部分预应力混凝土梁考虑裂缝闭合性能的裂缝控制设计方法的研究

Research on design methods of crack-controlling of partially prestressed concreted beams considering crack-closure

介绍了部分预应力混凝土梁的裂缝闭合性能,确定了裂缝闭合时梁底边缘名义压应力的大小;提出了卸载系数的概念,提出了基于卸载系数的部分预应力混凝土梁考虑裂缝闭合性能的适用条件和应用范围.参照《PPC建议》的混凝土裂缝控制方法,根据卸载系数的大小提出了新的考虑裂缝闭合时的裂缝控制设计方法.运用此方法不仅可以节约预应力筋的用量,而且在设计过程中可直接根据允许裂缝宽度的大小确定预应力的大小,克服了以往对裂缝只能被动验算的不足.

Crack-closure property of partially prestressed concrete(PPC) beams and nominal compression stress is introduced.The conception of unloading coefficient is presented first for PPC design.Then a new crack-controlling designing method is given according to the value of unloading coefficient.In the new design method,crack-closure property is considered.It is shown that with the new design method we can save prestressed steel and change the crack-controlling design method from passive checking computations to a...