板梁桥“单板受力”的数值分析

目前 ,在小跨径的公路桥涵中普遍出现了“单板受力”问题 ,给行车安全带来了隐患。针对这一现象 ,笔者主要借助有限元软件ANSYS对板梁桥的“单板受力”现象进行了数值模拟。首先 ,采用梁单元建立板梁桥的仿真模型 ,分析了不同跨径板梁的荷载横向分布规律 ;然后 ,根据板梁桥的受力特性和造成“单板受力”的原因 ,提出了缓解和避免“单板受力”的 5种加固方案 ,并采用实体单元建立板梁桥的空间模型 ,比较并分析了各加固方案位移、应力等力学性能 ;随后 ,详细分析了铰缝处混凝土的横向应力分布规律 ,并建议应采用新老混凝土之间的粘结强度作为标准校核铰缝的横向应力 ;最终 ,根据各加固方案的优缺点 ,提出了解决“单板受力”问题的可行方案。

Numerical Analysis on "Single Plate Bearing" of Plate Girder Bridge

Nowadays the “single plate bearing” commonly occur in short span bridges and culverts which brings about hidden danger to traffic safety. Referring to this fact, with the help of FEM (finite element method) software ANSYS the “single plate bearing” of plate girder bridge is simulated numerically. Firstly the simulated model of the beam element is built, with which the transverse distribution of loads on plate girder bridge of different span is analyzed. According to the mechanical performance of the plate girder bridge and the cause leading to the “single plate bearing”, five strengthening schemes to delay or avoid the “single plate bearing” are proposed and the spatial models of solid element are built. The mechanical performances such as displacement, stress and so on are contrasted and analyzed. Furthermore the transverse stress of the hinged joint is analyzed in detail, and it is proposed that the adhesive strength between the new and old concrete should be applied to test the transverse stress at the hinged joint. At last according to the merit and demerit of the five strengthening schemes, the feasible schemes for the “single plate bearing” are given.