广州明珠湾大桥结构体系设计关键技术

Key Technologies for Structural System Design of Mingzhu Bay Bridge in Guangzhou

广州明珠湾大桥主桥采用主跨436 m的中承式钢桁拱桥,双层桥面布置,上层桥面设双向8车道和双侧人行道,下层桥面设双向4车道和管线走廊。该桥设计过程中对主桁体系(两主桁体系、三主桁体系)方案、拱梁组合体系(刚性梁刚性拱、柔性梁刚性拱)方案进行对比分析。考虑结构受力、交通需求等方面,主桁体系最终采用三主桁体系方案,并将上层桥面重车道和下层桥面行车道均靠边桁布置,使每片主桁分担4车道汽车荷载,实现三主桁的受力基本平衡;考虑结构刚度及施工便利性等方面,拱梁组合体系最终采用刚性梁刚性拱方案。经验算,该桥采用三主桁体系、刚性梁刚性拱方案,结构受力满足设计要求。

The main bridge of Mingzhu Bay Bridge in Guangzhou,which is a half-through steel truss arch bridge with a main span of 436 m,accommodates two levels of decks,where the upper deck carries eight-lane roadway and two sidewalks and the lower deck supports 4-lane roadway and utility ducts.During design,the benefits and drawbacks of different types of superstructures were compared,including the truss system(two-main-truss system or three-main-truss system)and the arch-girder composite system(the combination of rigid girder and rigid arch or the combination of flexible girder and rigid arch).To fulfill the load bearing capacity and transportation requirements,the three-main-truss system was finally selected.After modification,the heavy-vehicle lanes on the upper deck and the roadway lanes of the lower deck are all arranged along the lateral trusses to allow each lateral truss to share 4 lanes of vehicle loads,so as to basically balance the loads on the three trusses.To achieve the expected structural rigidity and facilitate construction,the arch-girder composite system that consists of a rigid arch and a rigid girder is determined.It is verified that the combined rigid arch and rigid girder bridge of a three-main-truss system can meet the design load bearing capacity demands.