珠机城际铁路公铁同层合建桥方案比选

珠机城际铁路金海特大桥跨磨刀门水道主通航孔跨径为3×340 m,采用公铁同层布置,结合桥址区建设条件,对桥型方案进行研究比选。从桥式上对比多塔斜拉桥方案与钢桁拱桥方案,由于设计基准风速大、台风频发、多主跨等因素,考虑经济性、施工难度及施工过程抗风稳定性,最终确定采用(58.5+116+3×340+116+58.5)m多塔斜拉桥方案。在此基础上,针对多塔斜拉桥,对桥塔中置和桥塔外包方案,从结构受力、施工、经济性、景观性等进行综合比选,最终推荐采用温度效应小及抗震性能好、施工工期短、经济性相当、景观效果好的桥塔中置方案。

Scheme Comparison for a Bridge on Zhuhai Urban Airport Mass Rapid Transit Accommodating Railway and Vehicle Traffic on Same Deck

The part of Jinhai Bridge on Zhuhai Urban Airport Mass Rapid Transit that crosses the Modaomen Waterway consists of three main navigational spans of 340 m.The bridge is required to have a deck accommodating both the railway and vehicle traffic.Based on the construction conditions at the bridge site,the bridge type schemes were studied.The schemes of multi-pylon cable-stayed bridge and steel truss arch bridge were structurally compared.Due to that the great design benchmark wind speed,frequently-visited typhoon and the demand for multiple main spans,a multi-pylon cable-stayed bridge with spans of 58.5 m,116,3×340,116,and 58.5 m was finally chosen,taking account of economy,construction challenges and the wind-resistant stability in the construction process.For the multi-pylon cable-stayed bridge,the pylons can be arranged in the central zone of the deck or in a way enveloping the main girder,and the two layouts of pylons were comprehensively compared from aspects of load bearing behavior of the structure,construction,economy and aesthetic effect.At last,the scheme of arranging the pylons in the central zone of deck was chosen,which is considered bringing minimal temperature effect,good seismic performance,short construction time,significant economic benefit and good aesthetic effect.