Title:
Behavior of Deep Beams Containing High-Strength Longitudinal Reinforcement
Author(s):
Juan de Dios Garay-Moran and Adam S. Lubell
Publication:
Structural Journal
Volume:
113
Issue:
1
Appears on pages(s):
17-28
Keywords:
deep beams; high-strength reinforcement; one-way shear; reinforced concrete; safety; shear reinforcement; strut-and-tie
DOI:
10.14359/51687910
Date:
1/1/2016
Abstract:
Steel reinforcing bars conforming to ASTM A1035 have enhanced corrosion resistance and significantly higher tensile strength compared to conventional reinforcing steel grades. However, the impact of the unique stress-strain characteristics of this steel on the failure modes and strength prediction models is not yet fully understood. This paper reports on the laboratory testing to failure of eight large-scale specimens having small shear span to effective depth ratios and containing or omitting web reinforcement. All specimens were longitudinally reinforced with deformed A1035 steel bars with measured stresses at the peak load from 695 to 988 MPa (100 to 143 ksi)—significantly higher than the design stress limits defined in current codes of practice. Members without web reinforcement failed in a brittle manner after the formation of diagonal cracks joining the loads and supports. For members containing web reinforcement, the shear span to effective depth ratio and the longitudinal reinforcement ratio were both found to influence the failure mode and post-peak ductility. It was possible to develop designs that could exploit the high reinforcement strength while exhibiting acceptable serviceability characteristics and adequate ductility at failure. The safety of capacity predictions using ACI ITG-6R-10 provisions is presented.