Test Error Sensitivity for Methods of Testing Prestressed Friction Loss

Although numerous studies have been conducted on prestressed duct friction loss test methods, only a few have considered the error sensitivities of the test methods used. For this paper, to conduct a prestressed duct friction loss test, the test error sensitivity coefficients of strain distribution and tension force ratio methods were derived. The effects of prestressed tendon parameters on the error sensitivity coefficient were studied and validated through a statistical analysis involving large amounts of in situ test data. The results indicated that the tension force ratio method was sensitive to test error, especially when the difference in tendon angle was less than 3° and the length was less than 15 m. The test error sensitivity coefficient of k was greater than that of μ under the same conditions. To compensate for the shortcomings of the strain distribution and tension force ratio methods, the P-Δ method was proposed and a solution for the P-Δ method was derived. A comparative analysis indicated that the error sensitivity of the P-Δ method used to calculate the curvature friction coefficient μ was significantly less than that of the tension force ratio method, while test error amplification also occurred when the P-Δ method was used to calculate the wobble friction coefficient k.