NCBF1-R1: UW Non-Seismic Concentrically Braced Frame (NCBF) with Repaired Welded Continuous Shear Tab and Ductile HSS Brace

This specimen consisted of a single-bay one-story concentrically braced frame with single-diagonal bracing. The frame and connections from NCBF1 were reused, but the non-seismically compact brace was replaced with a highly ductile HSS brace. As in NCBF1, connection deficiencies included gusset plate yielding of the Whitmore section, gusset plate shear yielding, gusset plate-to-beam and gusset plate-to-shear tab weld fracture, brace net section rupture, brace block shear rupture, and gusset plate block shear rupture. AWS E70T-7 weld metal, which does not meet minimum toughness requirements for demand critical welds, was used except on the gusset plate-to-beam and shear tab-to-column welds, where notch-tough weld metal was used. 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.

该试件为单跨一层单斜杆同心支撑框架。试件复用了NCBF1的框架及节点，但将非抗震紧凑支撑替换为高延性HSS支撑。与NCBF1相同，节点缺陷包括：Whitmore截面的节点板屈服、节点板剪切屈服、节点板-梁及节点板-剪力板焊接断裂、支撑净截面断裂、支撑块体剪切断裂及节点板块体剪切断裂。除节点板-梁及剪力板-柱焊缝采用缺口韧性焊接材料外，其余部位均使用AWS E70T-7焊接材料——该材料不满足重要受力焊缝的最低韧性要求。试件通过螺栓连接于北侧梁的加载梁进行拟静力加载，采用循环幅值递增的反向加载方案。试件上安装了传统物理传感器与光学传感器，部分区域经粉刷处理以观测屈服现象。