中文摘要：

为使中小跨度梁桥中混凝土挡块的性能得以充分发挥,针对汶川地震中小跨度梁桥的典型震害特征,建立板式橡胶支座滑动以及混凝土挡块力学性能的简化计算模型,以3×30m一联的连续梁桥为例,采用OpenSees建模分析混凝土挡块对结构横向抗震性能的影响及其设计参数（强度、变形能力）的合理取值。结果表明：对于中小跨度梁桥,混凝土挡块强度取桥墩横向屈服力的0.45倍左右、变形能力取板式支座临界滑动位移的1.5-2.0倍较为合理;在不同地震动强度和不同墩高的情况下,混凝土挡块按照合理参数取值可有效控制支座的最大位移需求、降低结构发生横向落梁的风险,同时下部桥墩的地震损伤也可以维持在容许范围内。

英文摘要：

To bring the performance of the concrete shear keys for the short and medium span beam bridges into full play ,the simplified calculation models for the sliding of the laminated rub‐ber bearings and the mechanical performance of the concrete shear keys were built up with refer‐ence to the typical seismic damage of the short and medium span beam bridges in the Wenchuan earthquake .By way of example of a continuous beam bridge with each continuous unit of 3 × 30-m spans ,the Opensees was used to create the model and the influences of the shear keys on the trans‐verse seismic performance of the structures and the selection of the proper design parameter values （e .g .the strength and deformation capacity） for the shear keys were analyzed .The results of the analysis demonstrate that for the short and medium span beam bridges ,it will be proper if the val‐ues of about 0 .45 times of the transverse yielding forces of the piers are selected for the strength and the values of 1 .5-2 .0 times of the critical sliding displacement of the laminated rubber bear‐ings are selected for the deformation capacity of the shear keys .Under the situations of the differ‐ent intensity of the ground motion and the different pier height ,the selection of the proper design parameters for the shear keys can effectively control the maximum displacement of the bearings , reduce the risk of the fall of the beams of the structures in the transverse direction and at the same time ,the seismic damage to the piers under the structures can be also maintained in the allow able range .