Fifth　Yangtze　River　Bridge　in　Luzhou　is　an　extra-long　span　half-through　steel　box　arch　bridge　with　thrust.　The　main　girder　deck　system　is　subject　to　the　direct　action　of　vehicles,　pedestrians,　rail　transit　and　other　loads.　At　the　same　time,　it　produces　a　huge　horizontal　thrust　to　the　arch　base　foundation　through　the　slings　and　arch　ribs.　Therefore,　the　selection　of　the　main　girder　structural　type　is　directly　related　to　the　comfort　of　traveling,　the　steel　consumption　economy　and　the　arch　base　foundation　engineering　volume.　The　three　main　girder　schemes　are　compared　from　the　structural　form　of　the　rail　transit,　the　stiffness　demand,　the　deformation　limit　and　the　force　performance.　The　two-side　box　type　flat　steel　box　girder　is　finally　selected　as　the　deck　system.　©　The　Author(s),　under　exclusive　license　to　Springer　Nature　Switzerland　AG　2025.