This　paper　presents　a　comprehensive　theoretical　analysis　of　a　concrete-filled　steel　tubular　(CFST)　arch　bridge　under　tridirectional　spatial　seismic　motions　using　the　pseudo-excitation　method.　Formulations　for　modelling　tridirectional　spatial　ground　motions　at　varying　site　conditions　are　first　derived.　A　site　response　analysis　is　presented　for　the　tridirectional　motions　based　on　deterministic　wave　propagation　theory,　assuming　that　the　base　rock　motions　consist　of　out-of-plane　SH　wave　or　in-plane　combined　P　and　SV　waves　propagating　into　the　multiple　layered　site　with　an　assumed　incident　angle.　Integration　between　the　structural　health　monitoring　(SHM)　technique　and　the　structural　seismic　analysis　is　proposed　and　conducted　for　the　finite　element　(FE)　model　calibration　of　the　CFST　arch　bridge　through　the　model　updating　approach.　Using　the　calibrated　FE　model,　stochastic　seismic　analysis　of　the　CFST　arch　bridge　is　conducted　in　a　comprehensive　and　systematic　way,　by　considering　the　dimensionality,　incoherence　effect,　wave-path　effect　of　ground　motions,　and　local　site　effects　with　different　and　irregular　site　conditions.　Critical　conclusions　are　drawn　and　can　be　applied　in　the　actual　seismic　design　of　the　half-through　CFST　arch　bridges　under　tridirectional　multiple　excitations.　(C)　2013　Elsevier　Ltd.　All　rights　reserved.