A study was conducted at Kansas State University to determine the correlation between tensioned-wire pullout tests and the corresponding transfer lengths in prestressed concrete railroad ties. Five different 5.32-mm-diameter pre-stressing wires were selected to be used on this project based on previous testing conducted at Kansas State University (KSU). The wires were tested to simulate the transfer-length bond.
The transfer-length bond test involved tensioning each of the wires to 75% of their ultimate capacity, casting concrete around each wire and then de-tensioning the wire when the concrete had reached 4,500 psi. End-slip and force measurements were recorded on both sides of the specimen as the wire was de-tensioned.
Transfer bond data was used to investigate the transfer length that each wire type would expect to see in a concrete railroad tie. Prisms with each wire type were cast and the transfer length was measured for each type of wire. Prism measurements were used along with the transfer bond data to correlate a relation between the transfer bond test and the transfer lengths of the prisms.