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设计制作了12片先张法预应力混凝土构件,主要研究混凝土强度及钢绞线有效预应力对先张法钢绞线预应力传递长度的影响,通过测试钢绞线切断后预应力筋拉应变及混凝土表面压应变,分析其变化规律,并与现行JTG D62-2004《公路钢筋混凝土及预应力混凝土桥涵设计规范》及其他文献进行对比。结果表明:先张法钢绞线预应力传递长度随混凝土强度增加而减小,随钢绞线有效预应力增加而增大,按JTG D62-2004计算得到的传递长度偏于保守,依据试验结果得出的预应力传递长度可以很好地反映混凝土强度及钢绞线有效预应力对先张法钢绞线预应力传递长度的影响,建议公式计算值与实测值比值的平均值为1.01,标准差为0.02。
Twelve pre-tensioned prestressed concrete members are designed and manufactured. The effects of concrete strength and effective prestressing force on the pre-tensioned transfer length of pretensioned strand are studied. By testing the tensile stress of prestressing tendon and concrete Surface compressive strain, analyze its variation rule, and compare with the current JTG D62-2004 Code for Design of Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts and other documents. The results show that the prestressed transfer length of prestressed steel strand decreases with the increase of concrete strength and increases with the increase of effective prestressing force of steel strand, and the transfer length calculated according to JTG D62-2004 is somewhat conservative. Based on the test results Of the prestressed transmission length can well reflect the concrete strength and the effective prestressed steel strand pretensioned strand prestressed force transmission length, the proposed formula calculated value and the ratio of the average value of 1.01, the standard deviation of 0.02.