BEHAVIOUR OF HIGH-STRENGTH FffiER REINFORCED CONCRETE COLUMNS SUBJECTED TO CONCENTRIC AND ECCENTRIC AXIAL LOADS

Abstract

High-Strength Concrete is a brittle material and also the increase in concrete strength reduces its ductility. The higher the strength of concrete, the lower is its

ductility. This inverse relations between strength and ductility is a serious drawback for the use of high-strength concrete, and compromise between these two characteristics of concrete can be obtained by adding discontinuous fibers. The behavior of high-strength concrete columns confined by rectilinear ties, and subjected

to different loading conditions was investigated. I

An experimental program consists of two phases was carried out. The llrst phase included tests of sixteen square specimens under axial loads only. Effect of variables such as concrete compressive strength, amount of transverse reinforcement. yield strength of transverse reinforcement, column height. spacing of transverse reinforcement, amount of fiber content and fiber types ,,•as inYestigated. The second phase included tests of six square columns I subjected to both axial loads and eccentric loads. The main variables were the concrete compressive strength, amount of fiber content, and the applied

cccentricitv. Moreover. the mechanical properties of fiber high-strength concrete using two types of fibers. and two concept of adding silica fume; one hy using silica fume amount as a replacement of cement content, the second concept is using silica fume by addition to cement content, are investigated.

I This study includes also the effect of each parameter on the strength, stiffness

II