Condition　assessment　of　bridges　has　become　increasingly　important.　In　order　to　accurately　simulate　the　real　bridge,　finite　element　(FE)　model　updating　method　is　often　applied.　This　paper　presents　the　calibration　of　the　FE　model　of　a　reinforced　concrete　tied-arch　bridge　using　Douglas-Reid　method　in　combination　with　Rosenbrock　optimization　algorithm.　Based　on　original　drawings　and　topographie　survey,　a　FE　model　of　the　investigated　bridge　is　created.　Eight　global　modes　of　vibration　of　the　bridge　are　identified　by　ambient　vibration　tests　and　the　frequency　domain　decomposition　technique.　Then,　eight　structural　parameters　are　selected　for　FE　model　updating　procedure　through　sensitivity　analysis.　Finally,　the　optimal　structural　parameters　are　identified　using　Rosenbrock　optimization　algorithm.　Results　show　that　although　the　identified　parameters　lead　to　a　perfect　agreement　between　approximate　and　measured　natural　frequencies,　they　may　not　be　the　optimal　variables　which　minimize　the　differences　between　numerical　and　experimental　modal　data.　However,　a　satisfied　agreement　between　them　is　still　presented.　Hence,　FE　model　updating　based　on　Douglas-Reid　method　and　Rosenbrock　optimization　algorithm　could　be　used　as　an　alternative　to　other　complex　updating　procedures.　©　2014　Periodical　Offices　of　Chang＇an　University