基于板元框架法的钢底板波形钢腹板组合箱梁畸变效应分析

Analysis on Distortion Effect of Trapezoidal Composite Box Girders with Corrugated Steel Webs and Steel Bottom Plates Based on Plate Element Frame Method

为分析钢底板波形钢腹板梯形组合箱梁的畸变效应,利用圣维南原理考虑顶底板对波形钢腹板的约束作用,将组合箱梁等效为钢箱梁的过程中保持面内外抗弯刚度不变,基于板元框架法建立畸变控制微分方程并导出克雷洛夫函数形式的通解。结合数值算例的对比分析验证所提方法的合理性,并研究腹板俯角和梁高变化对畸变双力矩的影响。结果表明:相较于完全忽略腹板的面内抗弯刚度,考虑顶底板对腹板的约束作用更合理;波形钢腹板和钢底板对箱梁的畸变翘曲刚度和横向框架刚度均有较大程度的削弱;传统波形钢腹板组合箱梁的畸变翘曲应力是普通混凝土箱梁畸变翘曲应力的1.98倍,钢底板波形钢腹板组合箱梁的畸变翘曲应力可达传统波形钢腹板组合箱梁畸变翘曲应力的15.31倍;跨中截面附近的双力矩随腹板俯角变化较小,其他截面处的双力矩随腹板俯角的增大而逐渐减小;畸变双力矩随梁高的增大而逐渐增大,且其最大值位置也随之发生变化。

In order to analyze the distortion effect of trapezoidal composite box girder with corrugated steel webs and steel bottom plates,the restraint effect of top and bottom plates on corrugated steel webs is considered.Maintain the inplane and out-of-plane bending stffness unchanged when the composite box girder is equivalent to a steel box girder.Based on the plate element frame method,the distortion governing differential equation is set up based on plate element frame method and the general solution of Krylov function is derived.Combined with the comparative analysis of numerical examples,the rationality of this method is verified,and the influence of web depression angle and girder height on bi-moments is studied.The results demonstrate that it is more reasonable to consider the restraint effect of the top and bottom plates on the webs than to ignore the in-plane bending stiffness of the webs completely.As distortion warping stiffness and transverse frame stiffness of box girder is greatly weakened by corrugated steel web and steel bottom plate,the distortion warping stress of traditional corrugated steel web composite box girder can reach 1.98 times that of ordinary concrete box girder.And the distortion warping stress of corrugated steel web composite box girder with steel bottom plate can reach 15.31 times of that of traditional corrugated steel web composite box girder.The bi-moment near the mid-span section changes litle with the web depression angle,and the bi-moment in other sections decreases gradually with the increase of the web depression angle.The distortion bi-moment increases slightly with the increase of girder height,and its maximum position changes.