IMPACT FACTORS FOR SIMPLE CONCRETE BRIDGES

THE DYNAMIC DEFLEXIONS RECORDED ON 22 SPANS OF TEN DIFFERENT CONCRETE BRIDGES SUPPORTING A MOVING TRUCK ARE REPORTED AND THE MAXIMUM DISPLACEMENTS ARE COMPARED WITH PREDICTIONS BASED ON A SIMPLE MATHEMATICAL MODEL IN WHICH THE BRIDGE IS IDEALIZED AS A SINGLE SIMPLY SUPPORTED BEAM AND THE VEHICLE IS REPRESENTED BY A SINGLE AXLE SPRUNG LOAD. FOR MOST OF THE SPANS TESTED THE DYNAMIC IMPACT ALLOWANCE IMPLIED BY CURRENT CODE PROVISIONS IS SHOWN TO BE INADEQUATE. A MORE SATISFACTORY BASIS IS PROPOSED FOR THE DETERMINATION OF DESIGN IMPACT FACTORS FOR SIMPLE CONCRETE BRIDGES. /AUTHOR/