Crack-Based Shear Strength Assessment of Reinforced Concrete Members Using a Fixed-Crack Continuum Modeling Approach

Abstract

With the inventory of aging and deteriorating concrete infrastructure continuing to grow throughout much of North America and other regions of the world, there is a need for cost-effective tools that can provide meaningful assessments regarding structural damage. This paper presents a crack-based analysis procedure that can be used to estimate the residual shear strength of cracked reinforced concrete beam-type elements, based on a member-idealized, fixed-crack-continuum analysis procedure. Easy-to-obtain concrete crack measurements, which serve as input, are used in combination with basic material mechanical properties, member geometry and detailing, and cracked concrete dedicated behavioral modeling to provide estimates of the residual/remaining member shear capacity and to forecast critical shear crack widths to be referenced in future inspection and monitoring efforts. The fixed-crack continuum modeling approach is presented in a manner that can accommodate transverse confining stresses stemming from disturbed regions and relevant to the analysis of reinforced concrete beams. Two different procedure solution methods were investigated: one employing an assumption regarding the longitudinal stress acting on the idealized element and one using an estimate of average longitudinal strain based on known loading proportions. Data pertaining to 48 different beam specimens, comprising five different experimental programs documented in the literature, were employed for validation. The results presented in this paper demonstrate that even with the use of easy-to-obtain crack data and simple cracked-concrete modeling techniques, crack-based assessment procedures can be used to provide meaningful structural performance assessment data for existing concrete infrastructure.