【摘要】 该文采用截面内力积分程序,研究某圬工拱桥精细化实体单元有限元模型在左桥台施加不同水平向位移的工况下,主拱圈和拱脚的关键截面轴力、剪力和弯矩的分布和发展趋势,并根据该趋势预测圬工拱桥的倒塌顺序,得出随着圬工拱桥桥台的滑移,离滑移端最近的拱圈受力最不利;其次,利用OpenSEES作为桥梁渐进倒塌破坏分析的求解内核,对大应变TLFD8nBrick单元进行二次开发,开发了相应的3D实体单元及几何非线性动力分析方法,并以应变作为单元的失效准则,通过单元生死技术模拟圬工拱桥的损伤破坏,实现拱桥的渐进式垮塌模拟,倒塌顺序与内力分析预测结果一致。结果表明:对不同工况下桥梁关键截面的内力发展情况进行研究,可有效的揭示圬工拱桥垮塌机理;其次,针对OpenSEES中的大应变单元进行二次开发,能准确模拟桥梁构件渐进破坏过程;最后采用3D图形动画可直观显示桥梁渐进倒塌过程。更多还原

【Abstract】 This paper studied the distribution and development of axial force,shearing force,and bending moment in the key section of a masonry arch bridge under different horizontal displacements of the left abutment of the bridge by using the sectional internal force integral program.According to the collapse analysis of the masonry arch bridge,the critical stress position was found to lie in the closest arch away from the sliding end of the slipped abutment.Moreover,OpenSEES was used to perform the progressive collapse analysis,in which the large strain TLFD8nBrick element was developed,the 3D solid element was created and the geometrically nonlinear dynamic method was established.Taking the strain as the index of failure,the simulation of the progressive collapse of the masonry arch bridge is performed by modeling the initial damage and using the "killing or activating elements" technology.The results show that this research can effectively reveal the collapse mechanism of the masonry arch bridge.In addition,the further development of the large strain element in OpenSEES can accurately simulate the progressive collapsing process of the bridge.更多还原