千米级钢-UHPC组合桥面板开口断面组合梁斜拉桥力学性能研究

Mechanical Performance of 1,000-Meter Level Open-Section Composite Girder Cable-Stayed Bridge with Steel-UHPC Composite Bridge Deck

为克服传统钢-混凝土组合梁斜拉桥自重大、跨越能力不足等缺点,解决钢主梁斜拉桥正交异性钢桥面板抗疲劳性差、铺装易损等问题,提出了主跨1000 m钢-超高性能混凝土(UHPC)组合桥面板开口断面组合梁斜拉桥试设计方案;分析了组合梁斜拉桥静力性能及抗风性能;探索了主梁高度H、主梁宽度B、桥面钢顶板厚度t steel、UHPC面板标准厚度t UHPC、UHPC弹性模量E UHPC、钢梁下翼缘板厚度t f等对组合梁斜拉桥静力性能的影响规律及设计主要控制因素。结果表明:UHPC材料大幅提升了组合桥面板的抗压强度和抗裂强度,试设计方案满足结构静力强度要求,且采用较薄的UHPC面板能有效减轻主梁自重;钢梁压应力为主梁静力设计主要控制因素,增加主梁高度或钢梁下翼缘板厚度可有效降低钢梁压应力;采用钢-UHPC组合桥面构造的千米级开口断面组合梁斜拉桥可满足国内部分区域对桥梁颤振稳定性的要求。

In order to overcome the shortcomings of large dead weight and limited spanning capacity for traditional steel-concrete composite girder cable-stayed bridge,and solve the problems of poor fatigue resistance of orthotropic steel decks and damageable pavement for steel girder cable-stayed bridges,the trial design scheme of a 1,000-meter span open-section composite girder cable-stayed bridge with steel-UHPC composite bridge deck was proposed,and the static and wind-resistant performance of the designed bridge was analyzed.The influence rules of the height H and width B of the main girder,the thickness of the top steel plate t steel,the standard thickness of the UHPC slab t UHPC,the elastic modulus of the concrete E UHPC,and the thickness of the lower flange steel plate t f on the static performance of the composite girder cable-stayed bridge and the main control factors of the design were explored.The results show that the UHPC material greatly improves the compressive and crack strength of the composite bridge deck.The trial design scheme meets the structural static strength requirements,and the use of thinner UHPC slabs can effectively reduce the dead weight of the main girder.The compressive stress of the steel girder is the main control factor for the static design of the girder,and increasing the height of the main girder or the thickness of the lower flange plate of the steel girder can effectively reduce the compressive stress of the steel girder.The 1,000-meter level open-section composite girder cable-stayed bridge with steel-UHPC composite bridge deck can meet the flutter stability requirements for bridge in some regions in China.