Abstract
The purpose of this paper is to formulate the elastic strain concentration ratio and the plastic incremental strain concentration ratio of the beam flange at beam-to-column connections whose column cross section is H-shape. Elastic strain distributions and plastic strain distributions are considered to be independent, because the column has a heavy section and does not generate the plastic out-of-plane deflection. Let the elastic strain concentration ratio be denoted by β_e and the non-dimensional geometrical parameter of the beam-to-column connection be denoted by f[f=2T_<cf>^3/(3T_<bf>・B^2), T_<cf> : Thickness of the column flange, T_<bf> : Thickness of the beam flange, B : Breadth of the beam flange], then, the relation between β_e and 1/f can be expressed by hyperbola. In order to formulate the plastic strain concentration ratio, the plastic incremental strain concentration ratio and the non-dimensional parameter f_p[f_p=2 T_<cf>^3E/(3T_<bf>・B^2・H^'_m), E : Young's modulus, H_m^' : mean strain hardening ratio] are defined. The behavior of the plastic incremental strain concentration ratio is evaluated based on the results of the theoretical and experimental study. Consequently, it became clear that not only geometrical conditions but also material conditions and load hysteretic conditions have direct effects upon the plastic incremental strain concentration ratio, and these relations are formulated.
