预应力混凝土结构钢绞线有效应力测量与评估方法

The effective stress of steel strand in prestressed concrete structure is a key factor that determines the bearing capacity and safety of prestressed structures. To measure the effective stress of the steel strand in prestressed concrete structure, a method which involves the measurement of the unloading slant axial strain with an additional correction factor K was proposed. The loading and unloading tensile tests of steel strands at the stress level of 0.32-0.74 were conducted. Based on the test results, the relationship on effective stress wtih unloading axial strain and slant axial strain was proposed. The test results show that, the error of the steel strand stress calculated based on the axial strain is large. The calculated stress values of the steel strand matched well with the measured slant axial strain multiplied by the correction factor. Based on the test results, the value of the correction factor K of the slant axial strain was determined to be 1.1.