To　resolve　the　problem　regarding　the　insufficient　robustness　of　the　floor　systems　on　the　half-through　and　through　concrete-filled　steel　tube　arch　bridges,　the　highlights　of　the　robustness　design　are　presented　from　the　angle　of　the　conceptual　design　and　structural　design　and　the　concept　of　the　structural　robustness　and　the　applying　of　the　concept　to　the　bridge　engineering　are　summed　up.　The　failure　of　the　hanger　breaking　of　the　arch　bridges　is　classified　into　three　levels　according　to　the　severity　degrees　of　the　failure　and　further　according　to　the　classification,　the　requirements　for　the　robustness　design　of　the　floor　systems　under　the　situations　that　the　hangers　do　not　break　and　that　the　hangers　break,　but　the　girders　do　not　collapse　are　set　forward.　In　terms　of　the　concept　of　the　robustness,　the　floor　systems　of　the　different　structures　are　classified　into　five　types　and　on　the　basis　of　the　classification,　the　robustness　design　of　the　main　structures　of　the　arch　bridges　is　proposed.　For　the　hangers,　the　failure　safety　limit　state　corresponding　to　the　robustness　design　should　be　designed　and　calculated.　For　the　floor　system　type　four,　the　stiffening　stringers　of　the　floor　system　should　have　sufficient　rigidity　and　bearing　capacity　and　for　the　rigid-frame　tied　arch　bridge,　the　robustness　design　of　the　tie　members　of　the　bridge　should　be　reinforced　and　the　substructure　of　the　bridge　should　be　made　to　have　the　sufficient　safety　margin　of　horizontal　thrust　resistance.　©　2016,　Journal　Press,　China　Railway　Bridge　Science.　All　right　reserved.