Research on optimal design of deck system in longitudinal prestressed UHPC continuous box girder bridge
Qiu Minghong1 Shao Xudong1,2 Gan Yidong1 Wu Jiajia3 Yang Zhijie4
1. College of Civil Engineering, Hunan University, Changsha 410082, China;
2. Hunan Province Key Laboratory of Wind and Bridge Engineering, Hunan University, Changsha 410082, China;
3. Shanxi Key Laboratory of Bridge Engineering Disaster Prevention and Mitigation, Shanxi Transportation Research Institute, Taiyuan 030006, China;
4. Shanghai Municipal Engineering Design Institute (Group) Co., Ltd., Shanghai 200092, China
Abstract：In order to conveniently arrange the internal prestressing tendon and further improve the performance of deck, the deck system for large-span longitudinal prestressed ultra-high performance concrete (UHPC) continuous box girder bridge was optimized in design, and the novel bridge deck with orthotropic and anisotropic UHPC short-ribbed panel were proposed. With a bridge in Guangdong province taken as an example, the UHPC box girder structure based on orthotropic and anisotropic UHPC short-ribbed deck (OUSRD) was designed and the corresponding experiments were conducted. The results show that: ① compared with the rectangular decks, the self-weight of the deck system with OUSRD can be reduced by 17.0%, and the internal prestressing tendon can be conveniently arranged at the ribs, and compared with the waffle deck panels, the longitudinal stress in the deck panels for the novel desk system can be significantly reduced up to 46.8%, under the premise that the self-weight of the OUSRD is not obviously greater than that of waffle deck panels. ② The entire calculation of the trail design of UHPC box girder with OUSRD meets the requirement of bearing capacity. In the calculation of bridge deck system with characteristic combination of loads, the maximum longitudinal stress in bridge deck and the maximum transverse stress in diaphragm are 2.66MPa and 6.09MPa, respectively. ③ The tests results reveal that the initial crack nominal stress of the short-ribbed specimen is 8.84MPa, and the limit of nominal stress in the design of crack resistance is 10.70MPa. When the transverse stress at the bottom of upper plate of the diaphragm of UHPC box girder is 8.43MPa, the diaphragm is still in the stage of linear elasticity, indicating that the trail design scheme of UHPC box girder with OUSRD may meet the design requirements.
