AN INSTRUMENT FOR DAMAGE ASSESSMENT OF REINFORCED CONCRETE STRUCTURES

QUITE RECENTLY, IT HAS BEEN SHOWN THAT THE IMPACT-ECHO (IE) METHOD CAN YIELD A GREAT DEAL OF INFORMATION ABOUT THE INTERNAL STRUCTURE OF CONCRETE, INCLUDING THE PRESENCE OF CRACKING AND DISBONDED REINFORCING MATERIAL. CAREFUL EXAMINATION OF THE IE METHOD, HOWEVER, SHOWS THAT UNDER MANY CIRCUMSTANCES IT CAN BE VERY DIFFICULT TO INVERT THE RESULTS IN ORDER TO OBTAIN QUANTITATIVE INFORMATION ABOUT THE INTERNAL STRUCTURE. MUCH OF THE AMBIGUITY IN ANY DATA INVERSION PROCEDURE CAN BE REMOVED BY PLACING ADDITIONAL CONSTRAINTS ON THE INVERSION. THIS PROPOSAL SEEKS SUPPORT TO PERFORM FINITE ELEMENT (FE) CALCULATIONS IN ORDER TO CALCULATE THE IE RESPONSE FOR SEVERAL MODEL STRUCTURES CONTAINING CRACKS AND DISBONDED REINFORCING MATERIAL. THESE RESULTS WILL THEN BE INVERTED USING NO A PRIORI KNOWLEDGE OF THE INTERNAL STRUCTURE OR THICKNESS. IN MANY CASES, THIS WILL LEAD TO A VERY POOR QUANTITATIVE INVERSION. INCORPORATING ADDITIONAL INFORMATION ABOUT THE STRUCTURE FROM OTHER NONDESTRUCTIVE MEASUREMENTS SUCH AS MAGNETIC, ELECTROMAGNETIC AND NUCLEAR METHODS WILL BE USED TO IMPROVE INVERSION OF IE RESPONSES.