Effects of Friction Loss Due to Elongation of Prestressing Strands in Prestressed Concrete Slabs with Different Stand Arrangements: A Case Study of a Large Building Construction Project

Abstract

Friction losses due to prestressing strand elongation are a significant concern in prestressed concrete flooring systems, especially in large-scale or high-rise buildings that utilize post-tensioned concrete systems. The losses of friction may result from different arrangements of prestressing strands, therefore affecting the long-term performance and safety of building structures. This research study aims to examine the impact of friction losses caused by elongations of prestressing strands arranged in different arrangements. Compare the different values between calculated theoretical values with actual reading values at the project site, and compare these different values with the values noted in the ACI 318–19 requirements for building work by selecting a large building construction project that utilizes post-tensioned concrete flooring systems, with 17different alignments of prestressing strands. Each alignment of prestressing tendons will calculate friction losses due to the elongation of prestressing strands, following the guidelines of the ACI 423.10R-16 standard. Compare friction losses and prestressing strand elongations from values calculated theoretically and actual reading values measured on-site. The research findings demonstrate that arrangements of prestressing strands with horizontal deviations result in losses of friction due to the elongation of the prestressing strands, which are greater than in strand arrangements without deviations. The arrangements of long prestressing strands will have higher friction losses due to the elongations of the prestressing strands compared to arrangements with shorter prestressing strands. The elongation values of prestressing strands in different strand layouts indicate that differences between actual readings and theoretical values are lower than values specified in ACI 318-19 standard. Consequently, the proper configuration of prestressing strands will reduce friction losses resulting from the elongation of prestressing strands for prestressed concrete floor structures to be effective for long-term performance.