Transverse reinforcement effect on cracking behaviour of R.C. members

Abstract

Two extensive and independent experimental programs have been conducted to study the cracking behaviour of reinforced concrete members subjected to pure tension in the presence of transverse reinforcement. The first program involved the testing of eighteen reinforced concrete segments and was mainly designed to examine the applicability of the existing equations for predicting crack spacings and widths. The segments were reinforced in two directions and loaded in uniaxial tension beyond the yield stress of the steel. The measured average values of the final crack spacings were compared to the values presented by other researchers. Based on this comparison, a simplified and refined expression for prediction of crack spacing is proposed.The second experimental program involved the testing of sixteen reinforced concrete segments, which were divided into two groups with different concrete covers. Within each group, all segments were identical in all parameters, except the spacing of transverse reinforcement. The program was designed to study the influence of transverse reinforcement spacing on crack behaviour. A methodology including proposed expression for predicting the crack spacing in reinforced concrete members subjected to axial tension with variable transverse reinforcement spacing is presented. Keywords: cracking, crack spacing, crack width, membrane forces, reinforced concrete, tension, transverse reinforcement.

Reinforced Concrete Panels Subjected to Uniaxial and Biaxial Tension

“…6, a reinforced concrete member is subjected to an axial tensile force P. At the two cracks indicated, the steel carries all the tensile force at the stress designated as σ s0 . Stress concentration was noted at the intersection of two orthogonal bars due to the effect of the transverse bars (Rizkalla et al 1983). When the longitudinal bars in X-direction are stretched, the concrete surrounding the bars will resist the transverse bars.…”

“…Table 4 represents a comparison of the average crack spacing of thick plates, between Table 5 Measured and calculated average crack spacing for experimental program conducted by Rizkalla at al. (1983).…”

“…(1983). (Leonhardt 1977;Beeby 1972;and Rizkalla et al 1983). To enable an accurate crack spacing measurements to be obtained, the tested panels were carefully inspected at each load step.…”

“…This is to ensure the suitability of the proposed model for evaluating the value of the average crack spacing for various reinforced concrete members under different types of loading conditions. The previous experimental works involved direct tension tests carried out by (Rizkalla et al 1983) which are represented in Table 5, and laterally loaded slabs tested by (Hossin and Marzouk 2006) which are presented in Table 6.…”

“…Many research reports exist on the cracking behavior of reinforced concrete members. Rizkalla et al (1983; conducted an extensive study on the cracking behavior of reinforced concrete panels with compressive strength of 34.5 MPa and subjected to pure uniaxial tension in the presence of transverse reinforcement. Okamura et al (1987;2003) studied the bond and the tension stiffening of the cracked concrete, based on that investigation, a model to introduce the average tensile stress strain for concrete was developed.…”