ANALYSIS OF STRUCTURAL BEHAVIOR OF ROAD TEST RIGID PAVEMENTS

A CRITICAL REVIEW IS PRESENTED OF EXISTING THEORIES OF STRUCTURAL BEHAVIOR OF RIGID PAVEMENTS. THE THEORIES DIFFER PRINCIPALLY IN THE MODEL SELECTED TO REPRESENT THE SUBGRADE SUPPORTING THE PAVEMENT SLAB. TWO PRINCIPAL MODELS ARE BEING USED: (1) THE ELASTIC-ISOTROPIC SOLID, CHARACTERIZED BY A MODULUS OF DEFORMATION AND A POISSON'S RATIO, AND (2) THE WINKLER SUBGRADE, CHARACTERIZED BY A COEFFICIENT OF SUBGRADE REACTION. IT IS SHOWN THAT, WITH A SUITABLE SELECTION OF THE COEFFICIENT OF SUBGRADE REACTION, THEORIES BASED ON THE WINKLER MODEL FOR THE SUBGRADE CAN ALSO FURNISH ADEQUATE ANSWERS FOR SLABS RESTING ON A SUBGRADE BEHAVING AS AN ELASTIC-SOLID. EQUATIONS ARE PRESENTED TO CALCULATE THE SUBGRADE OF FINITE DEPTH. THE STRUCTURAL BEHAVIOR IS STUDIED OF RIGID PAVEMENTS OF THE AASHO ROAD TEST. IT IS SHOWN THAT THE OVERALL RESPONSE OF THE AASHO SUBGRADE TO LOADS IS COMPARABLE TO RESPONSE OF AN IDEAL ISOTROPIC-ELASTIC SOLID. HOWEVER, WITH PROPER SELECTION OF THE COEFFICIENTS OF SUBGRADE REACTION, THE WINKLER SUBGRADE MODEL CAN ALSO LEAD TO GOOD PREDICTIONS OF PAVEMENT STRESSES AND DEFLECTIONS. A MATHEMATICAL EQUATION IS DERIVED WHICH FURNISHES A RATIONAL BASIS FOR EVALUATION OF EQUIVALENCY OF SINGLE AND TANDEM LOADS UNDER MORE GENERAL CONDITIONS THAN POSSIBLE IN THE PAST.