空间曲线筋的摩擦和锚固预应力损失分析

Prestressing Losses due to Friction and Anchorage of Space-curved Tendons

根据现行规范GB5 0 0 1 0—2 0 0 2并参考有关资料,考虑建筑结构中空间曲线预应力筋的线形特点,给出其摩擦和锚固预应力损失沿程分布的计算公式和处理方法。方法将空间与平面曲线筋的预应力损失计算统一起来,且便于编程计算。通过工程实例说明该方法的应用。分析和实测结果表明:包角比弧长对摩擦损失的影响要大;当测试样本具有多样性时方可采用最小二乘法确定摩擦系数;采用综合法简化计算摩擦损失具有较好的计算精度;张拉端的预应力筋线形宜尽量平缓以减小预应力损失。

According to the GB50010—2002 code and relative references,the computing formulae and processing methods are proposed systematically for the analysis of prestressing losses due to friction and anchorage along the space-curved tendons,accounting for the characteristics of the prestressed tendons. The method given unifies the calculations of prestressing losses of space and plane curved tendons and is easy for programming calculations.The application of the method is illustrated with a practical example.The results of analysis and field test show that the subtended angle has greater influence on friction loss than length does; the least square method is utilized to determine the friction coefficients only if the test samples are diversified,it has higher accuracy for calculating friction losses with the synthetic method and the line shape of tendon in the tension end should be gentle in order to reduce prestressing losses.