Effect of Development and Geometry on Behavior of Concrete Deep Beams

The effect of development type and length and beam geometry on the behavior of discontinuity regions in concrete deep beams was investigated through experimental testing and numerical study. Observations of cracking patterns and measurements of load and displacement at midspan of four large-scale concrete deep beams tested under a three-point load setup were used to calibrate numerical models. Thirty-five specimens were then modeled in a nonlinear finite element software to evaluate the strength of deep beams with different development lengths, development types, strut angles, and beam geometries. Development length and type of development was found to impact the presence of tensile stress in the support nodes. A rectangular beam geometry was found to cause diagonal tension stresses in the struts, not present in truss-like specimens. The tensile stresses from reinforcement development and diagonal tension were found to not be additive in these rectangular beams. Keywords: deep beam; development; failure mechanism; finite element; strut-and-tie.