中文摘要：

以湖南长沙湘江北大桥西引桥为工程实例,对既有简支铰接空心板梁桥结构状况动力评估方法进行了研究。首先根据梁格法基本原理,通过使虚拟横梁在同一铰接缝处的梁端竖向约束相互耦合来模拟纵向铰接缝,提出了改进的梁格模型,建立了简支铰接空心板梁桥动力特性空间分析模型,计算得出了桥梁结构的动力特性;然后通过实桥动力试验验证了计算模型的正确性,介绍了动力评估试验内容、测试方法以及测试结果。分析结果表明：该桥的动力系数都在规范要求内,桥梁结构状况良好,本文方法可为既有简支铰接空心板梁桥的结构状况评估提供有效手段。

英文摘要：

A dynamic assessment method about existing simply-supported hinge joint celluar slab bridges was researched with the project of west approach bridge of North Bridge over Xiangjiang River in Changsha, Hunan province as an example. Firstly, based on the basic principles of grillage method, an improved grillage model was put forward, which made the vertical constraint of crossing beam ends couple at the same hinged joint to simulate longitudinal hinge joint, the space dynamic characteristic analytical model of the bridge was established and the dynamic characteristics of the bridge were calculated. Then, authors proved the correction of the model through the dynamic test and introduced the dynamic assessment test contents and test methods and test results. The analytical results show that the dynamic coefficients can meet the needs of the specification and the bridges are in good condition. This method provide an effective means for the assessment of the existing simply-supported hinge joint slab bridges.