ABSTRACT
Mr Pritchard described his review of the techniques used to make precast prestressed beams continuous. H e favoured the use of wide in situ cross heads because they can accommodate deck plan and vertical curvature and avoid the use o f half-joints. Th e effects o f cree p and shrinkage balance out with time . M r Pritchard cite d th e case of a bridge under construction in Kuwait when th e beams being place d on th e pier head cause d i t to deflec t s o tha t collapse occurred . A questione r commente d that this system of construction was considered for Killikrankie Bridge; the stability of the pier top was investigated an d a possible solutio n was to use a n overhead gantry. I n the event thi s procedure was not adopted . I t was pointed ou t that it is necessary to consider the development o f cracking in the soffit concret e over the support. Hybri d beams, combining straigh t pretensioned tendons and ducted post-tensioned tendon s can be use d a s an alternative to draped pretensioned tendons .
