Shape　memory　alloy　(SMA)　is　becoming　a　popularly　studied　smart　material　in　the　field　of　structural　control.　The　feasibility　of　utilising　an　SMA　in　a　tuneable　mass　damper　to　reduce　the　excessive　vibration　of　a　timber　floor　system　was　revealed　in　a　pilot　study.　However,　the　in-service　excitations　on　a　floor　can　be　complex　and　involve　more　frequencies　and　randomness;　therefore,　this　paper　aims　to　assess　the　effectiveness　of　the　SMA-based　semi　active　TMD　in　a　real-scale　timber　floor,　where　the　free　vibration　and　human　footfall-induced　vibration　are　considered　as　inputs.　This　study　is　conducted　using　numerical　simulations　on　OPENSEES.　By　reducing　the　floor　vibration　at　a　range　of　frequencies,　both　cooling　and　heating　the　SMA　are　effective　in　retuning　the　off-tuned　TMD　and　reducing　the　structural　response.　Footfall　excitation　involves　more　than　one　excitation　frequencies,　and　the　higher　dominant　frequencies　can　resonate　with　the　off-tuning　frequencies,　increasing　the　structural　response.　Simulation　results　demonstrate　that　retuning　using　SMAs　can　effectively　lower　the　structural　response　at　a　wide　range　of　frequencies,　thus　attenuating　the　footfall-induced　vibration.