Long-term behavior of composite concrete girders made continuous

Time-dependent effects play an important role in the design process of concrete structures. In order to predict time-dependant effects in concrete structures, engineers need reliable data for creep and shrinkage properties of concrete and analytical procedures to account for these effects. Various researches all over the world develop many software applications in order to calculate these effects. These applications accounts for various kind of concrete nonlinearity. In the case of long-term structural behavior viscous properties are of interest. Benefits of powerful programs in relate to simplified methods (from Dishinger's method to AAEM) lies in numerical integration of basic Voltera integral equation, that describes linear creep low, with step-bystep procedure. Programs are usually verified by comparing calculated results with the measured values of experimental test results. In this paper numerical simulation of the several experimental long-term investigations of composite concrete beam made continuous, using nonlinear FEM model of DIANA application is presented. Since the analytical results appear to be quite sensitive to material properties, some comparisons are made, using several proposals for creep and shrinkage properties of concrete. Comparisons of estimated results by DIANA and some simplified methods for the same material properties are made as well