Deformation behavior at SLS of welded I-section steel beams with longitudinally profiled flanges

Welded I-section steel beams with longitudinally profiled (LP) flanges, in which LP steel plates are utilized as the flanges may be applied to achieve structural optimization. Their special geometry raises challenges in deformation design, which leads to requirement of calculation equations. In this paper, theoretical solutions for mid-span deflections considering the influence of variable flange thickness have been deduced with the unit-load method and mathematical integration, and three different static loading conditions are incorporated. Then the reliability is verified by comparing with finite element (FE) models and test results. Straightforward design formulae are proposed by introducing a coefficient on the basis of formulae of conventional beams, which depends on all independent geometrical parameters and is determined through a nonlinear fitting of abundant theoretical results. It also indicated that remarkable amount of steel could be saved with a certain amount increase of additional deformation. The formulae developed herein for SLS deformation design of LP beams may be applied in practical construction design of building and bridge structures, which may also promote application of such advanced steel products.