空间预应力钢束精细化有限元建模方法

Refined Finite Element Modeling Methodof Spatial Prestressed Steel Beam

为了建立同时包含平弯和竖弯的空间曲线预应力钢束连续平滑模型,在有限元分析中考虑空间预应力钢束的各项力学效应,提出了基于相贯线的空间预应力钢束精细化建模方法,确定了钢束、孔道与梁体三者之间的节点对应连接方式,并给出了相应的建模程序.首先采用辅助实体相贯的方法,建立了空间预应力钢束的连续平滑几何模型;然后沿该空间曲线建立孔道实体,并与混凝土主梁进行布尔运算,实现钢束、孔道与梁体三者之间的节点对应连接.以贵州红水河特大桥钢-混结合段的建模与分析为例,计算结果表明:与传统的约束方程法相比,采用本文方法计算得到的梁体最大局部压应力降低26.3%,应力集中现象明显改善;钢束有效应力分布平顺、无波动,更符合实际情况.

In order to establish a continuous smooth model of spatial prestressed steel beam include both horizontal and vertical curvature, to consider the mechanical effects of spatial prestressed steel beam in finite element analysis, the refined finite element modeling method of spatial prestressed steel beam based on intersecting line was proposed, so the connection mode of the n odes b e t w e e n the spatial prestressed steel beam, duct and concrete girder could be ascertained, and the corresponding modeling procedure was given. The continuous smooth geometric model of spatial prestressed steel beam was established by the intersecting auxiliary bodies. The nodes corresponding relationship between steel beam, duct and concrete girder were achieved by establishing the solid model of duct and performing Boolean operations with main girder. Take the finite element m o d eling a n d analysis of the steel- concrete joint section of the Hongshui River bridge in Guizhou as an example, the results show that the maximum local stress of girder decreased by 26. 3% ,and the stress concentration is i m p r o v e d obviously compared with the traditional constraint equation method, the effective prestress distribution of steelbeam is smooth, non-oscillating, the proposed method is more in line with the actual situation.