81 research outputs found
Visualization of Shear Cracks in a Reinforced Concrete Beam using the Digital Image Correlation
A low-cost digital image correlation system is used to visualize the formation and propagation of concrete cracking in a reinforced concrete beam. The system employed comprises an ordinary digital camera, a remote image recording controller (a smartphone) and a freely-available, open-source image correlation software package Ncorr. In this paper, the application of this system is demonstrated to obtain a comprehensive time-lapse of longitudinal strain fields developing before and after the onset of shear cracking, thus allowing one to fully appreciate the mechanisms of shear failure in the beam. It is shown that the longitudinal strain fields obtained from the DIC system are in a good agreement with hand-drawn crack maps and that obtained from nonlinear finite element analysis
Visualization of shear cracks in a reinforced concrete beam using the digital image correlation
Sectional Analysis of Engineered Cementitious Composite Beams
A procedure to predict the flexural response of an engineered cementitious composite (ECC) prismatic beam specimen subjected to four-point bending and its implementation into an Excel spreadsheet are described. It utilises the layered sectional analysis approach and nonlinear ECC constitutive models, allowing for the calculation of the moment–curvature relationship for any selected section of the beam specimen at various stages of loading. Further, the curvature–area method is employed to integrate the sectional response and determine the overall beam deflection profile. To this end, predictions by the proposed method are compared against three series of experiments available in the literature, to provide a better understanding of the relation between the tensile properties of ECC and the corresponding flexural response. It is shown that due to flexural cracking, the beam curvature over the shear span varies nonlinearly from the support and is found to influence the prediction of beam deflection. A series of empirical equations are presented to allow for the quick calculation of tensile strain capacity and tensile strength of ECC based upon flexural test data. </jats:p
Performance assessment of reinforced concrete after long-term exposure to a marine environment
Application of Nonlinear Finite Element Analysis on Shear-Critical Reinforced Concrete Beams
This paper presents the application of a smeared fixed crack approach for nonlinear finite element analysis of shear-critical reinforced concrete beams. The experimental data was adopted from tests undertaken on twelve reinforced concrete beams by Bresler and Scordelis in 1963, and from duplicate tests undertaken by Vecchio and Shim in 2004. To this end, all beams were modeled in 3D using the software package ATENA-GiD. In the modeling, the nonlinear behaviors of the concrete were represented by fracture-plastic constitutive models, which were formulated within the smeared crack and crack/crush band approaches. The applicability of nonlinear analysis was demonstrated through accurate simulations of the full load-deflection responses, underlying mechanisms, crack patterns, and failure modes of all 24 beams. Detailed documentation of the results is presented to demonstrate the potential and practical value of nonlinear finite element analysis in providing an informed assessment of the safety and performance of reinforced concrete structures
Enhancing the out-of-plane performance of masonry walls using engineered cementitious composite
In-situ dynamic WetSEM imaging and electrical impedance measurements on Portland cement during early hydration
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