Verbundverhalten von vorgespannten Litzen in UHPC [Teil 1]

Bond Behavior of prestressed Strands in UHPC. Part 1: Tests on Bond Strength and Transfer Length

Ultra-High Performance Concrete (UHPC) is an appropriate construction material for pretensioned girders. To ensure an economic and safe design a detailed knowledge of the behavior of pretensioned strands in the anchorage zone is essential. The dimension of the bond anchorage zone favors the cost-effective design of pretensioned girders, especially when the shear resistance is decisive. However, a minimum concrete cover has to be maintained to avoid splitting cracks in the transmission zone, since they lead to an uncontrolled increase in transfer length and may cause a premature anchorage failure.
This paper, which resulted from the priority program SPP 1182 funded by the German Research Foundation, presents the results of investigations on the bond behavior of strands in UHPC. Part 1 deals with the experimental investigations and in part 2 a bond model is derived to design the transfer length.