Gravity Load Collapse of Reinforced Concrete Columns with Brittle Failure Modes

Abstract

During the 1995 Kobe earthquake, dozens of concrete buildings suffered complete collapse at an interme-diate story. Such collapse is believed to have occurred due to the gravity load collapse following shear failure of Steel Reinforced Concrete (SRC) or Reinforced Concrete (RC) columns at a certain intermediate story. To study this collapse tests of RC column specimens were conducted. Test parameters were axial load and loading history. The tests have revealed that: 1) collapse occurs when shear force decreases to about zero, 2) axial load level is decisive for the collapse behavior, 3) loading history occasionally has a significant effect on the collapse behavior including a failure mode, and 4) a change in vertical deformation increment vs. lateral drift increment relations until collapse can be explained by the flow rule in plastic theory considering reduced failure surface.