One　static　and　four　dynamic　collapse　experiments　have　been　conducted　on　beam-column　assemblies　under　a　middle-column　removal　scenario　to　investigate　the　dynamic　collapse　responses.　All　the　assemblies　had　identical　configurations,　materials,　and　boundary　conditions.　Numerical　analyses　were　conducted　for　an　in-depth　comprehension　of　different　behaviors　of　the　assemblies　under　static　and　dynamic　collapse　scenarios.　To　ease　the　assessment　of　the　dynamic　collapse　responses　of　the　beam-column　assemblies,　a　new　assessment　procedure　was　proposed　based　on　the　energy-method　and　was　proved　to　be　efficient　and　accurate　by　comparing　with　the　experimental　and　numerical　results.　Research　indicated　that　the　dynamic　collapse　behaviors　of　the　assemblies　were　influenced　by　two　key　factors,　i.e.,　the　dynamic　stress　distribution　characteristics　and　the　material　strain　rate　effect.　Under　the　dynamic　collapse　scenario,　the　structural　resistance　of　the　assemblies　was　impaired　during　the　stage　of　compressive　arch　action　(CAA)　due　to　the　dynamic　stress　distribution　characteristics.　Whereas　the　material　strain　rate　effect　could　enhance　the　resistance　in　the　stage　of　the　catenary　action　(CA).　Moreover,　both　factors　contributed　to　increasing　the　largest　deformation　of　the　assemblies.　The　dynamic　amplification　factor　(DAF)　was　also　evaluated　based　on　the　proposed　assessment　procedure　and　the　traditional　one.　At　the　critical　deformations　during　the　CAA　and　CA　stages,　the　DAFs　obtained　through　the　proposed　procedure　were　found　to　be　greater　than　those　determined　by　the　traditional　procedure　in　which　the　dynamic　stress　distribution　characteristics　and　the　material　strain　rate　effect　were　both　neglected.　Further,　the　DAFs　suitable　for　practical　engineering　design　were　also　discussed.