预应力次梁楼盖边梁抗扭设计

Torsion-resistant design of side beams in floors with prestressed secondary beams

采用等效荷载法计算次梁中的预应力在边梁中产生的次扭矩,当预应力筋线形布置对称时,根据固端弯矩相等的原则,用换算均布荷载对次梁中预应力筋等效荷载进行简化,近似计算边梁的次扭矩.推导了常见线形时换算均布荷载的计算公式.通过工程实例分析,介绍了考虑边梁次扭矩作用的边梁抗扭设计过程,并对设计结果进行了对比分析.结果表明:考虑次扭矩后,边梁扭矩设计值约减少了20%.

The secondary torque of side beams caused by the pre-stress in secondary beams was calculated using the equivalent load method. When the reinforcement layout was symmetrical, the equivalent load in the pre-stressed secondary beams could be simplified by the transformed uniformly distributed load according to the principles of equivalent bending moments at fixed ends. Accordingly, the secondary torque of the side beams was approximately calculated. The formulas of the transformed uniformly distributed load for usual reinforcement layout were deduced. Through an engineering case, the process of torsion-resistant design of the side beams was introduced. The calculated results were compared and analyzed. The analysis indicates that the design value of the torque decreases by about 20% when the secondary torque of the side beams is considered.