Experimental Evaluation of Friction Losses Between Post-tensioned Strands and Plastic Ducts

Abstract

Friction losses are short term losses in Post-Tensioned systems. The friction created at the interface of tendons and ducts during the stretching of a curved or straight tendon in a post-tensioned member leads to a drop in the prestress along the member from the stretching end. The purpose of this research is to study the friction losses between tendons and plastic ducts. Moreover, it has been shown that “corrugated steel ducts will fracture at cyclically opening cracks across the duct. Plastic ducts have been shown to perform better under similar conditions” [2]. This proves that plastic ducts are good ducts in durability and corrosion protection. Thus, the friction parameters for plastic ducts system will be evaluated in this research paper. The analysis results presented that the average wobble coefficient and the average curvature one for plastic ducts of 0.005/m and 0.1/rad, respectively, which are less than the values for steel ducts. Plastic ducts reduce the friction losses to 41% in comparison with the steel ducts at site work. In addition, plastic ducts reduce the friction losses to 33% in comparison with the steel ducts at laboratory work as presented in this paper. The values of (k) and (μ) for only metal sheathings, rigid metal ducts, and other types are introduced in PCI (Fig. 2)³. The primary goal of this research was to conduct an experimental evaluation of the friction losses between post-tensioned strands and plastic ducts. Moreover, in the (Fig. 14) below, the values of (k) and (μ) for only metal sheathings, rigid metal ducts, and other types are introduced [3]. In this research, the values for (k) and (μ) will be evaluated for plastic ducts in order to introduce values for (k) and (μ) for plastic ducts in the (Fig. 2).