Design and experiment of FRP-Glulam-UHPC composite girder bridge
Wang Haolei 1,2 Li Hao 1Tang Yuan 1Li Wenqian 1Wang Xiaowei 3Chen Aijun 1
1. Central South University of Forestry & Technology, Changsha 410004, China;
2. Key Laboratory for Wind and Bridge Engineering of Hunan Province, Changsha 410082, China;
3. Jiazhu Architecture Technology Co., Ltd., Shanghai 200092, China
Abstract：The FRP-Glulam-UHPC composite girder bridge which can be fully precast and integrally hoisted was proposed, in order to meet the demands from environment-friendly transition and development of bridge construction in China, and in order to address the ever-existing problems for conventional timber-concrete composite girder, including heavy dead weight, large long-term deflection and inadequate durability, which make it hard to be applied to medium-span bridges. The material consumption and economical efficiency of trial design of 20 m and 30 m span FRP-Glulam-UHPC composite girder bridge were compared with those of conventional timber-concrete composite girder bridge and prestressed concrete girder bridge with the same span; the design value of load combination for the 30 m-span trial bridge were obtained by calculation, and based on the calculated value, the domestic bridge codes and Eurocode 5 were adopted for structural analyses in ultimate limit state and serviceability limit state using the elastic design method. Two test models were designed and manufactured according to the scaled 30m-span trial bridge at the longitudinal ratio of 1∶5, and the detailed experimental study was conducted. The findings show that the dead weight of 20m-span trial bridge girder can be reduced to 72.7% and 48.0% of the conventional timber-concrete composite girder and prestressed concrete girder, respectively, while its life cycle cost is 79.1% and 106.4% of the above two bridge types. The dead weight of 30m-span trial bridge girder can be reduced to 49.3% of the prestressed concrete girder, while its life cycle cost is 134.0% of the prestressed concrete girder. The flexural and shear behaviors of the trial FRP-Glulam-UHPC composite girder bridge meet the requirement of engineering application, while the structural deflection under living load is less than limit value, indicating that the bridge has enough rigidity. The FRP-Glulam-UHPC composite girder bridge designed based on Eurocode 5 has large safety reserve, revealing that the design method is relatively conservative. With the application of FRP, the bearing capacity of the composite girder can be increased by 8.6%, and the failure pattern can be improved with good ductility.
