TRANSFER OF LONGITUDINAL FORCE IN CRACKS IN NORMAL AND LIGHTWEIGHT CONCRETE

QUERKRAFTUEBERTRAGUNG IN RISSEN VON NORMAL- UND LEICHTBETON

IN MANY STRUCTURES IT IS POSSIBLE THAT CERTAIN CROSS SECTIONS ARE FIRST STRESSED BY BENDING AND THEN BY TORSION COMBINED WITH BENDING. IN ORDER TO GUARANTEE STABILITY TRANSVERSE FORCES MUST BE ABLE TO BE TRANSFERRED IN THESE CROSS SECTIONS. THIS IS PARTICULARLY THE CASE WITH INCLINED CABLE BRIDGES HAVING ONLY ONE CABLE PLANE IN THE LONGITUDINAL AXIS OF THE BRIDGE, WITH BRIDGES HAVING STANCHIONS ALONG THEIR LONGITUDINAL AXES (TORSIONAL MOMENTS ARE TAKEN UP AT THE ABUTMENTS), AND WITH TIEBACKS SUBJECTED TO TRANSVERSE STRESS, FOR EXAMPLE WALL-TYPE GIRDERS HAVING LARGE RECESSES IN THE TENSION AREA. SINCE THESE POINTS HAVE ONLY BEEN STUDIED IN A FEW TESTS ON NORMAL CONCRETE, AND NOT VERY SYSTEMATICALLY, IT IS INTENDED TO CARRY OUT MORE TESTS ON NORMAL AND LIGHTWEIGHT CONCRETE. THE AIM IS TO DETERMINE THE TRANVERSE FORCE WHICH CAN BE TRANSFERRED IN CRACKS WITH REFERENCE TO CONCRETE STRENGTH, CRACK WIDTH, AGGREGATE SIZE, NORMAL COMPRESSIVE STRESS IN THE CRACK, AND MUTUAL DISPLACEMENT OF THE SIDES OF THE CRACK.