Numerical investigation on structural behavior of arched cellular steel beam

Abstract

In recent year due to its design and construction advantages, engineers are increasingly utilizing open web steel sections (cellular) in their designs. Design advantages include a reduced weight per unit length of beam and an improved flexural stiffness due larger section modulus resulting from the increased depth, thus allowing longer spans, which provide for a more open floor plan. Construction advantages include the ability to run electrical, mechanical and plumbing utilities through the openings, which can save several inches of floor-to-floor height. The open webs also provide aesthetic advantages when used in structures with exposed beams. These added benefits make cellular beams an efficient and cost effective material for modern building constructions. The evolution of the fabrication technology and the aesthetical and mechanical performances implied the extension of the fields of application of these beams. Nowadays, the cellular beams can be designed using a variation of heights (tapered beams) or a curvature (arched beams). However, in spite of numerous advantage of curved cellular steel beam previous studies mainly focused on the structural behavior arched steel beam with solid webs and little research has been reported for structural in plane stability and performance of cellular arched steel .to narrow this gap This paper presents a study on in plane structural strength of cellular steel arches using validated ABAQUS/CAE standard version 6.14 finite element program for the nonlinear elastic-plastic analysis of cellular steel arches. In these paper to investigate the in-plane elastic-plastic buckling and strength of pinned circular and parabolic cellular arches of total 32 samples were randomly selected considering degree of curvature(shallow and deep) ,geometry of arch(parabolic and circular) and applicability. The finite element program considers the effects of large deformations, material nonlinearities and initial geometric imperfection in predicting the elastic-plastic behavior of cellular steel arches under mid span concentrated and uniform radially distributed vertical loads ,which induce combined bending and compression in the arch .the complex effect of rise-to-span ratio, arch geometry and radius of curvature on the in plane elastic-plastic stability and strength of cellular steel arches are included and elucidated in these study. Finally numerical result buckling load to in plane deflection, buckling load to out of plane deflection and mode of failure from finite element analysis extracted, further analyzed and interpreted to draw conclusion. In conclusion, the stiffness of arched cellular beam is directly proportional to rise-to-span ratio regardless of arch geometry and degree of curvature under mid span concentrated load ,but this is valid up to rise-to- span ratio(Hs/L=0.35) and (Hs/L=0.419) for circular and parabolic arch respectively under uniform vertical load. Under the same rise-to-span ratio deep parabolic arches are structurally stiffer and can carry larger load than deep circular cellular arches. Increasing radius curvature without altering rise-tospan ratio reduces the stiffness of arched cellular steel under mid-point load.