Ultimate strength of tapered steel plate girders under combined shear and bending moment

Abstract

The chapter discusses the ultimate strength of tapered steel plate girders under combined shear and bending moments. Tapered plate girders are efficient structural elements used in steel bridges and buildings where high shear forces and bending moments appear. The design of these elements leads to elements with optimal cross-sections whose dimensions are obtained according to the bending moment variation and shear forces. The area of the flanges depends principally on the magnitude of the bending moment and the web thickness on the shear force. To obtain a tapered plate girder capable of resisting high bending moments, considering its variation along the longitudinal axis, the cross-section is designed by means of flange plates and the web plate having a depth variation along the longitudinal axis. Usually, the web thickness is reduced for decreasing the self-weight of the tapered plate girder. So, a considerable slenderness of the tapered web is obtained, and the buckling phenomena may occur when the critical web buckling stress is overcome by shear stress on the web. This often results in the elastic range prior to the yielding of the steel.