To　study　the　influence　of　slabs　on　the　progressive　collapse　resistance　of　reinforced　concrete　(RC)　frame　structures,　two　1:3-scaled　substructures　-　S1　(with　slab)　and　B1　(without　slab)　-　were　comprehensively　tested.　Both　specimens　had　two　spans,　and　each　span　had　a　length　of　2　m.　The　width　of　the　floor　slab　for　S1　is　1　m　for　each　side　of　the　centerline　frame　beam.　The　two　opposite　sides　of　the　specimens　were　completely　fixed,　and　the　remaining　opposite　sides　were　free.　Two　hydraulic　jacks　were　applied　at　the　top　and　bottom　of　the　middle　beam-column　joint.　At　the　beginning　of　the　experiment,　these　two　hydraulic　jacks　applied　a　pair　of　small　balanced　forces　synchronously.　Next,　the　bottom　jack　maintained　the　constant　force　and,　at　the　same　time,　gradually　increased　the　force　of　the　top　jack.　Displacement　controlled　loading　was　used　to　simulate　the　failure　of　the　middle　column.　By　analyzing　the　loadcarrying　capacities　of　S1　and　B1,　the　influence　of　the　slab　on　the　progressive　collapse　resistance　of　the　RC　frame　structures　was　discussed.　©　2014　American　Society　of　Civil　Engineers.