预应力水平拉杆作用效应增量的计算

根据瑞利—李滋法,对先张法预应力吊车梁首次提出了预应力水平拉杆作用效应增量的计算公式.效应增量对吊车梁是有利的,可以提高预应力的利用率,从而提高吊车梁的承载能力.利用本公式确定水平拉杆作用效应增量,不仅可避免直接将最大拉应力作为初始预应力造成的危险,而且降低了施加初始预应力的难度.算例表明,所提出的公式具有简洁明了、适用性强、计算精确度高的特点.

A calculation method of action effect increment of prestressed horizontal tension rod

Base on Rayleigh-Ritz method, a calculation formulation of action effect increment of a prestressed horizontal tension rod is firstly presented. The action effect increment is advantageous for the crane girder. It may enhance the utilization ratio of prestress and the bearing capacity of the crane girder. If the initial pretension is calculated from the formulation, not only the danger of misterpreting the maximum stress as the initial prestress can be avoided, but also the difficulty of putting pretension on the prestressed horizontal tension rod can be reduced. The numerical example shows that this is a succinct method with wide applicability and high accuracy.