Analysis of gusset plate of contemporary bridge truss girder

Abstract

Trussed structures in modern bridge building usually have “W” bracing. Structural joints are often based on application of gusset plates. Experimental tests of stress distribution in such gusset plates are rather sparse. Lab testing of scaled bridge truss girder was carried out in Poznań University of Technology in Poznań. Investigation into stress distribution in gusseted joint was carried out. Test results were put against results obtained from analyses of two finite element models: beam-element model and shell-element model. Normal stress and Huber-Mises equivalent stress distributions within gusseted joint were analysed. General conclusions are: a) normal stress distribution in gusseted joint cross-section, perpendicular to truss flange axis, is nonlinear and extreme stresses occur near cross-section edges, b) Huber-Mises equivalent stress distribution in the cross-section of gusset plate near its connection to truss flange is nonlinear and extreme stresses occur near centre of the cross-section, c) assessment of normal stresses in gusseted joints should not be carried out with an aid of beam-element modelling, d) it is possible to assess Huber-Mises equivalent stresses in gusset plate near its welded connection to rigid flange with an aid of beam-element modelling if non-uniform distribution of shear stress is taken into account, e) shell-element modelling of gusseted joint provides satisfactory accuracy of normal and equivalent stress assessment, f) beam-element modelling of friction grip bolts is sufficiently accurate for shell-element models of steel joints analysed within elastic range of behaviour.