重复荷载作用下部分预应力混凝土梁正截面的抗裂性

Resistance to Cracking of Normal Section in Partially Prestressed Concrete Beam Subjected to Repeated Loading

本文在回顾钢筋混凝土梁及全预应力混凝土梁正截面抗裂性计算的基础上指出以往的计算是针对承受以静力为主的构件,但对承受重复荷载为主的构件其正截面抗裂性计算应予以修正。文中根据对部分预应力混凝土梁在重复荷载作用下抗裂性试验结果和分析,以及混凝土材料抗拉疲劳强度的现有研究成果提出了重复荷载作用下部分预应力混凝土铁路桥梁混凝土抗拉疲劳强度的建议值及修正的抗裂性计算方法,并对部分预应力混凝土梁A、B类分类限值提出了新的建议。

The method of calculating the resistance to cracking of normal section in prestressed and reinforced concrete beams is reviewed in this paper.It is pointed out that in the old design code it considered only the effect of static loading and hence it must be modified when the beam is subjected to fatigue loading.The modified calculation method and the proposal of fatique tensile strength of concrete in partially prestressed concrete bridge beam is presented through the experimental and analytical results of resistance to cracking of partially prestressed concrete beams subjected to repeated loading and the achievements of research on concrete fatigue tensile strength.Moreover,the new boundary value between partially prestressed concrete class A and class B is proposed.