预制T梁桥和组合式U梁桥构造设计的对比分析

Contrastive Analysis of Structural Design of Precast T Beam Bridge and Composite U Beam Bridge

为了提高我国预制标准梁桥的构造设计技术,比较分析了我国预制T梁桥和英国组合式U梁桥的异同:T梁桥由预制T梁、湿接缝组成,多通过湿接缝横向连接预制梁体,纵向连续主要有结构简支、桥面连续,先简支后连续2种;桥面铺装混凝土层是其重要的构造;预制时带有一部分桥面板,方便梁体架设。组合式U梁桥由预制U形梁、现浇端横梁、现浇桥面板组成,通过现浇桥面板和端横梁横向连接预制梁体,纵向用普通钢筋在结构范围内形成连续或部分连续;桥面铺装不需混凝土层,桥面板以上直接铺设防水层和沥青混凝土;在预制时不带桥面板,架设梁体有一定困难。分析表明:英国组合式U梁桥便于施工、质量易保证,且能提高桥梁的整体强度和刚度以及耐久性,但架设方法还有待研究。

In order to improve the structural design technique for standard precast beam bridges in China, the similarities and differences between precast T beam bridges in China and composite U beam bridges in Britan were compared and analyzed. The T beam bridge is com- prised of precast T beam and wet joints, the precast beams are transversely linked by wet ioints, but longitudinally, the bridge usually acts as a continuous structure, the main continuous forms include the type of the simply-supported structure with continuous bridge deck and the type of transforming from a simply;supported structure to a continuous one. The concrete layer in the deck pavement is an important component and the beam is usually precast with partial bridge deck for the convenience of erection. Structurally, the composite U beam is composed of precast U beam, cast-in-situ end cross beam and cast-in-situ bridge deck. The precast beams are transverse- ly connected through cast-in-situ bridge deck and the end cross beam, longitudinally, common re- inforcement is installed inside the structure to realize the continuity or partial continuity of the beam. No concrete layer is needed for the bridge deck pavement and the waterproof layer and as- phalt concrete are directly paved on the bridge deck. The bridge deck is not precast, so the erec- tion of the beam is, to a certain extent, a very challenging work. The results of the analysis show that the British composite U beam is convenient for construction, the construction quality is easy to control, and the entire strength, rigidity and durability of the bridge can be enhanced. But the erection method is still controversial.