波形或桁架式钢腹板的预应力钢混组合桥主梁的安全性能和使用性能评估

在许多国家,预应力混凝土箱梁被认为是中等跨径(30～50m)混凝土梁最有效的结构形式。但是当混凝土梁的单跨长度超过50m时,相对钢梁,混凝土箱梁自重问题成为其最大约束。因此,在韩国,中等跨径桥梁主要采用钢箱梁。在20世纪,研究者们多次尝试提高预应力混凝土箱梁结构的有效性,最终采用混凝土-钢混合梁以减轻结构自重。但是,混合桥采用不同类型钢腹板及不同连接形式,会引起结构安全性能和使用性能的变化。为了全面了解钢腹板梁及钢腹板连接形式的性能,对5根带腹板的预应力混凝土梁进行静力荷载试验。这5根试件中,有2根混合梁采用波形钢腹板,而另3根采用桁架式钢腹板。结果显示:通过加强钢腹板与预应力筋的连接节点,可以改善使用性能相关问题(开裂荷载和挠度)及安全性能相关问题(刚度和极限承载力)。

Structural Safety and Serviceability Evaluations of Prestressed Concrete Hybrid Bridge Girders with Corrugated or Steel Truss Web Members

Prestressed concrete box girders have been regarded as the most favorable medium span(30～50m)concrete girder type in many countries,but they have a crucial limitation compared to steel girders in that a single span length cannot be extended over 50mdue to its relatively heavy self-weight.As a result of this restriction,the majority of medium span girder bridges constructed in Korea have been steel box girder types.In the 20th century,numerous attempts have been made to improve the structural efficiencies of prestressed concrete box girders using concrete-steel hybrid subcomponents to reduce the weight of the superstructure.However,the behaviors of hybrid bridge girders with various steel web types and connection joints have caused safety and serviceability problems.Therefore,in order to fully understand the behaviors of steel web girders and the effects of steel web connection joints,a static loading test was conducted on five prestressed concrete hybrid girders with steel web members.Result comparisons for structural safety and serviceability were also performed.The five girder specimens were two hybrid girders with corrugated steel webs and three hybrid girders with steel truss webs.The study results showed that the serviceability issues such as cracking load and deflection and the safety issues such as stiffness and ultimate load capacity can be improved by modifying the steel web members and connection joints of concrete slabs and tendons.The study results are discussed in detail.