Innovative UHS Steel Material for Tension-Only Braced CFS Walls

Abstract

Lightweight Steel (LWS) systems, made of Cold Formed Steel (CFS) profiles, are widespread in seismic areas and often preferred to traditional systems. Improving structural performances in order to have higher building is now the goal, which could be achieved thanks to the use of steel innovative material. In particular, to increase the seismic performances of CFS buildings, the University of Naples “Federico II”, in cooperation with the Italian company Lamieredil S.p.A., has developed an innovative Lateral Force Resisting System (LFRS). The LFRS mainly consists of CFS frame (studs and tracks) braced by “V” shaped pre-tensioned Ultra High Strength (UHS) steel bars. The bracing was designed to be able to limit global displacement of structure, working as elastic spring, and to dissipate seismic energy by yielding. In order to prove the effectiveness of the new system, an extensive experimental campaign has been conducted. This paper focuses on material and component tests, describing tension tests on traditional materials and UHS steel, creep tests on UHS steel and nut-bar assembly tests.

Seismic Response of Innovative CFS Walls Braced With Uhs Steel Bars: Experimental Investigation

“…A UHS steel (fy=1300 MPa, fu=1450 MPa) is adopted for the diag-onal braces, while chord studs, tracks, blocking and flat straps are made of S280 GD+ Z steel grade, and devices for pre-tensioning and hold-downs are made of S355 steel grade (fy=355 MPa, fu=470 MPa). More details about the innovative wall and the design phase are available in [26].…”