【摘要】 基于平衡荷载值确定双向张弦实腹梁结构的形状,由特制花篮螺丝和改装的U型绳卡分别模拟拉索张拉端和锚固端,采用多点分配梁杠杆集中加载与跨中直接吊挂加载相结合的加载方案,设计了一个索形优化后的双向张弦梁整体结构索力静载试验.试验结果显示,双向张弦梁下部双向预应力索以两个方向交叉进行分步张拉且张拉顺序由跨中向跨端进行为宜;经过索网形状优化之后,当竖向荷载增大到设计平衡荷载值时,双向张弦梁双向各索索力值相近,分布均匀,明显改善受荷阶段结构中的索力分布.双向张弦梁下弦索对非对称荷载尤其是二分之一跨分布形式较为敏感,可能出现边跨索力超过同级全跨荷载下的现象.更多还原

【Abstract】 The shape of bidirectional beam string structure is determined by the balancing load value. In the test, the tension end was simulated by special turnbuckle and the anchor end was simulated by modified U type rode cappel. An experimental model of bidirectional beam sting structure after the optimization of cable shape was designed, which adopted a load scheme combining lever concentrated loading through distributive girder on multiple spots and directly hanging loading in the center of the structure plane. The test result showed that it was appropriate for the bidirectional prestressed cables, the lower part of bidirectional beam string structure, to pull step by step in two intersecting directions, with the tension sequence from midspan to the end. When the vertical load increased to the balancing load value, the force of each cable in two directions was almost equal. Cable forces were evenly distributed, which improved the cable force distribution in loading stage. The cable net of bidirectional beam sting structure was susceptible to asymmetrical live load, especially to half span load, which led to a higher force of sidespan cable than that under full span load.更多还原