Three one fourth scale models using ultra high-strength concrete(f' =704 kg/㎠) are tested under the combined action of a constant axial and a horizontal load cyclically to failure. Such specimens are considered to represent the critical 3-story of l...
Three one fourth scale models using ultra high-strength concrete(f' =704 kg/㎠) are tested under the combined action of a constant axial and a horizontal load cyclically to failure. Such specimens are considered to represent the critical 3-story of low part in 60-story tall building of a structural wall system in area of high seismicity. The amount of vertical reinforcement and the level of applied axial stress are identical for the three wall tested. The cross-section of all walls is barbell shape. The aspect ratio(h /l ) of test specimen is 1.8. The primary objectives of this paper are to investigate the influence of the amount of horizontal reinforcement on the lateral resistance, failure mechanism, ductility and energy-dissipation capability of walls with ultra high-strength concrete.
In contrast to what is widely believed, the horizontal web reinforcement does not appear to have a significant effect on shear capacity. Certainly, since the reduction of the web horizontal reinforcement to almost half the value specified by building codes doesn't affect the failure load, this effect in not accounted for by the truss analogy concept. The results obtained have helped to identify the causes of wall failure and have demonstrated that the concepts underlying current ACI Building Code provisions for the design of walls conflict with the observed structural behavior. It has been found that shear resistance is associated with triaxial compressive stress conditions that develop in the compressive zone of the section at the base of the wall.