鋼構造柱梁接合部の歪集中に関する実験的研究 (その 2)

Abstract

The purpose of the paper is to investigate the effect of the out of plane stiffness of the column flange on the strain concentration of beam-to-column connections in steel structures under increasing alternative loading. The test specimens are H-TYPE (the shape of the column cross section is H), and are small-scale ones. They are manufactured by machineworks from the rolled steel plate (thickness; 65 mm, SS 41). The specimens are made so as to represent the part of the beam flange without stiffening plates. The increasing alternative load is subjected to the end of the beam flange. Strain and displacement in the plastic region of the beam flange are calculated by MOIRE analysis. The characteristics of the strain concentration of beam-to-column connections are influenced considerably by the characteristics of the plastic out of plane deflection of the column flange. In regard to the beam flange of beam-to-column connections which did not generate the plastic out of plane deflection of the column flange, summary of the results are shown below. (1) The amplitude of the strain at the end of the joint is larger than the amplitude of the strain at the middle of the joint. (2) In regard to the strain distribution from which subtract the initial residual strain at every loop, the reversal of the strain concentration occurs. (3) When the stress surpasses the past largest range, the strain concentration ratio increases rapidly. (4) Mean stress-mean strain relations at the beam flange near the joint to the column flange are almost equal to material stress-strain relations. (5) Elastic strain distribution and plastic strain distribution are almost independent. These distributions are approximated by parabola. (6) The elastic strain concentration ratios are constant.