Prediction of shear strength of reinforced concrete beams without shear reinforcement considering bond action of longitudinal reinforcements

Abstract

The shear strength of concrete beams without shear reinforcement is determined by the shear strength of the concrete compressive zone, the shear force due to dowel action, and the shear force due to aggregate interlock. The existing models and formulas to predict shear strength of concrete beams based on geometric theories related to beam action and arch action that only consider shear resistance in relation to arch action while neglecting dowel action and aggregate interlock have been unable to accurately explain the shear resistance mechanism. This study proposes a more rational shear strength prediction formula that reflects the contribution of each component by linking the bond characteristics of longitudinal reinforcements based on the size effect and stress changes in longitudinal reinforcement to dowel action. The precision of the proposed formula was assessed by carrying out experiments with the shear-span-to-depth ratio (a/d = 2.0, 2.5, 3.0, and 4.0) as a variable. A ratio of shear bond failure distance to effective depth and the shear strength of concrete beams without shear reinforcement were compared to those obtained from the proposed prediction formula. As a result, it was confirmed that the proposed formula gives rational predictions for each shear contribution and exhibits a high accuracy compared to previous experimental results.

Analysis of Dowel Action in Reinforced Concrete Beams with Shear Reinforcement

“…3) Contribution V a, was 17 % -24 %, V cz was 50 % -55 % which was in agreement with [12]. Hence it can be concluded that empirical formula holds good in determining the shear resistance of beams with transverse reinforcement provided.…”

“…Further [12] had determined that effect of aggregate interlock was 15 % -25 % and dowel force was 20 % -27 % by keeping a'/d ratio constant and proposed an empirical formula as mentioned in Eqs. ( 2) and (3) to evaluate various components in shear strength.…”

Experimental Evaluation on Components of Shear resistance of Reinforced Concrete Beams with Shear Reinforcement Provided

“…Further " Kim et al (2018)", had concluded that aggregate interlock effect was 15%-25% and dowel force was 20%-27% by keeping shear span to depth ratio constant and proposed an empirical formula to evaluate various components in shear strength.…”

Probabilistic studies on mechanics‐based shear capacity models for reinforced concrete beams with stirrups

“…More than one mechanism is generally involved and the contribution of each in resisting shear has to be deciphered . The investigations on RC beams without stirrups are being carried out till date because failure of such beams is more brittle than RC beams with stirrups. However, in engineering practice shear reinforcement is usually provided in beams and so it is more relevant to investigate on shear behavior of RC beams with shear reinforcement.…”