ABSTRACT
Experimental methods are described which are being used to investigate the behaviour of bonded tendons suddenly released during demolition of post-tensioned concrete structures. Results from simplified drop tests have indicated the need for a more realistic simulation of the movement of large prestressing tendons cut during demolition. As a result, cutting tests in which bonded prestressing strands and bars cast in concrete beam models are suddenly released have subsequently been undertaken. Laboratory work in this difficult area must be limited to idealised scale models which are less than satisfactory for simulating the actual behaviour in real structures. However, important information about the complex mechanics of dynamic debonding of large tendons is being obtained before attempting more realistic field trials.
