桥面板干湿混合接缝在组合梁斜拉桥中的应用研究

Study of Application of Hybrid Dry-Wet Joints in Deck Slabs to Composite Girder Cable-Stayed Bridge

为提高组合梁斜拉桥混凝土桥面板横向预应力的施加效率,减少桥面板的纵向裂缝,提出一种可在混凝土桥面板与钢横梁结合前施加横向预应力的干湿混合接缝新型桥面构造。以鳌江特大桥为工程背景,采用通用有限元软件ANSYS建立局部有限元模型,计算比较传统湿接缝桥面板和新型干湿混合接缝桥面板的预应力施加效率。在鳌江特大桥上设置试验段应用干湿混合接缝新型桥面构造,现场测试施工阶段混凝土桥面板应力变化情况。结果表明:组合梁斜拉桥采用干湿混合接缝的新型桥面构造,可实现在混凝土桥面板与钢横梁结合前施加横向预应力,横向预应力施加效率提高了约70%,可减少混凝土桥面板纵向开裂;实桥测试中干湿混合接缝桥面板纵横向应力满足规范要求。

To improve the application efficiency of transverse prestressing to concrete deck of composite girder cable-stayed bridge and reduce the longitudinal cracks in the deck, a deck structure with hybrid dry-wet joints that can be transversely prestressed before the connection of concrete slabs and steel cross beams is proposed. The Aojiang River Bridge was cited as an example for the study. The finite element software ANSYS was used to establish the local finite elementmodels, to compare the application efficiency of prestressing in the traditional deck with wet joints and the new deck with hybrid dry-wet joints. A testing segment was added to the Aojiang River Bridge for the application of the new deck structure with hybrid dry-wet joints, and the variation of stresses in the concrete deck in the construction stage was tested on site. The results show that when the new deck structure with hybrid dry-wet joints is used, the transverse prestressing can be applied before the connection of the concrete deck and steel cross beams, the application efficiency of transverse prstressing is improved by 70%, as a result, the longitudinal cracking in the concrete deck can be reduced. Tests for real bridge show that the transverse prestressing in the deck with hybrid dry-wet jointsmeet the code requirements.