波形钢腹板箱梁桥异步施工节段足尺模型试验研究

为了研究波形钢腹板箱梁桥异步施工过程中结构的受力性能,验证各关键部位的安全性,以奉化江大桥主桥为背景,针对该桥异步施工过程中的受力最不利工况——主梁16号节段的底板浇筑工况设计制作足尺模型(长7.2m、宽2.3m),采用两点加载方式进行静载试验,研究施工荷载作用下梁体挠度、波形钢腹板侧向变形、波形钢腹板及钢翼缘板的应力分布。结果表明:施工荷载作用下,混凝土顶、底板均未出现裂缝,波形钢腹板剪应力远小于其抗剪强度设计值,波形钢腹板自承重异步施工可满足结构受力要求,具有足够的安全储备;波形钢腹板作为自承重结构在竖向荷载作用下产生的竖向挠度及侧向变形较大;波形钢腹板上翼缘板挂篮作用点处为结构受力关键部位,施工时应对其进行局部加强。

Segmental Full-Scale Model Test for Asynchronous Construction of Box Girder Bridge with Corrugated Steel Webs

In order to investigate the mechanical properties of box girder bridge with corrugated steel webs and to verify the safety of the key structures during the asynchronous construction process,we designed and prepared a full-scale model with a length of 7.2 m and a width of 2.3 m in accordance with casting the No.16 section base slab of main girder,which is in the most unfavorable loading conditions of the bridge,during the rapid asynchronous construction period based on the Fenghua River Bridge.The static load test was carried out by a two-point loading method to study the deflection of the girder,the lateral deformation of the corrugated steel webs,the stress of the corrugated steel webs,and steel flanges under the construction load.The results show that,under the construction load,no cracks occur in the top and base slabs of the concrete,and the shear stress of the corrugated steel webs is much less than the design value of the shear strength,indicating that the self-supporting asynchronous construction of corrugated steel webs can meet the requirements of structural stress and has sufficient safety reserve.The corrugated steel web,as a self-supporting structure under vertical load,has a remarkable vertical deflection and lateral deformation.The action point of hanging basket at the upper steel flange plate of the corrugated steel webs is the key part,which should be locally strengthened during construction.