Modelling of the behavior of steel-concrete-steel composite beams with a full or a partial composite action
Résumé
Steel-concrete-steel (SCS) composite structures are modular structures combining two steel plates in the center of which a core of concrete is poured. This material presents the advantages of reinforced concrete while offering higher tightness, durability and strength under some extreme solicitations [1]. The efficiency of this structure is essentially based on the connection system between steel plates and concrete, which is performed by steel ties or dowels. Usually designed to assume a full composite action, in some cases (connector failure, construction choice, etc.), this connection may not be sufficient, which leads to the apparition of a partial composite action between steel plates and concrete core. This study focuses on the modelling of the behavior of SC structures in the case of a full or a partial composite action. This involves assessing the influence of simulation hypothesis on the global (force-displacement) and local (mechanical degradation, failure mode) behaviors and proposing a simulation methodology adapted in both cases. From the simulation of two three point bending beams [2], it is especially demonstrated that the interface conditions strongly influence the simulation results. If a “perfect” (“no-slip”) relation between steel plates and concrete is sufficient for a high number of connectors, an additional methodology is necessary when a partial composite action is expected. The methodology is presented and validated by a comparison to the experimental results.