高温差地区预应力混凝土箱形梁日照温度应力分析

Analysis of temperature stress forpre-stressed concrete box girder in high temperature difference area

阐述了预应力混凝土箱形桥梁温度应力产生的原因,依据箱型桥梁的温度边界特点,给出了高温差地区箱形桥梁日照温差分布形式,并将箱身温度应力按沿板厚非线性温差自约束应力和箱身横向约束应力来考虑。通过对奎北铁路线桥梁的计算表明:在高温差地区,温差变化作用下混凝土箱形桥梁桥身外表面将产生较大的横向温度应力,会导致桥身混凝土出现纵向裂缝,应通过施加横向干预,提高梁体的抗裂性能。

This paper introduces the cause of temperature stress in pre-stressed concrete box girders,andputs forward the distribution form of temperature stress according to the beam’s temperature border characteristics.Moreover,the transverse thermal stress is divided into two parts,i.e.nonlinear self-restraint stress of temperature difference within theslab thickness and restrictive thermal stress of the transverse frame.The calculation about the bridge in Kuibei railway line shows that：in high temperature difference area,big transverse temperature stress will be produced on the surface of the bridge under the effect of temperature variation and longitudinal cracks will be created,Therefore,the anti-cracking performance of the concrete can be improved through the application of the transverse pre-stress therein.