Detection of effective prestressing of 1860-grade strands based on the microporous method

Existing tensioning cable prestress ensures bridge safety. This work presents the micro-hole release technique, which accurately measures the effective prestress of strands in existing prestressed concrete bridges. The strand drilling model was produced in Solidworks and Abaqus. The effect of drilling depth, diameter, deflection angle, and hole edge distance on strand stress release was then examined. The findings indicate that strand drilling tension relief is directly related to hole depth and diameter. As aperture size increases, stress alleviation decreases. The stress release error rate increases as the strand drilling deflection angle increases from 0° to 15°. Portable electric drill bits are 1.5 mm. A 5.0 mm hole was bored into the steel wire. The steel strand drilling wire is 3.0 mm from the hole's edge. The drill bit is designed to maintain a drilling deflection angle of less than 5°, ensuring accuracy and ease of testing. After that, the 1860 grade strand drilling test was used to compare stress release and associated circumstances between P-T and T-P operating conditions. The strain-tension fitting equations for strand release were compared to finite element simulation results under P-T and T-P operating conditions. We found that the formula for fitting the strain-tension force of strand release under T-P condition matches finite element simulation results. It also matches real-world engineering methods.