An Evaluation of the Flexural Behaviour of Concrete-filled rectangular Flange Girders

Abstract

This paper presents a detailed study into the flexural behaviour of concrete filled rectangular flange girders (CFRFG's). These are steel beams in which the top flange plate is replaced with a concrete filled hollow steel section. A key advantage of these members is the increased torsional stability, which reduces the need for bracing under construction loading conditions. The tubular section can be any shape (e.g. circular, rectangular, and pentagonal) and the focus in the current paper is on simply supported girders with a rectangular section for the top flange, and stiffened webs. These are complex members and their behaviour is governed by several inter-related parameters which are studied herein. A nonlinear three-dimensional finite element model is developed and validated using available experimental data from the literature. A parametric study is then carried out focussing on the most salient properties such as web height, tubular flange dimensions as well as the width of the bottom flange. Finally, the paper presents a detailed discussion on the appropriate applications and design methods for these types of section, based on the results of the numerical analysis.