ABSTRACT
This paper considers the in-plane nonlinear and buckling response of a concrete filled steel tubular (CFST) shallow parabolic arch when the concrete is subjected to the quasi-viscoelastic effects of creep and shrinkage. Under a sustained loading regime, these viscoelastic effects produce time-dependent changes of the deflections of a shallow arch which can lead to the establishment of a geometric configuration at which the arch is no longer stable, and which heralds the onset of potential creep buckling. By using empirical data for the shrinkage and creep response of CFST sections having a circular cross-section in a model which uses the Age-Adjusted Effective Modulus Method, the equations for the in-plane nonlinear and buckling response of a CFST arch are derived in analytic form, and these are proposed as a rational means for determining the structural life of an arch. The use of the theory is demonstrated with an example.
