Title:
Minimum Transverse Reinforcement for Bottle-Shaped Struts
Author(s):
Oguzhan Bayrak and Michael Brown
Publication:
Structural Journal
Volume:
103
Issue:
6
Appears on pages(s):
813-822
Keywords:
reinforcement; shear; structural concrete; strut-and-tie modeling
DOI:
10.14359/18233
Date:
11/1/2006
Abstract:
Strut-and-tie modeling involves the use of struts to model the flow of compression within a concrete member. Bottle-shaped struts are wider at their midpoint than at either end. As the struts widen near the midpoint, tensile stresses transverse to the direction of compression are developed. Reinforcement must be placed within the strut to carry the transverse tension. This paper presents an equilibrium-based approach to determining the necessary amount of transverse reinforcement for a bottle-shaped strut. A database of 476 test specimens was then used to evaluate the equilibrium-based equations along with a series of three tests of deep beams. The strut efficiency factors presented in Appendix A of ACI 318-05 were used in this evaluation. Current ACI 318-05 provisions allow the design of a deep beam without any shear reinforcement; this issue is highlighted and its shortcomings are discussed.