# A Rate-of-Creep Analysis of Composite Steel-Concrete Cross-Sections

*A time-dependent analysis of a general, monosymmetric, steel-concrete, composite cross-section subjected to constant sustained loading is presented. Dischinger’s differential
constitutive relationship is used to model the inelastic creep and shrinkage strains that develop with time in the concrete parts of the cross-section. The procedure involves a stiffness formulation of the coupled differential equations that describe cross-sectional behaviour and a simple tractable mathematical solution. Compatibility of strain is maintained at every point on the cross-section. The solution is most readily obtained using a programable calculator or small microcomputer, but manual solution is also possible. The method is illustrated by example, and the effects of both creep and shrinkage on the behaviour of the cross-section are determined and discussed.
R. Lawther and R.I. Gilbert*