CONCRETE BRACKETS STRESSED BY SHEAR AND TORSION

BETONKONSOLEN: AUF ABSCHEREN UND TORSION BEANSPRUCHT

IN BUILDING WITH REINFORCED CONCRETE PRECAST ELEMENTS IT OFTEN HAPPENS THAT EDGE GIRDERS AND SUPPORTING BRACKETS ARE USED WHICH ONLY HAVE TO SUPPORT LOADS ON ONE SIDE. WHEN THESE GIRDERS ARE INSTALLED THEY MUST BE RESISTANT TO TORSION TO PREVENT OVERTURNING. THEY CAUSED ADDITIONAL TORSIONAL STRESS ON THE BRACKET. ACCEPTED DESIGN RULES ARE NOT ADEQUATE FOR COPING WITH THIS TYPE OF STRESS. IF WITHIN THE BRACKET THE TORSIONAL MOMENT IS SEPARATED INTO A PAIR OF FORCES WITH THE PURPOSE OF DESIGNING FOR EACH OF THE FORCES IN THE USUAL MANNER, COMPATIBILITY IS NOT GUARANTEED. THERE IS A DANGER OF PREMATURE CRACKING. THE OBJECT OF THE PLANNED TESTS IS TO STUDY THE BEHAVIOUR OF BRACKETS UNDER THIS TYPE OF LOADING IN ORDER TO OBTAIN A BASIS FOR SENSIBLE DESIGN.