Assessment of Shear Strength of Circular Reinforced Concrete Beams
About: This article is published in Aci Structural Journal.The article was published on 2016-11-01. It has received 2 citations till now. The article focuses on the topics: Shear strength & Cross section (physics).
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TL;DR: In this article, the collapse of the Wilkins Air Force Base depot building occurred without warning, and it is the discusser's understanding that some beams in the building were already being braced with shoring consisting of various wooden poles.
Abstract: It is not correct to state that the collapse of the Wilkins Air Force Base depot building occurred without warning. The structure was known to be extensively cracked in shear well before the collapse, and it is the discusser’s understanding that some beams in the building were already being braced with shoring consisting of various wooden poles. The observer was in fact looking for additional trouble at the time of the collapse, although it must be argued that the fact that the failure occurred while he was present was coincidence. The record of cracking for the particular design at Wilkins was so bad that a revised design had already been prepared and was used in some similar buildings. The January 1957 issue of the ACI Journal had several articles dealing with the failure and with the repairs to other structures of the same group that had not failed but that were showing significant shear cracking.
25 citations
TL;DR: In this paper , the authors proposed a simple analytical tool for the evaluation of the shear strength of reinforced concrete circular, solid or hollow, slender columns endowed with shear reinforcement and subjected to axial force, bending moment and shear force.
Abstract: The paper proposes a simple analytical tool for the evaluation of the shear strength of reinforced concrete circular, solid or hollow, slender columns endowed with shear reinforcement and subjected to axial force, bending moment and shear force. The proposed method considers the sole beam action by means of simplified stress fields and simultaneously satisfies the equilibrium under the above combined internal forces. The paper identifies basic points in the N-M-V ultimate interaction curve and describes the procedures for the evaluation of the internal forces of these points as well as the procedures for the evaluation of the internal forces of the points in between. The method is first applied to a set of circular solid columns with different geometric and mechanical properties and a comparison is drawn between the shear resistance resulting from the simplified method and that from a more complex non-linear mathematical programming problem proposed in the past by one of the authors. Then, to demonstrate the value of the method and define the field of its accurate application, the proposed method is applied to circular (solid or hollow) columns tested in laboratory by other researchers. Finally, the results of the proposed method are compared with those of some code formulations.
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01 Mar 1986
2,577 citations
TL;DR: In this article, a simple method is proposed whereby the strength enhancement provided by axial compression is separated from the concrete component of shear strength and considered to result from arch action.
Abstract: Aspects relating to the shear strength of circular and rectangular columns under seismic loading are presented An examination of existing design equations reveals wide differences in predicted responses Particular emphasis is placed on models capable of representing the interaction between flexural ductility and shear strength A simple method is proposed whereby the strength enhancement provided by axial compression is separated from the concrete component of shear strength and considered to result from arch action The strength of the concrete component is reduced as flexural displacement ductility increases Prediction of shear strength from the proposed and alternative methods are compared with results from a wide range of tests of columns failing in shear The proposed method is shown to provide significantly improved correlation with experimental results Conservative modifications are made to enable the method to be used for design
515 citations
TL;DR: In this paper, a truss model approach and related theories for the design of reinforced concrete members to resist shear are presented, as well as a model for the construction of deep beams, corbels, and other non-standar structures.
Abstract: Truss model approaches and related theories for the design of reinforced concrete members to resist shear are presented. Realistic models for the design of deep beams, corbels, and other nonstandar...
382 citations
TL;DR: In this article, an extensive experimental investigation aimed at evaluating the significant parameters that influence the magnitude of this size effect in shear was carried out and it was found that the reduction in sheer stress at failure was related more directly to the maximum spacing between the layers of longitudinal reinforcement rather than the overall member depth.
Abstract: The current American Concrete Institute (ACI) shear design procedures can be very unconservative if applied to large, lightly reinforced members because these procedures do not recognize that as the size of such members increases, the shear stress required to cause failure decreases. This paper describes an extensive experimental investigation aimed at evaluating the significant parameters that influence the magnitude of this size effect in shear. It was found that the reduction in shear stress at failure was related more directly to the maximum spacing between the layers of longitudinal reinforcement rather than the overall member depth. High-strength concrete members displayed a more significant size effect in shear than normal strength concrete members. Some simple modifications to the ACI shear design procedures are suggested that will result in a more consistent level of safety across the possible range of concrete strengths and member sizes.
307 citations
TL;DR: In this paper, a three component model for seismic shear strength of circular columns developed at the University of California, San Diego (UCSD) has been discussed to account for the effect of the concrete compression zone on the mobilization of the transverse steel.
Abstract: Because of its brittle nature, shear is regarded as a mode of failure that should be avoided in reinforced concrete bridge column design. To provide a reinforced concrete bridge column with sufficient shear strength, it is imperative that the shear strength be predicted in an accurate and dependable manner. This paper discusses revisions to the three component model for seismic shear strength of circular columns developed at the University of California, San Diego (UCSD). The revisions suggested account for the effect of the concrete compression zone on the mobilization of the transverse steel, as well as the effect of aspect ratio and longitudinal steel ratio on the strength of the concrete shear resisting mechanism. The proposed model is compared with the previous UCSD model, as well as the design approaches of the Applied Technology Council (ATC) Report 32 and Caltrans Memo 20-4 through the use of an experimental database consisting of 47 circular reinforced concrete bridge columns. For comparative purposes, the proposed model is also compared with the ATC-40 assessment approach. Results are presented in the form of the ratio of experimentally recorded strength to design strength versus various key design parameters.
201 citations