SHEAR STRENGTH OF REINFORCED CONCRETE COLUMNS WITH LOW WEB REINFORCEMENT CONSIDERING COMPRESSIVE STRUT SHAPE

Previous research shows the prediction of the shear capacity of column, with low web reinforcement ratios, based on truss and arch mechanism provided by AIJ gives underestimate strengths when consider axial load. In this study, experimental tests were conducted to evaluate the effect of axial force on ultimate shear strength calculated based on arch and truss mechanisms concept having specimens with low web reinforcement. From the experimental tests, the following conclusions were obtained: 1) the angle and width of compressive strut decrease and increase with an increase of axial load, respectively; 2) the estimation of column shear capacity including an increase of axial force was determined by modifying the shape of compressive strut; 3) the recent formula shows a good agreement with previous research results by using proposed factor of effectiveness concrete compressive strength; 4) the shear strength contributed from truss mechanism was not influenced by an increasing of axial load.