Title: Elastic Torsional Stiffness of Prestressed Concrete Elastic Torsional Stiffness of Prestressed Concrete AASHO Girders

Author(s): K. G. Tamberg

Publication: Journal Proceedings

Volume: 62

Issue: 4

Appears on pages(s): 479-492

Keywords: beam, bridge, design, girder, prestressed concrete, shear, slab, stress, torsion

DOI: 10.14359/7706

Date: 4/1/1965

Abstract:
Torsional stiffness values relating to four prestressed concrete AASHO girders have been calculated by the use of finite differences. Torsional stiffness values have been calculated for the girders themselves and for the girders plus 7 in. concrete slabs, both interconnected and acting separately but with the girders and slabs rotating through the same angle. The various widths of the 7-in. slabs considered fall into two major categories: (a) modulus of elasticity of the slab, Es, equal to modulus of elasticity of the girder, EC; (b) modulus of elasticity of the slab equal to 0.77 times the modulus the girder. Graphs relating the torsional stiffness values, K, to various slab widths for the four AASHO girders have been produced. The stiffness values read off the graphs may be used directly in the design of bridge decks when, for example, the Guyon-Massonnet or Hendry and Jaeger load distribution theories are used. Newton’s interpolation function has been used to calculate torsional shear stresses.