预应力混凝土受弯构件反向变形控制与验算

为解决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不完善的问题,结合工程实践,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.对于预应力混凝土板,以计算跨度、跨高比及控制截面预应力筋的位置为影响因素,计算得到了预应力混凝土板控制截面有效压应力限值.对于预应力混凝土梁,以计算跨度、跨高比及梁的负荷范围为影响因素,分析得到了梁控制截面有效压应力变化规律,并计算得到了预应力混凝土梁控制截面有效压应力限值计算公式.

Control and calculation for upward deformation of prestressed concrete flexural member

In order to solve the problem that the control of deflection for prestressed concrete flexural member is not perfect in the current standards and references at home and abroad,combined with the actual practice,the allowable upward deformation was presented after calculation.The influence factors on upward deformation of prestressed concrete flexural member was analyzed,and the method through limiting the effective compressive stress to indirectly control the upward deformation of prestressed concrete flexural member was discussed.For prestressed concrete slabs,the allowable value for the effective compressive stress in the critical section was presented with the following influence factors:span,ratio of span to depth of section and the location of prestressed steel.For prestressed concrete beam,the variability of the effective compressive stress in the critical section was presented with the following influence factors:span,ratio of span to depth of section and load-bearing range.In addition,the calculation formulas of the allowable values for the effective compressive stress in the critical section of prestressed concrete beam were obtained.