飞燕式双肢拱肋系杆拱桥优化设计

Optimal Design of Swift-type Double-limb Arch Ribbed Bowstring Arch Bridge

摘要:

某大桥采用4跨飞燕式空间系杆拱体系，跨径布置为36 m+118 m+118 m+36 m=308 m，桥面断面宽度为54.5 m，采用钢梁钢拱结构。主桥的拱肋为分离拱肋，外拱肋平面和吊杆面与铅垂面有一定夹角，为平衡面外弯矩，需对结构进行优化设计。通过对结构总体受力的分析，选定吊杆在梁顶的锚固位置、内外吊杆力分配比例为变量进行优化。结果表明，在构造允许的前提下，内吊杆张拉点从吊杆面开始向道路中心线侧偏移600 mm，内拱吊杆力分配比例提高10%时对拱肋受力更有利。

Abstract:

A bridge is a four-span swift spatial bowstring arch bridge. Its span layout is 36 m+118 m+118 m+36 m=308m. Its deck section width is 54.5 m. It is a steel girder steel arch structure. The arch rib of the main bridge is a separate arch rib, and the plane of the outer arch rib and the surface of the suspension rod have a certain angle with the vertical plane. To balance the bending moment outside the plane, the structure needs to be optimized in design. Through the analysis of the overall force of the structure, the anchoring position of the suspension rods at the top of the beam and the force distribution ratio between the inner and outer suspension rods are selected as variables for optimization. The results show that if the structure permits, the tension point of the inner suspension rod shifts 600 mm from the face of suspension rod to the center line of the road, and when the force distribution ratio of the inner arch suspension rod increases by 10%, the stress of the arch rib is more favorable.