NCBF1-R5: UW Non-Seismic Concentrically Braced Frame (NCBF) with Bolt-Reinforced Welded Continuous Shear Tab and Concrete-Filled HSS Brace Retrofit

This specimen consisted of a single-bay one-story concentrically braced frame with single-diagonal bracing. The frame was intended to be representative of a rehabilitated non-seismic concentrically braced frame (NCBF) with continuous welded shear tab connections at brace-beam-column intersections. The connection used in NCBF1 was rehabilitated by adding bolts to the shear tab to reinforce the welded beam-to-shear tab and gusset plate-to-shear tab connections. In addition, the non-seismically compact HSS brace (b/t = 27.0 > 13.8) was filled with concrete to prevent severe local buckling, improving its fracture life. Since the existing gusset plates and shear tabs were used, some deficiencies with respect to the 2010 AISC Seismic Provisions remained. Connection deficiencies included gusset plate yielding of the Whitmore section, gusset plate shear yielding, gusset plate-to-beam and -shear tab weld fracture, brace net section rupture, brace block shear rupture, and gusset plate block shear rupture. The specimen was loaded quasistatically through a load beam bolted to the north beam using a reversed cyclic increasing amplitude loading protocol. Traditional physical sensors and optical sensors were installed on the specimen. Portions of the specimen were whitewashed to detect yielding.