Title: Elongation Tolerance for Short Tendons in Post-Tensioned Building Structures
Author(s): Carol Hayek and Thomas H.-K. Kang
Publication: Structural Journal
Appears on pages(s): 795-802
Keywords: bonded; elongation; measurement; post-tensioned building structures; short tendons; tolerance; unbonded
Elongations have been used to assess the forces inside post tensioned tendons immediately after the post-tensioning operation. However, the measured elongations are characterized by a high degree of uncertainty and variability due to site tolerances, and that the calculated elongations are based on the ideal equations using theoretical parameters. Building codes acknowledge such variability as a limitation and include tolerances for the elongation deviations between the calculated and measured values. Even so, the specified tolerances are quite stringent and unrealistic for relatively short tendons. In this study, to resolve this issue, a statistical analysis is carried out using a large database of tendon elongations measured from actual projects of bonded post tensioned building structures. Based on the analysis of the data collected, a practical and rational tolerance between measured and calculated elongations is proposed.