軸方向変形の拘束効果を考慮した鉄筋コンクリートはりの弾塑性性状に関する実験研究

抄録

A method exists for designing a building in which the form of collapse mechanism is assumed in advance. In sueh a case, it is recommended that the strength of columns of the structure be made higher than those of the beams. The rotation of the beam end is absorbed by the plastic deformation due to yielding of the reinforcing steel bars. The position of the neutral axis in the cross-sectional area can be seen to edge considerably near the compression zone crossing the central axis. As a result, the axial elongation can happen. If this condition occurs throughout the every span, the horizontal length of the building will expand as a whole. In considered to expand because of the slabs, possibly restraining the elongation in horizontal direction. Considering such a condition, the beam tending to yield is considered to be subject to the compressive forces from the surrounding structural members. Comparing the case where axial force was considered not to act on the beam, there is a potential that this compressive force will increase the flexural strength of beam so that the structure will not collapse in the assumed mechanism. In this study, the bending shear experiment of rectangular beam and T-shaped beam was performed to consider the effect of axial restriction of deformation, through a simple analysis. As a result, experiment and analysis show that the flexural strength of reinforced concrete beams increase by 50 % because of axial rigidity. This implies a potential that the structure will not collapse in the assumed mechanism.