以一座典型的体外索加固的预应力混凝土T 型刚构桥为工程背景，采用空间有限元分析了加固后的T 型刚构桥的静动力性能，并进行了试验研究，可供今后加固类似工程参考。

A comprehensive investigation of the stochastic response of the approach bridge of Sutong Yangtze River Bridge-PC continuous rigid frame box girder bridges subjected to spatially varying ground motions is completed. A frame member system model considering the geometrical non-linearity caused by the dead load state and the soil-foundation-structure interaction effect is presented. The wave passage, incoherence and site-response effects are separately discussed in detail. It is pointed out that each component of the spatially varying ground motion model has important effects on the dynamic behavior of the bridge. Therefore, the variability of the ground motions should be considered in the design of this kind of bridges.

提出了分析空间梁拱组合式桥梁荷载横向分布的弹性支承连续梁法,实例计算及试验结果表明：所提出的方法计算的荷载横向分布系数与实测挠度值反算的荷载横向分布系数基本吻合，对城市道路以三块板布置的空间梁拱组合式桥梁结构，一般以靠近机动车道内侧梁拱拱片的横向分布系数较大、并控制设计。

The prestressing load is one of the key loads in P.C.bridge under normal service stage. In modern P.C.bridges, besides the longitudinal prestressing forces, the transversal and vertical prestressing forces are often used. The spatial stresses effect caused by prestressing force is very evident and the behaviour of structure is complicated in the P.C.bridges. The traditional elementary beam theory can not analyze the spatial stresses effect. Based on the conventional 3D isoparametric finite element method, one new, more convenient and effective element—degenerated solid element for analyzing all kinds of complicated structures is presented. It assemble the advantages of the shell element and 3D isoparametric element. In the end, a typical three-span P.C. continuous rigid-frame box girder bridge is analyzed by the method. Influence of prestressing force on spatial effect is explored. The analysis results indicate that the degenerate solid element is a effective and practical method.

Based on one typical cable-stayed bridge with mono-tower and mono-cable plane, the shear lag effect in the kind of bridge with multi-cell box girder is analysed by spatial finite element method. The influence of some factors such as the type and transverse acting location of external load on the shear lag effect is explored. Some useful conclusions are drawn through this study.