Support　settlement　and　cable　slippage　of　a　long-span　suspension　bridge　may　occur　when　it　is　subjected　to　extreme　events.　The　evaluation　of　effects　of　support　settlement　and　cable　slippage　on　the　remaining　capacity　then　becomes　important　before　making　a　retrofitting　decision.　However,　it　is　difficult　to　conduct　such　an　evaluation　on　the　prototype　bridge.　This　paper　therefore　presents　experimental　and　numerical　studies　to　examine　the　effects　of　support　settlement　and　cable　slippage　on　the　structural　performance　of　a　long-span　suspension　bridge　through　a　testbed,　which　include　a　laboratory-based　model　and　an　updated　finite-element　(FE)　model.　Four　support　settlement　cases　are　experimentally　studied　with　two　on　anchorage　settlements　and　two　on　tower　settlements.　Main　cable　slippage　at　the　top　of　towers　is　then　investigated　experimentally　in　two　opposite　directions.　Both　support　settlement　cases　and　cable　slippage　cases　are　also　simulated　using　the　corresponding　FE　model,　and　results　are　compared　with　those　from　the　tests.　Finally,　numerical　studies　are　conducted　to　investigate　cable　slippage　caused　by　large　support　settlement.　The　results　show　that　the　experimental　and　numerical　simulation　using　the　testbed　is　an　effective　way　to　assess　the　effects　of　support　settlement　and　cable　slippage　on　long-span　suspension　bridges.