Analytical Model for Compressive Behavior of FRP-Confined Ultra-High Performance Concretes

Research on the compressive behavior of FRP-confined short columns has predominantly focused on conventional concrete. However, significant differences exist in the mechanical properties between Ultra-High Performance Concrete (UHPC) and conventional concrete. Consequently, directly applying analytical models developed for FRP-confined conventional concrete to UHPC structures may lead to substantial errors. To address this issue, this study established a comprehensive database and employed Grey Relational Analysis to identify the factors influencing the ultimate compressive strength of FRP-confined UHPC short columns. Based on the analytical results, a novel predictive model for estimating the ultimate strength of FRP-confined UHPC structures was developed, which significantly enhances computational accuracy. Furthermore, by evaluating and comparing existing constitutive models, the optimal constitutive relationships for UHPC short columns confined with either GFRP or CFRP wraps were identified.