体外预应力梁的摩擦单元与摩擦效应分析

Analysis on friction element and friction effect for external prestressed beams

构造了简单的体外预应力梁的摩擦单元,模拟转向块和体外筋之间的摩擦,同时指出了摩擦单元的位置。分析了不同偏心距和摩擦系数的体外预应力简支梁。计算结果表明:增加体外筋的偏心距是提高体外预应力梁承载能力的最有效手段,偏心距对预应力增量影响明显;摩擦的存在可减小梁的最大弯矩和挠度,增加预应力增量;当体外筋为无粘结筋时,可以忽略摩擦效应;当体外筋为未经润滑的钢绞线时,对于工程计算而言,忽略摩擦也是可行的。

A simple friction element of external prestressed beams was constructed,which simulated the friction between the external tendon and deviator.The location of the friction element was pointed out.The external prestressed simply supported beams with various eccentricities and friction coefficients were analyzed.The calculation results indicate that increasing the eccentricity is the most effective measure to enhance the load bearing capacity of external prestressed beams,and the influence of the eccentricity on the prestress increment is significant.The existence of friction reduces the maximum bending moment and the deflection of beams,and increases the prestress increment.For the unbounded tendon as external tendon,the friction effect can be neglected.For the strand without lubrication as external tendon,the neglect of friction is feasible in engineering calculation.