【摘要】 以上海大歌剧院的露天悬挑楼梯为背景，对一根长15.04m的足尺缓黏结预应力悬挑梁进行预应力筋张拉测试，并对悬挑梁中3种不同长度的缓黏结预应力筋(RBPT)进行短期预应力损失和伸长值的研究。研究结果表明，张拉初始阶段RBPT的应力增长较小，之后应力与张拉力成线性增长的关系。RBPT单位长度中曲率效应造成的预应力损失比长度效应造成的预应力损失大。预应力损失中考虑黏滞力的影响后，得到本试验6℃下RBPT的摩阻系数κ,μ及黏滞系数ψ。按照规范JGJ 387—2017《缓黏结预应力混凝土结构技术规程》计算得到的RBPT有效预应力和伸长值比试验结果偏大，而根据本文考虑黏滞力后的计算公式和系数得到的计算结果与试验结果吻合较好，说明RBPT短期预应力损失和伸长值计算中需考虑黏滞力的作用，摩擦系数需根据实际张拉情况来确定。更多还原

【Abstract】 Based on the open-air cantilever staircase of Shanghai Grand Opera House, the prestressed tendon tension test of a full-scale retard-bonded prestressed cantilever beam with 15.04m length was carried out. The short-term prestress loss and elongation values of three different lengths of retard-bonded prestressed tendons(RBPT) in the cantilever beam were studied. The results show that the stress of RBPT increased small in the initial tension stage, and the relationship between stress and tension was linear after that. The prestress loss caused by curvature effect was larger than that caused by length effect in the unit length of RBPT. Considering the influence of viscous force, the friction coefficient κ, μ and the viscous coefficient ψ of RBPT at 6℃ were obtained. The results of effective prestress and elongation of RBPT calculated according to JGJ 387—2017 Technical specification for retard-bonded prestressed concrete structures are larger than the test results. However, the calculated results according to the calculation formula and the coefficients considering the viscous force in this paper are in good agreement with the test results, indicating that the viscous force must be considered in the short-term prestress loss and elongation calculation of RBPT. The specific values of the friction coefficients needs to be determined according to the actual tension situation.更多还原