MEASUREMENT OF INTERNAL STRESSES BY MEANS OF THE RELEASE METHOD

MESURE DE CONTRAINTES INTERNES PAR LA METHODE DE LIBERATION

TO DEVELOP A METHOD OF MEASURING INTERNAL STRESSES IN CONCRETE OR METAL STRUCTURES. IN CONCRETE THE METHOD CONSISTS OF DIGGING A CHANNEL AND USING AN ULTRA-FLAT JACK TO RE-ESTABLISH THE INITIAL FIELD; IN METAL AN INSERT INSTRUMENTED WITH STRAIN GAUGES IS RELEASED OR A HOLE IS PIERCED IN THE IMMEDIATE VICINITY OF THE GAUGES. IN 1979 IT IS ENVISAGED: - TO MONITOR AND STUDY THREE CONCRETE SLABS; - TO PREPARE THE MANUFACTURE OF A CONCRETE BOX GIRDER WHICH WILL BE SUBJECTED TO COMPOUND FLEXURE; - TO CARRY OUT TESTS ON A PRESTRESSED CONCRETE SECTION SIMULATING THE BEHAVIOUR OF REAL STRUCTURES; - TO CONTINUE THE STUDY OF THE POST-OPERATIVE REPAIR OF THE CHANNELS; - TO EXTEND THE RESEARCH TO METAL STRUCTURES.