Statistical prediction of post-tensioning system relaxation based on the in-service surveillance

Abstract

The purpose of this paper is to present and establish a procedure to predict the prestress forces during the service life of the system. The statistical approach of this procedure is using the in-service surveillance data of the post-tensioning system to develop a regression analysis. The regression analysis results can be used to check the prestress force at the end of the service life so that the remaining prestress force is equal to or exceeds the design requirement. Results from the surveillance program of a nuclear power plant containment structure were used to demonstrate the procedures.