Volume no :1, Issue no: 1, 2015

AN EXPERIMENTAL STUDY ON PERFORMANCE OF REINFORCED CONCRETE COLUMNS WITH STRUCTURAL DEFICIENCY

Author's: V. Zanjani Zadeh and S. Eshghi
Pages: [1] - [24]
Received Date: January 12, 2015; Revised January 28, 2015
Submitted by: S. Naganathan.
DOI: http://dx.doi.org/10.18642/sajcce_7100121440

Abstract

Cyclic performance of slender reinforced concrete (RC) columns with insufficient lap splice length enclosed by widely-spaced transverse bars with 90-degree hooks is studied in this paper. Four half-scale RC columns with 150mm square cross section and 1000mm height fixed in strong foundation were tested under reversed cyclic loading and different constant axial load levels. Three specimens were built accordance with ACI (pre-1971), and one specimen was built according to ACI (318-02) provision to serve as a benchmark. Plastic hinge method was also used to calculate flexural deflection of the columns. The results demonstrated that poorly confined short lap splices in the potential plastic hinge region of a slender column can result in significant reduction in ductility and strength. Hysteretic loops for the columns were unstable with rapid degradation of strength and pinching effect due to premature splice failure. High axial load resulted in considerable reduction in the ductility and energy dissipation capacity of the columns. In general, it seems the common mode of failure for the specimens was the bond deterioration of the spliced longitudinal reinforcements.

Keywords

reinforced concrete columns, lap splice length, hysteretic loop, ductility, strength.