主跨460m协作体系斜拉桥约束体系研究

Study on Constraint Systems for Cooperative System Cable-Stayed Bridge with Main-span of 460 m

巢湖大桥采用主跨460 m协作体系斜拉桥体系,跨径布置为(54+216.5+460+216.5+65+55+55)m,采用钢-混凝土组合梁,"人"字形混凝土主塔,拉索采用空间扇形拉索布置,主塔采用哑铃形承台,辅助墩及边墩采用分离式承台,基础采用钻孔灌注桩形式。现对巢湖大桥的竖、顺、横向约束体系进行比选研究,最终确定竖向塔梁间采用"0"号索、顺向塔梁间采用固定支座+黏滞阻尼器限位装置、横向边墩处采用摩擦摆式减隔震支座的全桥约束体系,以改善全桥结构在静力及地震作用下结构受力,获得相对最优的结构静动力力学性能,减小全桥材料用量,提高工程经济性。

Chaohu Bridge was designed as a cooperative system cable-stayed bridge,with a span arrangement of 54+216.5+460+216.5+65+55+55 meters.The cable-stayed bridge was composed of steel-concrete composite girders with a total height of 3.0 meters,inverted Y shaped concrete pylons and spatial fan-shaped cables.Dumbbell type pile cap was designed for the towers and separate pile caps for the piers.Foundation was made of castplace-piles.Various restraint systems in the vertical,longitudinal, and transversal directions were all compared in this paper.Finally,an optimal fullbridge restraint system was selected,with a "0" cable between vertical tower and beam in the vertical direction.A fixed constraint at NO pylon and viscous dampers at both pylons between tower and beam were set in the horizontal direction.Friction pendulum seismic isolation bearings were adopted on side piers in the transverse direction,which would reduce the structural stress of the bridge structure under static and earthquake action,obtain a relatively optimal static and dynamic mechanical properties,reduce the amount of bridge materials,and improve engineering economy.