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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)。
In many countries, prestressed concrete box girders are considered as the most effective structural form of medium-span (30-50 m) concrete beams. However, when the single span length of concrete beams exceeds 50m, the problem of self-weight of concrete girders becomes the maximum constraint relative to steel girders and concrete girders. Therefore, in South Korea, medium-span bridges mainly use steel box girders. In the 20th century, researchers tried many times to improve the effectiveness of prestressed concrete box girder structures, eventually using concrete-steel hybrid beams to reduce the weight of the structure. However, different types of steel webs and different types of connections are used in hybrid bridges, which can cause changes in structural safety and serviceability. In order to fully understand the performance of steel webs and steel web connections, five static load tests were carried out on five prestressed concrete beams with webs. Of the five specimens, two hybrid beams use corrugated steel webs and the other three use truss-type steel webs. The results show that problems related to serviceability (cracking load and deflection) and safety-related issues (stiffness and ultimate bearing capacity) can be improved by strengthening the connection of steel webs to tendons.