Preventing Brittle Failure of Tension Splices in High-Strength Concrete

Abstract

Safety concerns and a lack of test data on bond capacity of deformed reinforcing bars embedded in high-strength concrete are among the reasons for the ACI 318 building code imposing an arbitrary limitation of 10,000 psi (69 MPa) when calculating tension development and splice lengths. This limitation was first introduced in the 1989 revision of the ACI 318 building code. In an attempt to evaluate the impact of this limitation and develop provisions for its removal, an investigation was carried out at the University of Nebraska-Lincoln, partial result of which will be presented in this paper. Results of the investigation are used to discuss the differences that exist between normal and high strength concrete, develop hypotheses to explain these observed differences, and suggest alternatives for removal of the current concrete compressive limitations existing in the ACI 318 building code for calculating tension development and splice lengths. In this paper high strength concrete is defined as concrete with compressive strength exceeding 10,000 psi (60 MPa).