Flexural Behaviour of Concrete Beams with High Strength Reinforcement

Sohaib Akbar, The University of Western Ontario

Abstract

Using High Strength Reinforcement (HSR) in concrete construction allows steel volumes to be reduced, and economies to be realized. CSA Standard A23.3:19 “Design of Concrete Structures” limits the maximum yield strength for design to 500 MPa. This thesis investigates the flexural behavior of concrete beams reinforced with HSR to assess whether current code provisions are appropriate. Curvature ductility ratios are calculated for cross-sections with varying concrete compressive strengths, and reinforcement types and quantities. The effects of utilizing HSR on extreme fibre concrete compressive strains at Ultimate Limit State (ULS), moment redistribution at ULS, and deflections at Serviceability Limit States, are investigated. It was found that curvature ductility factors for sections reinforced with HSR are relatively less; A23.3:19 Clause 9.2.4, which specifies the maximum permissible moment redistribution at ULS, is appropriate for all beams investigated; and designs that meet the minimum height requirements of A23.3:19 Table 9.2 satisfy the deflection limits in A23.3:19 Table 9.3 for all beams investigated.