薄壁箱梁的剪切附加挠度分析

Analysis of Shear Additional Deflection of Thin-walled Box Girders

从薄壁箱梁弯曲剪力流出发,分析箱梁的应力应变关系,并与初等梁理论相结合,导出适合薄壁箱梁的合理剪切参数,从而简化箱梁腹板剪切附加挠度的计算.采用对剪切附加曲率的积分及能量变分法,导出腹板剪切附加挠度和考虑全截面剪切变形的箱梁挠度计算公式.通过剪切附加挠度与弯曲挠度的对比,分析影响翼板和腹板剪切变形的主要因素.建立了ANSYS空间模型算例,结果表明,按本文的计算式所得挠度与ANSYS结果吻合良好;当宽跨比、高跨比较大时,均布荷载作用下的简支箱梁跨中因剪切变形产生的附加挠度将达弯曲挠度的22%以上,应予以重视.

Based on the bending shear flow of thin-walled box girder,the paper analyzes the stress-strain relationship of the box girder.Combined with the elementary beam theory,the reasonable shear parameters for thin-walled box girders are derived so that the calculation of shear additional deflection of box girder web plate is simplified.By integrating the shear additional curvature with the energy variation principle,the web shear additional deflection and the deflection formula considering the effect of whole cross-section shear are obtained.The main factors affecting the deflection of flange plate and web plate are studied by comparing the additional shear deflection with the bending deflection so the model example with ANSYS software is established.The results show that the deflection obtained from the calculation formula in this paper is in good agreement with the calculation results from ANSYS software.When the width-span ratio and the depth-span ratio are relatively large,the shear additional deflection in mid-span section will be above 24% of the bending deflection when the simply supported beam is subjected to uniformly distributed load.