非均匀接触压力分布条件下预应力摩阻损失研究

Research on prestress friction loss under non-uniformcontact pressure distribution

为探究桥梁预应力锚索在非均匀接触压力分布条件下的预应力摩阻损失情况,本文特以理论分析为依据,探讨了在非均匀接触压力条件下的预应力摩阻损失理论解析式,分别以弯曲角度和摩擦系数为自变量,结合数值模拟和工程实测数据对比分析。研究结果表明:1)预应力孔道弯曲角度越大,考虑非均匀接触压力的预应力摩阻损失增长速率越快,预应力束弯曲角度较小时,数值模拟结果更接近传统解析结果,弯曲角度较大时,模拟结果更接近考虑非均匀接触压力下的解析值;2)摩擦系数与预应力摩阻损失呈正相关,预应力弯曲角度较大时,考虑非均匀接触压力的解析式中,摩擦系数对摩阻损失的影响与有限元计算结果更为相近;3)工程实测数据结果显示,小角度弯曲钢束摩阻损失占总损失约52%,当钢束弯曲角度较大时,摩阻损失占据了所有损失的90%以上。本文研究结果可为桥梁工程中后张预应力技术的应用提供一定的借鉴与参考。

In order to explore the prestressed friction loss of bridge prestressed anchor cables under the condition of non-uniform contact pressure distribution,based on theoretical analysis,the theoretical analytical formula of prestress friction loss is discussed under non-uniform contact pressure conditions,the bending angle and friction coefficient are taken as independent variables,combined with numerical simulation and engineering measured data.The results show that:1)The larger the bending angle of the prestressed pore,the faster the growth rate of prestressed friction loss considering the non-uniform contact pressure,the numerical simulation results are closer to the traditional analytical results when the prestressed beam bending angle is small,and the simulation results are closer to the analytical values considering the non-uniform contact pressure when the bending angle is large.2)The friction coefficient is positively correlated with the prestressed friction loss,and when the prestressed bending angle is large,the influence of the friction coefficient on the friction loss is more similar to the finite element calculation result in the analytical formula considering the non-uniform contact pressure;3)The results of engineering measurement data show that the friction loss of small angle bending steel bundle accounts for about 52%of the total loss,and when the beam bending angle is large,the friction loss accounts for more than 90%of all losses.The results can provide a certain reference for application of mid-posterior tensioning prestressing technology in bridge engineering.