High strength steel in seismic resistant building frames

The aim of “HSS-SERF” project was to investigate and evaluate the seismic performance of dual-steel building frames, realized from two different steel grades: Mild Carbon Steel and High Strength Steel. A comprehensive set of dual-steel frames (moment resisting, concentrically and eccentrically braced) were designed, which allowed the identification of realistic member sizes for both mild carbon steel and high strength steel components. Several practical solutions for bolted and welded beam-to-column joints were identified and designed. Further, an extensive numerical program was carried out for the seismic performance evaluation of frames. The ductility and over-strength demands, and q-factors associated with different performance levels were evaluated. Furthermore, experimental and numerical investigations were carried out on joint assemblies and components. Guidelines were elaborated for the conceptual design and performance based design of dual-steel frames under seismic actions, and the technical and economic efficiency of dual-steel structures vs. conventional ones were finally evaluated. The main outcomes of the project consist in: (i) development and characterisation in terms of global ductility and over-strength demands of dual-steel frames with composite columns (innovative solutions in European context); (ii) development of design recommendations; (iii) proposal of innovative solutions for beam-to-column joints with composite columns; (iv) recommendation for weld details and appropriate component method design approaches; (v) evaluation of technical and economic efficiency of the dual-steel approach.