Title:
Empirical Modeling of Reinforced Concrete Shear Strength Size Effect for Members without Stirrups
Author(s):
Evan C. Bentz
Publication:
Structural Journal
Volume:
102
Issue:
2
Appears on pages(s):
232-241
Keywords:
shear strength; size effect; stirrup
DOI:
10.14359/14274
Date:
3/1/2005
Abstract:
The reduction in shear stress at shear failure as member depth of beams and slabs not containing stirrups increases is known as the size effect in shear. While many theoretical models for this phenomenon have been proposed over the years, this paper provides a purely empirical study of the effect. Twenty-four different size effect series of shear experiments are examined, and curve fit parameters are calculated for three different equation formats. Equations to estimate the curve fit parameters are presented that may be useful in generating design specifications that include size effect. The conclusions include that a size effect equation based on a power equation is not as good as a 1/d-based equation with a depth offset. Aggregate size and longitudinal percentage of reinforcement were found to be important in the estimation of shear strength. No strong evidence was found that size effect data for shear in reinforced concrete beams without stirrups should be modeled with effective depth to the power of –0.5 as would be expected from linear elastic fracture mechanics.