engleski

The effect of the slenderness on the behavior of concrete cantilever columns under an earthquake

The paper presents the results of a shake-table study on the seismic behavior of 1/3 scale reinforced concrete columns with four different slenderness (λ = 50, λ = 70, λ = 100, λ = 125), i.e. with four different basic periods (T1 = 0.47 s, T1 = 0.64 s, T1 = 0.89 s, T1 = 1.05 s). Thereby, all columns have identical remaining properties (material, quantity and distribution of the reinforcement, foundation, mass at the top of columns, etc.). The tested columns were exposed to horizontal base accelerations of an artificial accelerogram, with successive increase of the maximum amplitude until the collapse of the columns or their severe damage. Characteristic displacements, accelerations and strains of the specimens were measured for each applied excitation. Some results of the research are presented and discussed. It was concluded that the slenderness of a column has quite significant effect on its seismic behavior and its ultimate bearing capacity, but far less than for static load. With the increase of the column’s slenderness, its bearing capacity is decreased and its displacements and strains (in both concrete and reinforcement) are increased. For example, the column with slenderness of λ = 125 collapsed under excitation with maximum ground acceleration of 4.0 ms-2, while the column with slenderness of λ = 50 collapsed under excitation with maximum ground acceleration of 5.0 ms-2.

Slenderness ; concrete cantilever column ; shake-table study

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