Closure to “Effective Flange Width Definition for Steel–Concrete Composite Bridge Girder” by Methee Chiewanichakorn, Amjad J. Aref, Stuart S. Chen, and Il-Sang Ahn

Abstract

This closure article was written in response to a commentary on recent research (Chiewanichakorn et al, 2004) that investigated composite sections (made up of a concrete slab attached to a steel girder by means of shear connectors). The commentary author maintained that formulas like the one proposed by the researchers tend to produce increasing effective widths with decreasing interaction between beam and slab. The discusser also pointed out that the researchers' comparison of interior and exterior beam specimens can be slightly misleading, since all beams were T-shaped. The discusser concludes that the foremost reason for maintaining the present limitations on effective width is that concrete cracks. Composite beams have become notorious for developing longitudinal cracks in the concrete slabs over their steel beam sections. In their response, the original researchers contend that the discusser's argument is not valid and they stand strongly behind their findings. The researchers point out several major problems with using the girder deflection approach, versus using compressive bending stress. They conclude that the consequence of imposing the discusser's suggested limitations on effective flange width would be underestimation of the section resistance, especially after concrete cracking.