The effects of tie hook angle on structural behavior of reinforced concrete columns

Because of the fact that one of the most important features of reinforced concrete structures is ductility, structural elements of a building must satisfy the rules of design codes. By not satisfying the design rules such as diameters, spacing, tie hook angle, it would not be provided efficient lateral confinement by transverse reinforcements. Hence structure cannot behave as expected in case of earthquake. However, the purpose of this study is to investigate the effect of tie hook angle on the behavior of axial loaded reinforced concrete columns depending on concrete compressive strength and tie spacing. For this purpose, axial loading tests were carried out on reinforced concrete short columns with hook angle of 90° and 135°. A comparative study in terms of fracture behavior, strength and ductility was done after obtaining load-displacement curves both experimentally and analytically. After studies, it is seen that tie hook angle and tie spacing play a very important role in the fracture behavior of axial loaded reinforced concrete columns. In the case of excessive tie spacing, it was observed that columns fail due to longitudinal bar buckling without hook openning when tie hook angle is 135° where in case of tie hook angle is 90°, columns fail due to bar buckling after hook openning.