简支转连续桥梁体外预应力拼装接头技术

Externally prestressed prefabricated joint technology in simply-supported continuous bridge

为了改进简支转连续体系桥梁的后连续工艺,采用体外预应力技术将简支梁和预制接头进行拼装,形成后连续体系桥梁.通过室内试验与有限元数值分析,对体外索预制拼装接头的构造及相应力学性能进行探讨.数值分析时采用接触单元模拟接缝间的相互作用,并考虑了材料非线性和接触非线性.室内试验与数值计算结果表明,对于使用体外索预制拼装接头的简支转连续梁桥,荷载-挠度曲线呈现出三折线刚度特征,增大预应力可抑制接缝开裂,并且双剪力键的受力较牛腿的受力均匀.可按照弹性理论计算结构挠度,设计时宜适当增加体外预应力量值且优先采用双剪力键接头形式.

To improve the post-connection craft of simply-supported continuous bridge, the externally pres- tressed technology is employed to connect simply supported beams and prefabricated joints in series to constitute the continuous beam. By the means of indoor test and numerical analysis, the structural style and relative mechanical properties at this joint are studied. At the same time, the contact element which may simulate in- teractions between joints is used and the influences of material nonlinearity of concrete and geometric nonlin- earity of structure are taken into account in computation models. The results indicate that an approximate tri- ple-fold line is presented in the load-deflection curve of the simply-supported continuous bridge and the in- crease of prestressing force can suppress cracking at joints, on the other hand, the stress of double shear keys is more uniform than that of single shear key. Therefore, the deflection of this structure can be computed by e- lastic theory approximately, and the design adopting relative large prestressing force and double shear keys joint is suitable to the simply-supported continuous bridge.