大跨悬索桥桁架加劲梁的选型和设计

归纳国内外已建和在建的桁架加劲悬索桥的一般情况，论述了加劲梁的受力特点，分析了主桁、横联、水平联和桥面的各可选型式的特点，根据统计数据得到了若干设计参数的经验取用规则。分析研究表明，在大跨度悬索桥中，抗扭能力是桥面结构最主要的加劲要求；加劲桁梁的高跨比与桥面设计风速的平方存在线性回归关系，因此可以由跨径和风速参数来初步拟定桁高；桥面设置一定透空是桁式加劲梁增进气动稳定性的有效和简便手段；上下平联采用K形撑比X形撑获得的扭转刚度要小，但K形撑不参与主桁竖弯，受力状态相对简单。对比混凝土桥面、钢桥面和合成型钢桥面3种方案的技术经济特点，合成钢桥面有助于提高加劲梁扭转性能和结构轻型化。

Type Selection and Design of Stiffening Trusses for Long-span Suspension Bridge

The status of newly constructed and in-service truss-stiffened suspension bridges was summarized.The principal working behaviors of stiffening truss were disserted.The structure features of the types of main truss,transverse bracing,lateral bracing and the deck were expounded.Based on statistic data,the criterion on determining on the key design parameters of stiffening truss was given.It is concluded that(1) the torsion resistance is the most important stiffness requirement for the long-span suspension bri...