Tension-Stiffening Effect Consideration for Modeling Deflection of Cracked Reinforced UHPC Beams

Le Teng,Rongling Zhang,Kamal Henri Khayat

doi:10.3390/su14010415

Abstract

Tension-stiffening effects can significantly influence the flexural performance of cracked reinforced concrete specimens. Such effect is amplified for fiber-reinforced concrete, given the fact that fibers can bridge the cracks. The objective of this study was to develop a model to predict the deflection of cracked reinforced ultra-high performance concrete (R-UHPC) beam elements. The modeling approach characterized the average bending moment of inertia by combining the existing model used for conventional reinforced concrete and the analytical model of stress distribution of UHPC along the cross-section. The finite element analysis (FEA) was employed to evaluate the flexural deflection based on the average bending moment of inertia. The calculated load-deflection relationships have been compared to experimental results. The results indicated that the relative errors of deflection between predicted and experimental results can be controlled within 15%, compared to values ranging from 5% to 50% calculated by neglecting the tensile properties of cracked UHPC and values ranging from 5% to 30% calculated by effective inertia of bending moment of ACI code. Therefore, the developed model can be used in practice because it can secure the accuracy of deflection prediction of the R-UHPC beams. Such a simplified model also has higher sustainability compared to FEA using solid elements since it is easier and time-saving to be established and calculated.

Highlights

Conventional concrete (CC) has a high risk of cracking without a large deformation, resulting in a relatively low structural resiliency and environmental sustainability.For example, the major earthquake or impact loading can lead to fracture failure of CC structures [1,2]
The results in this study show that neglecting the tensile stress of non-cracked concrete in the finite element model (FEM) model can lead to 50% higher deflection compared to the experimental results [21]
This study aims to develop a model to calculate the average inertia of bending moment of cracked reinforced ultra-high performance concrete (R-Ultra-high-performance concrete (UHPC)) beams with the consideration of the tension-stiffening effect

Summary

Introduction

Conventional concrete (CC) has a high risk of cracking without a large deformation, resulting in a relatively low structural resiliency and environmental sustainability.For example, the major earthquake or impact loading (i.e., vehicle collision) can lead to fracture failure of CC structures [1,2]. Conventional concrete (CC) has a high risk of cracking without a large deformation, resulting in a relatively low structural resiliency and environmental sustainability. The presence of cracks reduces the durability of concrete and reinforcing steel. Ultra-high-performance concrete (UHPC) is regarded as a sustainable cementitious composite compared to conventional concrete [3,4]. This is due to the optimized packing density, and low water-to-binder ratio can secure dense microstructure to resist the intrusion of aggressive ions [5,6,7]. The use of steel fibers can restrain the cracking opening and propagation [8]

Objectives

Methods

Results

Conclusion