ALL POSSIBLE CHANGES IN THE MODES OF FAILURE, AS A RESULT OF VARIATIONS IN THE MODULUS OF ELASTICITY OF THE FRP MATERIAL (WHILE KEEPING ITS ASSOCIATED ULTIMATE TENSILE STRENGTH, FOR A GIVEN BEAM DESIGN, CONSTANT), IN EXTERNALLY PLATED R.C. BEAMS, HAVE BEEN ADDRESSED IN SOME DETAIL, WITH A QUANTITATIVE TREATMENT OF THE CRITICAL VALUES OF THE FRP MODULUS OF ELASTICITY ASSOCIATED WITH VARIOUS FAILURE MODE TRANSITIONS (I.E. CHANGES).