The transfer and development lengths of prestressing strands are critical parameters in the design of precast, pretensioned concrete members because they have a direct impact on both the flexural and shear designcapacities of the members. However, because of the extreme difficulty and time required to experimentally determine these quantities, designers must currently assume values for the transfer and development lengths.Designers have historically assumed that the values provided in the American Concrete Institute’s Building Code Requirements for Structural Concrete (ACI 318-08) and Commentary (ACI 318R-08) and the American Association of State Highway and Transportation Officials�? AASHTO LRFD Bridge Design Specifications are applicable and conservative for pretensioned members. This is a different approach from that used for many other reinforced concrete design properties, such as concrete compressive strength, density, and air content. These properties are routinely measured, and their design assumptions verified, for the components used to construct prestressed concrete members. Due to the continual increase in complexity of concrete mixture proportions as new mineral and chemical admixtures are employed, it is critical to verify the ability of strands to bond to the surroundingconcrete. In 2004, a program was initiated to evaluate the bond between self-consolidating concrete (SCC) and prestressing steel in pretensioned concrete members. This paper focuses on the development of a simple test thatprecasters can use to verify bond between their concretes (both SCC and conventional) and the pretensioned steel reinforcement. The purpose of the simple test is to provide the precaster with a tool to evaluate prestressing steel bond at the plant without going through lengthy and costly research programs. This test will serve as a quality assurance test for precasters to verify the bond performance of their mixtures. It is envisioned that it will also assist producers in the evaluation of new admixtures, mixture proportions, and process changes.
