Gardner&Lockman Model (2000) and its Application in Numerical Analysis of Composite Beams

The paper presents analysis of the stress and deflections changes due to creep in statically determinate composite steel-concrete beam. On the basis of the theory of the viscoelastic body of Arutyunian–Trost-Bažant for determining the redistribution of stresses in beam section between concrete plate and steel beam with respect to time “t”, two independent Volterra integral equations of the second kind have been derived. The creep functions is suggested by the Gardner&Lockman prediction model for time dependent deformations of concrete and compared with FIP CEB MC90-99 model. The elastic modulus of concrete Ec(t) is assumed to be constant in time “t”. Numerical method based on linear approximation of the singular kernal function in the integral equation is presented. Example with the model proposed is investigated