The use of Grade 300 prestressing strand in pretensioned, prestressed concrete beams.

The current editions of the American Association of State Highway and Transportation Officials' AASHTO LRFD Bridge Design Specifications and ACI 318-14 are based on years of experimental research and use the traditional 270 ksi (1860 MPa) prestressing strand. Recent developments have resulted in a higher-strength strand with an ultimate tensile strength of 300 ksi (2070 MPa). This paper presents the results of an experimental investigation looking at the behavior of pretensioned, prestressed concrete members containing 300 ksi prestressing strands. Eighteen T-beam test specimens were fabricated and used to evaluate the effects of using the higher-strength strand on transfer and development lengths as well as flexural capacity and ductility. The results from 35 transfer zones and 35 flexural tests are compared with a variety of known influential factors and the current code provisions for transfer and development length and nominal moment capacity. The results are also evaluated with respect to the tensile strength of the strand. [ABSTRACT FROM AUTHOR]