The shake-table study of the effect of longitudinal reinforcement ratio on the behavior of concrete cantilever columns

摘要

The results of the shake-table study on the effect of longitudinal reinforcement ratio on the behavior of concrete columns are shown. The small-scale (1:3) model of cantilever columns with mass at their top was exposed to horizontal acceleration of an artificial accelerogram. Acceleration amplitudes were successively increased until the collapse of the columns. Characteristic displacements and accelerations, as well as strains in the concrete and reinforcement were measured during the shake-table tests. It was concluded that the ultimate bearing capacity and deformability of a column significantly depend on the amount of its longitudinal reinforcement. By increasing the amount of longitudinal reinforcement, ultimate bearing capacity of the column is also increased, but not proportionally. The reason is greater stiffness of the column with higher amount of longitudinal reinforcement than of the column with low amount of longitudinal reinforcement, which generates greater seismic forces in it for the same excitation.