预应力混凝土受弯构件反向变形控制与验算方法

目前，国内外有关标准和文献对预应力混凝土受弯构件的变形控制对象都是总变形值，按照这一规定，常常出现这样一种现象：外载引起的变形很大，反拱值也很大，但总变形值满足规范要求，此时构件使用功能不佳。针对这一问题，我们经过试算，提出了反向变形限值。对预应力混凝土受弯构件反向变形影响因素进行了分析，对采用限制有效压应力来间接控制预应力混凝土受弯构件反向变形的方法进行了探讨，提出了预应力混凝土受弯构件控制截面有效压应力的限值建议。

Control and Calculation Methods for Upward Deformation of Prestressed Concrete Flexural Member

At present, in the standards and references at home and abroad, the total deformation of prestressed concrete flexural member is limited. According to this provision, a phenomenon often occurs: the deformation due to the external load is very bigger, and the upward camber is bigger also, but the total deformation meets the requirements. In this case, the member is not good in service. In consideration of this problem, the allowable upward deformation is presented after calculation. The influence factors on upward deformation of prestressed concrete flexural member is analyzed, and the method through limiting the effective compressive stress to indirectly control the upward deformation of prestressed concrete flexural member is discussed. The allowable values for the effective compressive stress in the critical section of prestressed concrete flexural member are proposed.