Cracking behavior and crack width predictions of FRP strengthened RC members under tension

Abstract

This is the accepted version of the paper.This version of the publication may differ from the final published version. Permanent repository link CRACKING BEHAVIOR AND CRACK WIDTH PREDICTIONS OF FRP STRENGTHENED RC MEMBERS UNDER TENSION AbstractThis paper presents and discusses the experimental results of uniaxial tensile tests of fiber reinforced polymer externally strengthened reinforced concrete (FRP strengthened RC) prisms in terms of crack width and crack spacing. As a non-contact and material independent system for in-time measurement of displacement and strain, the digital image correlation (DIC) technique has been used in this study for investigating the evolution of strains and formation of cracks during uniaxial tensile tests. As a result, the cracks were measured precisely at any load stage.The experimental results of tests performed by authors and other researchers on FRP strengthened RC members in tension are compared to prediction models from code provisions and guidelines (Eurocode 2 and fib 14), and their suitability are analyzed and discussed. The results show the dependence of the behavior and crack characteristics of FRP strengthened RC members to parameters such as wrapping scheme and FRP reinforcement ratios which are not included in design provisions for crack analysis. A new formulation for crack width and spacing for FRP strengthened RC members, calibrated using the experimental results, has been proposed which considers all the main affecting parameters.

Crack Width and Load-Carrying Capacity of RC Elements Strengthened with FRP

“…where the reduction factor ψ f is taken from (16), (17), (18), (19), (20), (21), and (22), only that A c ef f = b h − h cr u and I c ef f = b h − h cr u 3 /3. Real reduction coefficients of a concrete compressive zone stress diagram can be determined using the modified technique proposed by Dulinskas et al [29] (see Figure 6).…”

“…In accordance with design provisions [18,19], the cracks in concrete open when a limiting tensile strain of concrete is reached; therefore, the crack width can be calculated by multiplying the mean values of a difference between tensile reinforcement and concrete strains with crack spacing. The researchers working on cracking phenomena of FRP-strengthened structures are trying to correct the empirical formulas to calculate crack spacing given by the design norms [20][21][22]. A different approach is proposed in this paper, that is, a crack model for direct calculation of flexural crack parameters which neglect the crack spacing.…”

Development of Crack Width Prediction Models for RC Beam-Column Joint Subjected to Lateral Cyclic Loading Using Machine Learning

“…In the past decade, Artificial Neural Network (ANN) and Finite Element Modeling (FEM) have been extensively used to analyze and predict the formation and propagation of cracks [19][20][21][22][23]. Theriault and Mehdi developed a theoretical model for predicting crack width based on the effect of Fiber Reinforced Polymer (FRP) numbers and thickness against the reinforcement ratio in concrete beams and prisms [24,25]. In other research, the mechanism of softened truss theory and bonding deterioration was proposed and developed using ANN and numerical modeling to estimate the crack width among reinforced concrete elements [26,27].…”

Crack parameters in normal section of FRP strengthened RC elements

“…But to use all the potential of this material, external reinforcement should deform up to 1.6%, in this case high plastic deformations will occur in the element. In accordance with design provisions (EN 1992(EN -1-1:2004Fib bulletin 14, 2001) the cracks in concrete open when a limiting tensile strain of concrete is reached, therefore crack width can be calculated by multiplying the mean values of a difference between tensile reinforcement and concrete strains with crack spacing, what works quite well in elastic stage and there are various researches conducted on improving design standards in elastic stage (Ceroni & Pecce 2007, 2009Zomorodian, Yang, Belarbi, & Ayoub, 2016). A different approach is proposed in this paper, i.e.…”