Strength of short composite rectangular hollow section columns filled with lightweight aggregate concrete

This paper concentrates on the bond strength and axial capacity of concrete filled steel columns. A series of tests was performed to consider the behaviour of short composite columns under axial compressive loading, Two rectangular hollow steel sections (RHS) were used in these tests, namely 120×80×5 RHS and 150×100×5 RHS. The RHS sections were filled with normal and lightweight aggregate concrete where natural pouzzolan was used as the lightweight aggregate component in the latter concrete. The main objectives of these tests were to clarify the performance of the lightweight aggregate-concrete filled steel specimens compared with those manufactured from normal concrete. The experimental investigations included tests on short steel and short composite columns.The bond strength and the squash load in composite sections depend on several factors. The cross section and the length of the steel tube, and the type of concrete were considered in the present study.The experimental failure load is seen to be adversely affected when the height of the squash specimens is increased from 100 to 200 mm.The test results reported show that lightweight aggregate concrete offered higher bond strength than normal concrete, but the load–slip behaviour of all specimens is similar for both type of concretes, and the bond strength is not influenced by the section of tube steel specimens.Moreover the results of this investigation showed that the contribution of lightweight aggregate concrete to the squash load is shown to be considerable.