Influence of Casting Position on Development and Splice Length of Reinforcing Bars

摘要

The objective of this study was to reexamine the development and splice length requirements for top cast bars based on a comparison of stresses developed at ultimate rather than at a specified value of loaded end slip. To understand the historical development of design provisions for the influence of casting position, an extensive survey of the literature was undertaken. An experimental investigation of the magnitude of bond strength reduction as a function of the location and orientation of the reinforcement and the properties (slump) of the fresh concrete was undertaken. Specimens were designed and constructed with bars cast at different heights above the bottom of the form and oriented horizontally or vertically. The bond strength of each of these bars was compared to that of a bottom bar at ultimate.