Assessment of a Macro-Model Component-Based Approach for Steel-Concrete Composite Joints in Seismic Areas

The structural design of beam-to-column joints in steel-concrete composite frames is particularly challenging, especially in seismic conditions. Special attention is needed for the optimal detailing of joint components and corresponding resisting mechanisms. In this regard, component-based approaches are particularly efficient in computational terms, but are often affected by intrinsic limits and ranges of applicability. The most important mechanisms and behaviours of single steel and concrete components, as well as their mechanical interaction under seismic events, should be properly taken into account. This paper shows the potential and validity of the harmonized non-linear formulation that has been elaborated in the framework of past DPC-ReLUIS Italian project tasks (and guidelines) for the characterization of bolted and welded joints in seismic resistant steel-concrete composite frames. The analytical calibration of steel and concrete components is assessed for three different beam-to-column joint configurations, with the support of efficient numerical models developed in Sap2000. Monotonic and cyclic results are discussed to analyse the stiffness and resistance parameters of each component, as well as their role in the joint performance, with a special attention for the mechanisms 1, 2 and 3 of the superimposed slab.