To　enhance　post-punching　strengths　and　deformation　capacities　of　flat　plate-column　joints　for　mitigating　progressive　collapse,　two　strengthening　methods　including　stirrups　and　embedded　ring　beams　within　the　joint　regions　were　proposed.　An　experimental　test　program　on　six　flat　plate-column　joint　specimens　with　in-plane　constraints　was　conducted　under　the　modes　of　upward　punching　shear　failure　(UPS　mode)　and　downward　punching　shear　failure　(DPS　mode).　The　specimens　included　two　conventional　specimens　without　strengthening　(UPS/DPS),　two　specimens　with　stirrups　(two-legged　closed　ties,　UPS-S/DPS-S)　and　two　specimens　with　ring　beams　(UPS-R/DPS-R).　The　test　results　showed　that,　in　comparison　to　UPS/DPS,　the　average　post-punching　displacements　in　UPS-S/DPS-S　and　UPS-R/DPS-R　were　increased　by　25%　and　32%,　respectively,　along　with　64%　and　50%　enhancement　in　the　corresponding　post-punching　shear　strengths.　Numerical　simulations　were　also　performed　to　analyze　the　effects　of　different　stirrup　and　ring　beam　configurations　on　the　post-punching　strengths　and　deformation　capacities.　Numerical　results　suggested　that　double　stirrups　(four-legged　closed　ties)　installed　surrounding　the　column　stub　could　lessen　joint　damage　and　further　improve　punching　shear　and　post-punching　strengths　by　15%　and　9%,　respectively,　comparing　to　UPS-S/DPS-S.　For　ring　beam　specimens,　under　DPS　mode,　the　first　punching　shear　failure　inside　the　ring　beams　can　be　prevented　by　their　inner　edges　directly　connected　to　the　column.　The　post-punching　deformations　and　strengths　of　this　specimen　were　increased　by　at　least　10%,　comparing　to　DPS-R.　Numerical　simulation　of　UPS-R　further　showed　that　the　strengthening　effect　also　depends　on　the　constraints　provided　by　the　concrete.