Large-scale shaking table tests of a six-story floor-by-floor assembled CFS frame-framing shear wall structure

Abstract

To study the seismic performance of a proposed multi-story floor-by-floor assembled structure using cold-formed steel (CFS) frame with square columns and double-channel beams connected by novel joints, and CFS framing walls as shear walls, shake table tests were conducted on a 2:3 scaled six-story CFS frame-framing shear wall structure (CFSF-FSWS) using bidirectional seismic inputs. A prefabricated concrete floor slab was proposed utilizing the channel section beams as the molds during prefabricating processes. The CFS framing shear walls were designed with various configurations researched before: framed or trussed skeleton, single or double side sheathing, flat or corrugated steel sheathing sheet. The observed damages, dynamic properties, seismic responses and failure mechanisms of the CFSF-FSWS under different peak ground accelerations (PGAs) were analyzed. The CFS frame carried gravity load, and the horizontal earthquakes were mainly resisted by CFS framing shear walls. The results indicated a good deformation capacity and seismic performance of the CFSF-FSWS building. The damping ratio of the test model gradually increased with the accumulation of damage, varying between 3.30%∼6.95%. After all seismic loading, the CFS frame remained intact and the damages were concentrated on the CFS framing shear walls, achieving the design objective of “separated gravity and lateral resisting systems”.