Stress transfer characteristics of sheathed strand in prestressed concrete beams: Experimental study

Stress transfer of sheathed strand was examined using 24 small-scale prestressed concrete beams with bonded or sheathed strand. Variables included release method, sheathing material, and debonded length. Both debonding material and strand release method affect stress transfer. Sudden release increases transfer length due to the greater kinetic energy imparted to the beam. Transfer lengths in beams with rigid oversized sheathing were generally longer than in beams with flexible sheathing, an effect that is attributed to the existence of a nominal bond resistance mechanism due to dilation of the strand along the debonded length.