Aeroelastic　effects　are　a　fascinating　yet　problematic　phenomenon　that　lies　in　between　the　fields　of　aeronautical　and　bridge　engineering,　as　many　long-span　bridge　decks　show　dynamic　behaviors　similar　to　the　ones　of　wing　airfoils　when　met　with　strong　winds.　In　particular,　modal　damping　is　a　critical　factor　in　understanding　the　dynamic　behavior　of　bridges　when　exposed　to　these　kinds　of　interactions　between　aerodynamic　forces　and　their　structural　elastic　properties.　This　short　contribution　presents　an　in-depth　investigation　of　modal　damping　identification　through　output-only　operational　modal　analysis　(OMA)　in　a　bridge　deck　case　study　in　Norway　subjected　to　still-air　conditions,　where　aeroelastic　damping　can　be　neglected.　However,　in　this　long-span　suspension　bridge,　its　slenderness　implies　having　several　closely-spaced　modes　of　interest　below　1.00　Hz.　Therefore,　the　herein-considered　still　air　wind　condition　represented　a　critical　situation　for　proper　activation　of　some　first　modes　of　interest,　highlighting　that　experimental　OMA　can　not　properly　identify　the　right　value　of　the　expected　structural　damping　ratio　associated　with　those　modes　from　comparisons　with　other　literature　results.　©　2025　by　the　Authors　and　International　Group　of　Operational　Modal　Analysis.　All　rights　reserved.