Effects of the End-Zone Reinforcements and Strand-Debonding on the Temporal Changes of Principal Stresses at the Ends of the Hollow PC-Girders

Abstract

Hollow PC-girders are hollow along the length of the girder; because of this, the possibility of developing horizontal cracking at their ends at the prestressing time is high. In this paper, a numerical analysis was performed to examine the effects of strand-debonding and end-zone reinforcements on the principal stresses, which is the leading cause to develop horizontal cracks at the ends of the hollow PC-girders. First, the length of the selected PC-girder was reduced to 4 m span which is necessary for enough prestressing; after that, with the help of the Midas FEA software, a detailed prestressing analysis was conducted. This study indicated that debonding four PC-strands at the ends of the girder and placing end-zone reinforcements could decrease the magnitude of principal stresses to the level to be less than the tensile strength of concrete, and therefore, horizontal cracks were eliminated at the ends of the hollow PC-girder.