键能够有效地减小桥墩盖梁或桥台台帽损伤，且具有位移能力强、易修易换等优点，尤其适用于基于性能的桥梁抗震设计。

BEHAVIOR EXPERIMENT AND CAPACITY EVALUATION OF RESILIENT EXTERIOR SHEAR KEY OF BRIDGES

In the aseismic design of bridges, shear keys should not only restrict the superstructure transverse displacement to prevent from unseating, but also void transferring the excessive seismic force to piles. Therefore, shear keys are commonly designed as sacrifice members. Based on a kind of novel resilient bridge exterior shear keys, four shear key specimens were designed in accordance with current Chinese aseismic design guidelines of highway bridges and tested under monotonic transverse loading. The damage modes, failure models and mechanical mechanisms were illustrated. Parametric study was carried out on a longitudinal reinforcement ratio. Calculation formulas were developed to predict the capacities of shear key specimens. Compared with the experimental results, the calculation formulas can reliably evaluate the capacities of shear key specimens. It can be concluded that this kind of resilient exterior shear keys have excellent displacement capacity, and can reduce the damage to cap beams and abutments. In addition, they are easy to be repaired and replaced, and especially suitable for performance-based aseismic design of bridges.