This　paper　proposes　a　novel　two-stage　structural　damage　detection　strategy　based　on　variational　mode　decomposition　(VMD),　fast　independent　component　analysis　(FastICA)　and　enhanced　whale　optimization　algorithm　integrated　with　Salp　swarm　algorithm　(ESSAWOA).　In　the　first　stage,　VMD　and　FastICA　are　utilized　to　decompose　and　process　the　initial　response　signals　of　the　structure　to　detect　the　damage　time　preliminary.　In　the　second　stage,　ESSAWOA　algorithm　is　employed　to　identify　the　structural　parameters　(e.g.,　stiffness,　mass　or　damping　ratio)　at　different　periods　of　time　to　determine　the　location　and　extent　of　the　damage.　To　investigate　the　performance　of　the　strategy,　the　simulation　tests　in　six　damage　scenarios　are　carried　out　on　a　three-story　numerical　model.　Then,　the　superiority　of　the　parameter　identification　method　based　on　ESSAWOA　is　verified　on　a　seven-story　simulation　model.　Finally,　experimental　verification　on　a　laboratory　seven-story　steel　frame　is　conducted　to　further　validate　the　accuracy　of　the　proposed　strategy.　The　results　in　both　numerical　simulations　and　experimental　validation　prove　that　the　two-stage　strategy　can　effectively　detect　the　time,　location　and　extent　of　the　damage　in　the　frame　structure.　Furthermore,　it　has　good　applicability　and　robustness.