Title: A Simple Method to Analyse Time-Dependent Forces Developed in Continuous Concrete Structures

Author(s): W. H. Dilger

Publication: Symposium Paper

Volume: 76

Issue:

Appears on pages(s): 325-340

Keywords: continuity (structural); creep properties; frames; loads (forces); reinforced concrete;shrinkage; strains; stresses; structural analysis.

DOI: 10.14359/6794

Date: 10/1/1982

Abstract:
In any concrete frame structure in which the support conditions are changed during or after construction, or in which shrinkage strains are developed, time-dependent forces occur. These forces may be substantial in structures in which continuity is provided at a later stage of construction, or when it is built in stages. A simple method is presented in which the elastic equations (Muller-Breslau) are expanded to include the time-dependent displacements due to (a) the constant statically determinate and in-determinate forces which are present at the beginning of the continuous action and (b) the time-varying forces introduced by creep and shrinkage. Use is made of the relaxation (aging) coefficient which allows to include in a simple way the effects of aging of the concrete in a structural member subjected to varying forces. A number of different practical examples are given to explain the procedure.