中文摘要：

结合在役桥梁特点，依据桥粱实例，分析建立了既有连续钢桁梁桥加固前、后平面和空间计算模型。通过模型计算结果与实测资料对比分析，以及空间与平面模型计算结果的比较，表明空间计算模型为合理的工作模型。空间计算模型采用空间梁单元模拟桁架桥杆件，可以考虑弯曲次内力和结构空间受力行为，能够比较真实地实现连续桥梁的工作状态模拟。该模型为桥梁加固后安全寿命评估奠定了基础。

英文摘要：

Combined with the characteristics of existing bridges nite-element model （FEM） of actual continuous steel truss bri , the corresponding 2-D and 3-D fi dge were established before and af ter the bridge beeing strengthened. The results calculated by the this model was compared to the one of field measuring, the comparison showed that 3-D FEM was the appropriate working mod el. Considering secondary bend force of structure, 3-D FEM can use 3 D elastic beam element to simulate truss members, which can accomplish actually mechanic behaviors simulation of existing continuous steel truss bri tigue life of strengthened dges. The space model can be employed to evaluate the remaining fa bridges. 8 tabs, 6 figs, 6 refs.