斜腹板薄壁箱梁横向内力分析及其参数影响研究

Research on Transverse Internal Force and Its Parameter Influence of Thin-walled Box Girders with Inclined Webs

基于薄壁箱梁畸变理论,考虑畸变位移与框架位移之间的协调条件,建立斜腹板单箱单室箱梁横向内力计算的解析公式。在刚性支承框架分析基础上,通过引入横向弯矩修正系数,反映箱梁畸变变形对横向弯矩的影响。详细分析竖向偏心荷载作用下,斜腹板倾斜程度及梁高变化对横向弯矩的影响规律。研究结果表明:按文中公式求得的箱梁横向弯矩与有限元软件Ansys壳单元计算结果吻合良好,从而验证了本文公式的正确性;在通常的偏心荷载作用下,当斜腹板的俯角约为12°,箱室高宽比约为0.55时,顶板的横向弯矩峰值最小;随着俯角及高宽比的增大,离偏心荷载较近的顶板角点横向弯矩修正系数逐渐增大,而较远的角点横向弯矩修正系数急剧减小,当俯角及高宽比很大时修正系数均趋近于1。

Based on the distortion theory of thin-walled box girders,considering the compatibility conditions between the distortion displacements and frame displacements,the analytic formulas to calculate the transverse internal force of single-cell box girder with inclined webs were established.On the basis of rigid-supported frame analysis,a modification factor for transverse bending moment was introduced to reflect the influence of distortion deformation of box girder on the transverse bending moment.The influences of the variations of webinclination degree and beam depth on the transverse bending moment under vertical eccentric load were numerically analyzed in detail.Research results show that the transverse bending moments of the box girder obtained by applying the derived formulas are in good agreement with those by the shell element in finite element software Ansys,validating the correctness of the formulas.The peak value of the transverse bending moment of top slab is the smallest when the depression angle of the web is approximately 12°and the depth width ratio of the box is approximately 0.55 under usual eccentric load.The modification factor for the transverse bending moment at the top slab corner closer to eccentric load increases gradually while that at the corner away from eccentric load decreases sharply with the increase of the depression angle and the depth width ratio.Both the modification factors tend to be 1when the depression angle and the depth width ratio are very large.