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 (30–50 m) 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 50 m due 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.