Variability Analysis of the Hysteretic Behavior of Fiber-Reinforced Polymer (FRP)-Confined Concrete Columns Based on a Secondary Development Model

Abstract

A reasonable material hysteretic constitutive model has a significant influence on the seismic simulation results of structures. To better describe the hysteresis seismic performance of fiber-reinforced polymer (FRP)-constrained concrete, a new modified hysteresis constitutive model is proposed based on the existing model and with sufficient consideration of the drop section of the skeleton curve. The validity of the proposed model is verified by comparing with quasi-static experimental data of FRP-confined reinforced concrete (FRP-C RC) columns in the literature. Subsequently, the compressive strength of concrete is selected as a major variable, and a quasi-Monte Carlo method is utilized to generate random samples, which are substituted into the proposed modified model and some comparison models. Finally, the hysteretic behavior of FRP-C RC columns is analyzed from the perspective of the material strength variability. The results demonstrate that (1) The proposed hysteretic constitutive model is able to provide rational predictions of the hysteretic behavior of FRP-C RC columns, and the mean relative error of each specimen is less than 6%. It can be applied to carbon FRPs (CFRPs) and glass FRPs (GFRPs), as well as different cross-sectional forms such as cylindrical and square columns. (2) A large number of hysteretic behavior cases of FRP-C RC columns can be successfully analyzed from the perspective of concrete material variability combined with finite element software. The average and variation coefficient of the maximum horizontal force of FRP-C reinforced C30 concrete columns are 76.77 kN and 0.0488, respectively, while the average and variation coefficient of the maximum horizontal force of FRP-C reinforced C50 concrete columns are 91.14 kN and 0.0454, respectively. (3) The average value and variation coefficient of the maximum horizontal force and equivalent damping ratio of FRP-C RC columns are affected by the compressive strength, axial compression ratio and reinforcement ratio, which show a certain regularity.