Estimating the service-level cracking behavior of deep beams

The objective of this study is to correlate the serviceability behavior of a deep beam, in terms of maximum crack width and total area of visible cracking, to the internal strain energy estimated from a representative strut-and-tie model. To accomplish this objective, the authors tested 12 deep beam specimens with a 10 x 20 in. (250 x 510 mm) cross section. Experimental variables included the shear span-depth ratio, quantity of vertical and horizontal web reinforcement, spacing of web reinforcement, and configuration of primary tension reinforcement. Based on the results, the authors provide recommendations for: 1) estimating the maximum diagonal crack width; 2) estimating the total area of visible cracking; and 3) optimizing the strut-and-tie model in terms of expected cracking behavior.