【摘要】 长益复线潇湘北路跨线桥为主跨105 m的曲线变宽钢-混凝土叠合板组合连续梁桥，为提升该桥受力性能，综合应用了叠合板技术、预应力锚固区UHPC桥面板技术、抗拔不抗剪(URSP)连接件技术以及双重组合技术。除预应力锚固区外，其余区段桥面板均采用由底层混凝土预制板和上层混凝土现浇层组成的叠合板，可在保证桥梁整体性和无支模施工的同时，使收缩徐变作用下混凝土板和钢梁应力较全现浇板降低。预应力锚固区采用UHPC桥面板，并在边跨增设1道预应力束，可有效避免该区域混凝土的损伤。在中支点两侧各32 m范围布置URSP连接件，可释放抗剪约束的同时保留抗拔作用，配合预应力技术可将频遇组合下的负弯矩区混凝土板压应力水平控制在1.12 MPa以内。在中支点两侧各20 m范围内负弯矩区设置混凝土底板与钢梁底板进行组合(双重组合技术),并结合组合梁顶部URSP连接件技术，可使负弯矩区组合梁形成一个倒置的“正弯矩组合梁”效应，从而降低负弯矩区钢梁底板应力。更多还原

【Abstract】 The Xiaoxiang North Road Overpass carrying a section of the Second Changsha-Yiyang Expressway is a curved continuous girder bridge with a main span of 105 m. The overpass features the varying-width superstructure that consists of steel girders and composite deck that incorporate a lower layer of precast concrete panels and an upper layer of cast-in-situ concrete panels, localized with cast-in-situ UHPC deck panels at the prestressing anchor zones, to ensure the entirety of the bridge while reducing the stresses in the concrete panels and steel girders under the shrinkage and creep effects, compared with fully cast-in-situ panels, when the concrete is cast without supporting formwork. Techniques, including the application of composite deck panels, UHPC deck panels at prestressing anchor zones, utilization of uplift-restricted and slip-permitted(URSP) connectors and creating double composite action, were selected to enhance the load bearing capacity of the overpass. In the prestressing anchor zones, UHPC is cast instead of normal concrete, and a prestressing tendon is tensioned to effectively prevent damages of concrete. In the two 32-m long zones(counted from the intermediate support),the URSP connectors, which releases the shear forces in these zones while sustaining the uplift forces, and can, together with the prestressing technique, control the compressive stress in the hogging moment zone within 1.12 MPa under the frequent load combinations. In the two hogging moment zones counted from the intermediate support, extra concrete slabs are compositely connected with the steel bottom plates to achieve double composite action, together with the URSP connectors in the deck panels, to create an inversed "composite girder with positive bending moment" in the hogging moment zones. As a result, the stresses in the steel bottom plates in the hogging moment zone can be reduced.更多还原