Shear strength of steel-concrete composite “NPS® Basic” truss beams: Fid-Bau Portal

Shear strength of steel-concrete composite “NPS® Basic” truss beams

Galik, William D. / Calvi, Paolo M.

Highlights • Experiments on composite steel-trussed beams show that both concrete and steel contribute to the shear strength. • The numerical shear database is expanded via a large parametric case study of composite steel-trussed beams. • The shear strength of steel-trussed composite beams is best predicted by approaches that allow for strut reorientation.

Abstract NPS® Basic beams are steel-concrete composite truss beams with a steel-plate bottom chord and plain-bar top chord, completed with concrete cast in situ, that are part of the NPS® frame system. Determining the shear behavior and strength of NPS® Basic beams is challenging due to the complex resisting mechanisms involved and because of the various peculiarities these beams present. This paper provides the necessary theoretical, numerical and experimental evidence for the identification of a rational design procedure of NPS® Basic beams subjected to shear loads. The state of the knowledge of the shear response of steel-concrete composite truss beams is first summarized, including available experimental evidence and code-based design methodologies. A preliminary assessment of these shear design approaches is performed, by comparison with the limited experimental results available. Then, the existing shear behavior database is expanded by generating a large amount of data via non-linear numerical analyses (calibrated against the available experimental evidence) of a set of shear-critical case-study beams. The results of this parametric study are combined with the available experimental evidence to support recommendations of a rational shear design approach.