基于预应力效应的波形钢腹板曲线箱梁扭转应力分析

Analysis of torsional stress of curved box girder with corrugated steel webs considering prestress

为深入研究预应力效应对波形钢腹板曲线箱梁翘曲应力的影响,将预应力等效荷载应用到波形钢腹板曲线箱梁的计算中。通过乌曼斯基第二翘曲理论,根据波形钢腹板曲线箱梁的力学特性,建立了考虑预应力效应的波形钢腹板曲线箱梁的扭转微分方程,并采用初参数法求得约束扭转应力。研究结果表明:在非对称布置预应力钢束的情况下,将考虑预应力效应与不考虑预应力效应所引起的约束扭转应力进行对比,得到由预应力效应所引起的约束扭转正应力的比例达到33%,由预应力效应所引起的约束扭转剪应力的比例达到14.28%,由此可见在非对称布筋的情况下预应力效应产生的扭转效应不能忽视。将本研究的计算结果与有限元计算结果进行比较,吻合较好,表明本研究计算方法精度较高,可进一步完善波形钢腹板曲线箱梁桥的计算理论。

To study the effect of prestress on the warping stress of curved box girder with corrugated steel webs, prestressed equivalent load is applied to the calculation of curved box girder with corrugated steel webs. By Umansky’s second warping theory and the mechanical property of the curved box girder with the corrugated steel webs, the torsional differential equation of curved box girder with corrugated steel webs is established, and the constrained torsional stress is obtained by initial parameter method. The results show that prestressed effect is taken into account or not will lead to different constrained torsional stress if prestressed steel bundles are placed asymmetrically. The comparison shows that the ratio of the torsional normal stress caused by the prestressed effect reaches 33%, and that of the torsional shear stress is 14.28%.The torsional effect caused by the prestressed effect in the case of asymmetric reinforcement can’t be ignored. The calculation results of this paper are consistent with the finite element calculation results, which indicates that the analysis method has relatively high precision. The method can be used to improve the calculation theory of curved box girder bridge with corrugated steel webs.