Size effect in shear failure of longitudinally reinforced beams

The aims of this research were to develop a simple method for the design of fiber-reinforced polymer (FRP)-reinforced beams and to determine if a common approach for steel and FRP-reinforced members is possible. A model is presented for calculating the concrete contribution to shear strength of reinforced concrete beams. The applicability of the model is supported by comparing the computed shear strengths with the experimental strengths of 370 specimens. The shear strength equation developed from the model is simplified to yield a design equation applicable for both steel and FRP-reinforced beams. The design equation is demonstrated to provide conservative results across the range of variables known to affect shear strength.

Concrete shear strength: another perspective

Predicting the shear strength of reinforced concrete beams using artificial neural networks

This paper presents a review of research on shear strength of reinforced concrete members without stirrups (shear reinforcement). A database of 1849 available experimental results from over the past 60 years is examined and these results are compared to predictions from current North American shear design procedures. Special attention is paid to the behavior of beams ranging from short span deep beams to members controlled by flexure. The findings from the review indicate that using the current ACI shear provisions to decide where shear reinforcement is required can be unconservative for members with larger effective depths, or higher stresses in the longitudinal reinforcement. Improvements to the ACI Code are proposed to mitigate these weaknesses. The AASHTO-LRFD and Canadian CSA sectional and strut-and-tie provisions are found to provide a more uniform level of safety for all member types. The results from this review can allow engineers to identify members in their own structure where a more conservative shear design procedure is appropriate.

Where is Shear Reinforcement Required? Review of Research Results and Design Procedures

Despite the abundance of research works, both experimental and theoretical, conducted since the middle of the previous century up to today, the determination of the shear stress value is still remains an open issue of great interest in structural engineering. The need for further research is indicated by the fact that the majority of available proposals, whether proposed by regulatory agencies or various individuals researchers, lead to the estimation of different shear stress values; moreover, the comparison of estimated values with experimental values demonstrates that the available proposals lead to an overestimation or to an underestimation of the “true” shear stress. In this research study, the artificial neural networks approach is used to estimate the ultimate shear capacity of reinforced concrete beams with transverse reinforcement. More specifically, artificial neural network models have been examined for predicting the shear capacity of concrete beams, based on experimental test results available in the pertinent literature. The comparison of the consequent results with the corresponding experimental ones as well as with available formulas from previous research studies or code provisions makes obvious the ability of artificial neural networks to evaluate the shear capacity of reinforced concrete beams in a trustworthy and effective manner. Furthermore, the preliminary results presented in this work reveal the crucial parameters that affect the value of the shear strength of reinforced concrete beams with or without transverse reinforcement.

Soft computing-based techniques for concrete beams shear strength

AN EXTENSIVE TEST PROGRAM FOR THE INVESTIGATION OF THE SHEAR RESISTANCE OF REINFORCED CONCRETE BEAMS WAS CARRIED OUT. SIXTY-THREE T, I, AND RECTANGULAR BEAMS WITH VARYING CROSS SECTION, WEB REINFORCEMENT, LONGITUDINAL REINFORCEMENT, CONCRETE STRENGTH, AND SHEAR SPAN WERE TESTED. STUDY OF THESE AND OTHER RESULTS LEAD TO THE CLASSIFICATION OF SHEAR FAILURES INTO FOUR BASIC MODES. THESE MODES ARE DESCRIBED AND EQUATIONS DEVELOPED FOR THE CALCULATION OF COLLAPSE LOADS FOR FAILURES BY DIAGONAL TENSION, SHEARING, SHEAR COMPRESSION, AND WEB CRUSHING. THE ULTIMATE LOAD IN A GIVEN CASE IS INTRINSIC TO THE FAILURE MODE CORRESPONDING TO THE LEAST STRENGHT AFTER DIAGONAL CRACKING. A FORMULA FOR CALCULATING SHEAR CRACK WIDTHS IS PRESENTED. /AUTHOR/

Shear failure of reinforced concrete beams

Synopsis The four major modes of shear failure—diagonal tension, shearing, shear-compression and web crushing—are discussed briefly and equations are given for predicting resistances to them. The larger part of the paper is devoted to two other design criteria. An analytical approach to shear cracking at vertical web-flange junctions is outlined and its predictions are compared with the results of a limited group of tests by the authors. A semi-empirical equation is derived for the calculation of limit state of local damage resistance as determined by widths of shear cracks, and is compared with more extensive test data for various types of beam tested by the authors and others.

A. L. L. Baker

Papers

Shear failure of reinforced concrete beams

Limit-state design for shear in rectangular and T beams