COMPARISON OF TIES CONFIGURATION FOR COLUMN UNDER COMPRESSIVE LOAD

Abstract

A tied column in the reinforced concrete structure is the one in which longitudinal bars are tied together with smaller diameter bars at intervals up the column. In Ethiopia most building in the seismic area have tied column. Ties should confine core concrete properly. One way to enhance confinement is using proper detailing, seismic hook. However, installation (bending) of confining reinforcement with a 135-degree hook (seismic hook) is not easy. Therefore, in practice, many construction workers in most part of our country with high seismic zones: Zone 3 and Zone 4 apply a confining reinforcement with a 90-degree hook (fixed by wire mesh) .But most of the building codes recommend using a 135-degree hook, especially in this seismic zones. In the present study, a comparison of two type of ties configuration by taking 150x150x465(mm) reinforced concrete specimens made. This study proposed two different type of ties configuration Introduced category 3 (IC3) and Introduced category 4 (IC4) and compared with 900 ties configuration under peak load and load-deformation behaviors. Three samples cast for each ties configurations having 8mm ties and three plain concrete with the same size. Additionally, two samples with similar geometry for 900 and 1350 compared having 6mm ties. Concentric axial compression load applied with the universal testing machine and average axial deformation were measured using linear voltage displacement transducer. The strain gauge was placed in ties at mid-height of the column. From observed experimental program ties with 900 configurations got the least performance for both diameter ties, its peak axial strength was 23.24% lower than seismic hook configuration for 8 mm ties. Introduced configuration 3 (IC3) was in good proximity with standard 1350 hook; axial peak load reduction of IC3 was 8.33% from 1350 hook. But IC4 result was similar to 900 ties configuration. In addition to experimental study analytical and nonlinear finite element model for 8mm formulated and the result was in good agreement with a standard hoo