Title:
Innovative Reinforced Concrete Deep Beam Analysis Using Improved Strut-and-Tie Method
Author(s):
Ali H. Alqarni, Hayder A. Rasheed, and Krishna Ghimire
Publication:
Structural Journal
Volume:
123
Issue:
3
Appears on pages(s):
211-224
Keywords:
deep beams; nonlinear response; reinforced concrete (RC) analysis; strut-and-tie method (STM)
DOI:
10.14359/51750571
Date:
5/1/2026
Abstract:
In this study, a detailed innovative procedure is devised to recover the full response of reinforced concrete deep beams using an improved strut-and-tie method based on ACI 318 rules. The load-deflection curve is described by two critical response levels represented by the yielding and ultimate points. The strut and tie method (STM) is used to determine the nodal displacements under a unit load and compute the yielding and ultimate load in the strut-and-tie model as the minimum force needed to realize each loading stage from all truss elements. Once the critical load at the two stages is determined, the elongation, strain, and stress of each element in the truss are extracted, thus avoiding the need to approximate the nonlinear strain profile across the depth. Also, two solution strategies using the secant and tangent stiffness are formulated, and their results are successfully compared to the experimental response of seven deep beams with a wide range of shear span-to-depth ratios. The failure modes reported experimentally perfectly match the failure member indicated by this improved analysis.
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