Understanding　how　pedestrians　interact　with　the　footbridge,　in　particular　studying　dynamic　actions　caused　by　pedestrian　loads　on　footbridges,　engineers　can　address　any　design　deficiencies,　such　as　excessive　deflection,　resonance,　or　discomfort　experienced　by　pedestrians　during　bridge　usage.　For　this,　the　paper　consists　in　two　main　parts:　In　the　first　part,　we　extensively　examine　various　factors　essential　for　accurately　modeling　the　dynamic　actions　induced　by　individual　pedestrians　or　groups　of　pedestrians　on　footbridges.　Our　focus　includes　an　analysis　of　relevant　experimental　studies　conducted　abroad,　specifically　regarding　the　closure　of　the　Millennium　Bridge.　This　section　extensively　discusses　the　identified　issues　and　explores　different　mathematical　models,　particularly　those　capable　of　simulating　dynamic　forces　resulting　from　walking,　jogging,　or　jumping,　whether　by　an　individual　or　a　group　of　walkers.　The　second　part　of　the　study　centers　around　utilizing　Finite　Element　Method　(FEM)　models　to　analyze　a　specific　footbridge　located　in　Carbonia.　This　footbridge　was　inaugurated　in　November　2001　but　had　to　be　closed　within　a　year.