梯形箱梁无边梁变厚度行车道板等代刚度的差分解

FINITE DIFFERENCE SOLUTION FOR CONTILEVER SLAB WITH VARIABLE THICKNESS IN TRAPEZOIDAL BOX GIRDER WITHOUT EDGE BEAM

长悬臂预应力混凝土梯形箱梁,目前在国内外桥梁建设中被广泛采用。由于受荷要求,在已建成的桥梁中有的已经超过5m,悬臂厚度用变厚度而在悬臂根部还应设有加腋。我国公路钢筋混凝土及预应力混凝土桥涵设计规范JTJ-023-85规定悬臂板有效分布宽度a=a_2+2H+2b′,这个规定适用于无限宽的等厚度板,对变厚度显然不适用,其中b′是从轮着地长度外边缘向外45°分布也不妥当。本文首先对过去的研究作一回顾与评述,然后应用等代刚度差分法,对变厚度行车道板的有效宽度进行分析与计算。并与消除差分中虚节点的修正法做了对比。最后对悬臂行车道板(根部全固结)的有效分布宽度提出建议,供修订规范时参考。

Long cantilever slabs are often used in trapezoidal box girder bridge, Thehighway bridge design specification in our country provides the design formulafor constant thickness, but no provisions are related with variable thickness.In this paper, applying Finite Difference and revised Finite Difference, theeffective width of load on the cantileve deck are analyzed. Equivalent Rigidityof slab under the applied load is being used through the analysis. Comparisonsare made with two-related methods and preliminary. Suggestions are given foroffice design work.