Journal Article

Effects of Web Thickness and Flange Thickness on Flexural Crack Evolution and Ductility of H-Shaped UHPC Piles Based on DIC and Finite Element Analysis

Xie, Qinghai, Feng, Xiaotian, Qu, Peiliang, An, Guoqing, Zhang, Dashuai, Meng, Jinxin, Zong, Zhongling

2026

Overview

This study aims to reveal the control mechanism of key geometric parameters (flange thickness and flange edge thickness) of H-shaped cross-section on the bending performance of UHPC piles. Through conducting bending tests, combined with digital image correlation (DIC) technology and finite element simulation, the mechanical behavior was studied, and based on the principal strain field obtained from DIC, a strain field concentration index was proposed. The results show that: as the load ratio increases, the strain field concentration and the peak value of the mid-span principal strain continuously increase, and the crack evolution changes from dispersed development to localized control; near the limit state, the strain field concentration can reach approximately 0.28, and the peak value of the principal strain increases in an increasing trend, approximately 20% or more. Under the specific conditions of this test, in terms of ductility and energy absorption, when the flange thickness is constant, increasing the flange thickness of the web increases the energy absorption of the component by approximately 6% to 10%, while the ductility coefficient decreases by approximately 9% to 15%; when the web thickness is constant, increasing the flange thickness reduces the ductility coefficient by approximately 21% to 25%, and the energy absorption decreases by approximately 27% to 29%. The strain field concentration can effectively reflect the evolution process of the localization of bending cracks in H-shaped UHPC piles and can be used for quantitative analysis of their ductility degradation and energy absorption characteristics. It should be clarified that this study does not claim to isolate the effect of a single parameter.

• Publisher: MDPI AG
• Subject: Concrete / Corrosion / crack localization / Crack propagation / digital image correlation (DIC) / Ductility / ductility and energy absorption characteristics / Ductility tests / Energy absorption / Evolution / Finite element method / Flanges / Influence / Limit states / Load / Localization / Mathematical models / Mechanical properties / Optimization / Parameters / Propagation / Reinforced concrete / Simulation / Strain / strain field localization index / Stress concentration / Tensile strength / Thickness / ultra-high performance concrete (UHPC) / web and flange thickness