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New Strut-and-Tie-Models for Shear Strength Prediction and Design of RC Deep Beams

posted Aug 12, 2014, 12:33 AM by Domain Admin   [ updated Aug 12, 2014, 12:34 AM ]

A journal paper titled, “New Strut-and-Tie-Models for Shear Strength Prediction and Design of RC Deep Beams” was recently accepted for publication in Computers and Concrete (Vol. 13, No.7, 2014). Mr. Panatchai Chetchotisak (a PhD student at the Department of Civil Engineering, Khon Kaen University, Thailand), Prof. Jaruek Teerawong (Department of Civil Engineering, Khon Kaen University, Thailand), Dr. Sukit Yindeesuk (Department of Highways, Ministry of Transport, Thailand) and Prof. Junho Song at SSRG co-authored the paper.

This paper proposes a new Strut-and-Tie-Model (STM) for deterministic and probabilistic prediction of the shear strength of reinforced concrete deep beams, and develops corresponding limit-state design formula and reduction factors for a reliable design of reinforced concrete deep beams. A Bayesian parameter estimation method was used to reduce the bias and quantify uncertain errors of the proposed model based on a large database of experimental results. Seven different deterministic models which were selected from code of practices and literatures were compared with the proposed models. The abstract of the paper is given below.

Abstract : Reinforced concrete deep beams are structural beams with low shear span-to-depth ratio, and hence in which the strain distribution is significantly nonlinear and the conventional beam theory is not applicable. A strut-and-tie model is considered one of the most rational and simplest methods available for shear strength prediction and design of deep beams. The strut-and-tie model approach describes the shear failure of a deep beam using diagonal strut and truss mechanism: The diagonal strut mechanism represents compression stress fields that develop in the concrete web between diagonal cracks of the concrete while the truss mechanism accounts for the contributions of the horizontal and vertical web reinforcements. Based on a database of 406 experimental observations, this paper proposes a new strut-and-tie-model for accurate prediction of shear strength of reinforced concrete deep beams, and further improves the model by correcting the bias and quantifying the scatter using a Bayesian parameter estimation method. Seven existing deterministic models from design codes and the literature are compared with the proposed method. Finally, a limit-state design formula and the corresponding reduction factor are developed for the proposed strut-and-tie model.

One can download this paper as Author’s Accepted Manuscript Version from the following URL: https://dl.dropboxusercontent.com/u/4133487/Papers/Chetchotisak2014-AAM.pdf

The DOI number of the paper (permanent link) is: http://dx.doi.org/10.12989/cac.2014.13.7.000

(The full reference information of the paper will be updated at the Publications webpage.)

Strut-tie model for simply supported deep beam

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