Three-Dimensional Modeling of Long-Term Structural Behavior of Wood-Concrete Composite Beams: Fid-Bau Portal

Three-Dimensional Modeling of Long-Term Structural Behavior of Wood-Concrete Composite Beams

Fragiacomo, Massimo / Balogh, Jeno / To, Lam / Gutkowski, Richard M.

This paper presents a three-dimensional (3D) numerical model for capturing the time-dependent behavior of layered wood-concrete composite beams with notched shear key interlayer connections, subject to long-term static load and simultaneous exposure to naturally changing ambient environmental conditions, including temperature and relative humidity. For the wood material, the research extends the formulation of a previous rheological model, originally proposed for uniaxial stress state of wood exposed to moisture variations, to 3D finite-element modeling with a multiaxial stress state. For the concrete material, a standard creep model for uniaxial stress states was approximated using a generalized Maxwell’s model and then expanded to 3D formulations. The 3D model described in this paper was implemented via external user subroutines in the commercial software ABAQUS. Finite-element models for a wood-concrete composite beam with notched shear key were developed to model the diffusion problem of moisture content and the heat transfer when the beam is exposed to the environment. The moisture content, temperature profiles, and long-term static loading are used as input parameters for the time-dependent analysis problem involving the expanded material models. The results of numerical models are compared and verified with available experimental results as well as with numerical results obtained using a more simplified one-dimensional (1D) beam model previously developed. Although the improvement in accuracy compared to the 1D model is insignificant, the 3D model has the advantage of not requiring mechanical and rheological characterization of the connection, which can only be carried out via expensive short- and long-term experimental tests.