PERFORMANCE EVALUATION OF U-BLOCK LINTEL BEAM ELEMENTS USING FRACTURE MECHANICS

The strength of block masonry depends upon the strength of blocks and cement mortar. The strength of any materials inherently related to small flaws which are invariably present in all structures. This fact is very important in case of block masonry. Till now it is seen that fracture mechanics theory has not been applied to the block masonry, in India and abroad. Therefore in the current study which includes the small flaws in blocks, cement mortar and block masonry is initiated. The propagation of crack is governed by the stress intensity factor K1c which indicates the ability of a material to resist crack propagation. Therefore in the present study an effort has been to investigate Mode-1 critical stress intensity factors of block masonry with the critical stress intensity factors of block and cement mortar by using laws of mixtures which already exists in the theory of composites. Among the different specimens adopted such as centre cracked specimen, single edge crack specimen, double edge cracked specimen, the most common one has the single edge notched beams in either three point bending or four point bending. For this investigation experiments were conducted on blocks, cement mortar and block masonry beams under both three point and four point bending. Findings: Applications/Improvement: The same kind of study can be extended to at least different grades of concrete which will help in obtaining a trend of the variation of fracture energy with compressive strength. The load carrying capacity of a lintel can be determine by using different diameter of bars within the minimum and maximum reinforcement as recommended by IS 456-2000[1]. Fracture energy can also be determined using the other available methods recommended by RILEM and compared with the fictitious crack model.