Investigation of Influence of Section Pre-crack on Shear Strength and Shear Resistance Mechanism of RC Beams by Experiment and 3-D RBSM Analysis

Abstract

In order to investigate the influence of crack through section, which is often generated under cyclic loading, on the shear behavior and strength of RC beam, an experimental method was attempted to introduce a 0.5 mm and 1.0 mm-wide pre-crack, respectively, in beam cross section. The two pre-cracked beams were tested and the shear behaviors were compared with a non-cracked one. As the experimental result, it was found that the section pre-cracks led to a significant degradation of shear strength. Secondly, the different shear behaviors between pre-cracked and non-cracked beams were simulated by 3-D RBSM, and the developments of shear resistances were decomposed into the shear contributions provided by beam action and arch action. Based on the decomposition result, it became clear that the arch actions governed the grades of shear strengths and the section pre-cracks played a primary role in inducing extra crack behaviors and obstructing the longitudinal compressive stress transfer in concrete.

Analytical Study on the Effect of Different Shear Reinforcement Shapes on Shear Failure Behavior and Shear Resistance Mechanism of RC Beams

“…The analytical method used in this study is 3-D RBSM (Yamamoto et al 2008), which enables to directly express discontinuous behaviors of concrete, such as cracking and fracturing. It has been verified by several studies that this method can reproduce the crack propagation and shear failure behavior of RC members with good accuracy (Yamamoto et al 2010(Yamamoto et al , 2014Gedik et al 2012;Fu et al 2017Fu et al , 2020Nakamura et al 2018).…”

“…It is known that the shear resistance mechanism of an RC member consists of beam and arch actions (Park et al 1975), and that these can be decoupled using analytical results obtained by 3D-RBSM (Fu et al 2017(Fu et al , 2020Nakamura et al 2018).…”

“…There are study cases in which these shear resistance mechanisms have been decoupled from the results of loading tests on RC beam specimens using reinforcement strain measurements (Kim et al 1999;Nakamura et al 2006;Yamada 2019;Gunawan et al 2020). On the other hand, it is possible to evaluate these mechanisms directly using numerical methods that allow visualization of stresses at specific positions (Fu et al 2017(Fu et al , 2020Nakamura et al 2018;Yamada 2019). Nakamura et al (2018) discussed the shear resistance mechanism of RC beams with shear reinforcements using a three-dimensional rigid-body spring model (3-D RBSM) (Yamamoto et al 2008), showing that it can evaluate the shear failure behavior of RC members with high accuracy.…”

Numerical Evaluation of Shear Strength Degradation Mechanism Dependent on the Size Increase of RC Deep Beams with Height up to 1.5 Meter by Using 3D Rigid-Body-Spring-Method

“…The method was applied to simulate various structural performances of concrete members, such as flexural and shear behaviors of beam, column and wall members. It succeeded in representing not only load-displacement relationships, but also localized cracking behavior (Gedik et al 2011(Gedik et al , 2012Yamamoto et al 2014;Fu et al 2017aFu et al , 2017b. The brief outline of the 3D RBSM is described in this section.…”

The Effect of Inner Friction on Concrete Fracture Behavior under Biaxial Compression: A 3D Mesostructure Study

“…The second issue is to calculate the built up model, and many methods have been adopted, such as traditional finite element method [18,19], the lattice model [20,21,22], the homogeneous model (such as meso-element equivalent method) [23,24,25], the extended finite element method [26,27], and the scaled boundary finite element method [28,29,30]. The discrete element methods are also considered, such as the particle flow method [31,32,33] and the rigid-body-spring method [34,35].…”