Available theories of material behavior that predict size effect are receiving
increasing attention in the technical literature nowadays. Beam-column joint is one of
the vital elements, whose behaviour during earthquake is very critical. No study has
been done till today to establish the existence of size effect on beam-column joint.
Hence, in the present study, an experimental programme was taken by considering
flexure deficient beam-column joints. Three geometrically similar specimens were
considered as control specimens and three corresponding specimens were retrofitted by FRP. Cyclic loading system with a constant axial load on the beam column joint was applied during testing. The recorded data were plotted to draw hysteretic response, envelope curve, stiffness, energy dissipation etc. Comparisons of results were made between control and retrofitted specimens in term of all the above-mentioned properties and conclusions were drawn regarding the benefit derived out of retrofitting. Further, the percentage gain in capacity due to retrofitting and displacement ductility were tried to be correlated with size of specimens. To compare the energy dissipation of specimens having different sizes, a new parameter, viz. energy dissipation per unit volume ( eN ) was introduced for the first time in the context of evaluation of size effect. eN was correlated with the size of the specimen at different drift angles. Equivalent stresses for all the specimens were calculated and bi-logarithmic plots were drawn. It was observed that most of the properties follow principle of size effect. The most important finding is that- the bilogarithmic plot of unit strength follows the established law proposed by Baz?ant.