Structural Steel DesignPlate Girders

Dr. Seshu Adluri

Plate girders -Dr. Seshu Adluri

Plate Girders

Deep girdersThree platesWelded or boltedRolled sections not enoughUsually 3’-20’ deepWWF sections in the handbook can be usedWeb buckling

stiffenersVariable c/s

Plate girders -Dr. Seshu Adluri

Plate girder stiffeners

Plate girders -Dr. Seshu Adluri

Plate Girders

Plate girders -Dr. Seshu Adluri

Plate Girders

Plate girders -Dr. Seshu Adluri

Plate Girders

Plate girders -Dr. Seshu Adluri

Bridge girders

Plate girders -Dr. Seshu Adluri

Beams in Bridges

Plate girders -Dr. Seshu Adluri

Beams in Bridges

Plate girders -Dr. Seshu Adluri

Plate girders

Plate girders -Dr. Seshu Adluri

Fabrication

Plate girders -Dr. Seshu Adluri

Plate Girders Steel plate girders

Class 3 flanges & class 4 websReduce web area for MrStiffen the web to increase Vr

Useful in pure bending as well as in beam-columnsDesign Clauses: CAN/CSA-S16

Bending strength as per Clauses 13.6 & 7Shear strength as per Clause 13.4 Local buckling check: Clause 11 (Table 2)Special provisions: Clause 14Deflection limits: Appendix D

Plate girders -Dr. Seshu Adluri

Plate buckling

Different types of buckling depending on

b/t ratio Webs and flanges have different limitsend conditions for plate segmentsUse Table 2 for beams and beam-columns

Plate girders -Dr. Seshu Adluri

Slender webs buckle easily due to shear or bending

Use reduced effective c/s

orUse reduced capacity

Plate Girders

Plate girders -Dr. Seshu Adluri

Slender webs buckle easily due to shear or bending

Plate Girders

Plate girders -Dr. Seshu Adluri

Web buckling

Plate girders -Dr. Seshu Adluri

Plate Girders

Plate girders -Dr. Seshu Adluri

Plate Girders

Plate girders -Dr. Seshu Adluri

Stiffeners are Important

June 1970, Milford Haven bridge over the River Cleddau in the UK

Plate girders -Dr. Seshu Adluri

Plate Girders

Recall compression field action in reinforced concrete beams

Compression struts develop because of the presence of stirrups

Plate girder tension field action develops because of the placement of vertical (and horizontal) stiffeners