American Society of Civil Engineers


Time-Dependent Stresses in Continuous Precast Bridges


by Walter H. Dilger, M.ASCE, (Prof., Dept. of Civ. Engrg., The Univ. of Calgary, Calgary, Alberta, Canada) and Amin Ghali, M.ASCE, (Prof., Dept. of Civ. Engrg., The Univ. of Calgary, Calgary, Alberta, Canada)

Journal of the Construction Division
, Vol. 102, No. 1, March 1976, pp. 239-252

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Document type: Journal Paper
Abstract: This paper is concerned with a method of construction of bridges built up of precast prestressed concrete members, connected and made continuous by cast-in-situ concrete and a second-stage prestressing. The precast units are assembled on temporary supports, the deck slab and the joints cast and the second stage prestressing introduced by means of continuity tendons shortly before removal of the temporary supports. The deformation of the members due to creep shrinkage of concrete and relaxation of steel cannot develop freely after the members are made composite and continuous. These restraints cause significant internal forces which must be taken into account for accurate evaluation of the stresses at service, several years after construction. A method of analysis is presented for application in design using a computer.


ASCE Subject Headings:
Bridges
Concrete
Concrete bridges
Construction
Creep
Precast concrete
Prestressed concrete
Relaxation (mechanics)
Stress