Fire-induced　loss　of　column　members　is　a　unique　scenario　of　localized　failure　that　could　further　trigger　the　progressive　collapse　of　frame　structures.　This　paper　presents　an　experimental　study　on　the　anti-collapse　performance　of　beam-column　assemblies　with　WUF-B　connections　under　a　column　removal　scenario　due　to　fire　conditions.　A　total　of　ten　assemblies　included　nine　specimens　subjected　to　different　fire　conditions,　and　the　remaining　single　specimen　without　fire　treatment　was　designed　and　tested　under　a　fire-induced　middle　column　loss　scenario.　The　effect　of　the　fire　conditions　on　the　anti-collapse　mechanism　along　the　whole　loading　process　was　comprehensively　analyzed.　The　test　results　demonstrated　that　all　beam-column　assemblies　fractured　at　one　beam　end　of　the　middle　column　whether　the　specimens　had　been　subjected　to　the　fire　treatment　or　not.　Owing　to　the　pressure-bearing　failure　process　with　high　ductility　after　the　fracture　of　the　lower　flange,　the　WUF-B　connections　could　effectively　maintain　the　capacities　of　the　specimens　at　high　levels　and　made　the　specimens　develop　greater　deformation　capacity.　During　the　overall　loading　sequence,　the　flexural　mechanism　was　the　principal　mechanism　against　the　progressive　collapse　of　the　structure,　while　the　catenary　mechanism　generally　played　a　leading　role　after　the　vertical　displacement　exceeded　50%　of　the　maximum　displacement.　Both　the　flexural　and　catenary　mechanism　resistances　declined　to　different　extents.　The　anti-collapse　performances　of　the　post-fire　assemblies　deteriorated　compared　with　those　without　fire　treatment.　Significantly,　with　the　increasing　fire　temperatures,　the　mechanical　flexural　actions　gradually　degraded　and　the　respective　catenary　actions　did　strengthen　instead.　However,　the　fire　durations　exerted　a　minor　influence　on　the　development　process　of　the　resistance　mechanism.　The　plastic　rotation　angles　of　assemblies　with　WUF-B　connections　after　fire　conditions　changed　at　the　failure　state　within　the　range　of　0.161　to　0.209　rad　and　the　respective　variation　at　the　limit　state　was　0.202　to　0.278　rad.　By　contrast　with　the　test　plastic　rotation　angles　at　both　failure　and　limit　states,　it　was　found　that　the　modeling　parameters　provided　in　DoD　guidelines　are　too　conservative　for　evaluating　the　progressive　collapse　performance　of　beam-column　assemblies　with　WUF-B　connections.