During　the　construction　process　of　half　steel　plate　reinforced　concrete　(HSC)　roofs,　the　structural　gravity　and　construction　loads　are　born　by　the　steel　plates　in　the　roof,　which　are　temporarily　used　as　templates　and　braces.　After　the　concrete　hardens,　the　concrete,　steel　plates　and　reinforcing　steel　will　collaboratively　resist　the　external　load　through　combined　action.　In　this　paper,　the　deactivation　element　and　trace　element　techniques　are　applied　to　simulate　the　construction　process　of　the　HSC　structures.　Firstly,　a　numerical　model　of　large-span　HSC　beam　is　developed　to　simulate　the　experiment　on　a　typical　component.　The　effectiveness　of　the　numerical　model　is　confirmed　and　the　bond　slip　between　concrete　and　steel　plates　is　investigated　via　the　simulation.　Then,　the　deactivation　element　and　trace　element　techniques　are　used　based　on　the　numerical　model　to　study　the　mechanical　properties　of　the　one-time　formed　and　the　multi-step　formed　HSC　beam　specimens.　The　results　show　that　the　final　bearing　capacity　and　the　initial　stiffness　of　the　specimen　considering　the　construction　process　reduce　slightly.　The　construction　process　primarily　increases　the　final　deformation　of　the　specimen.　Finally,　the　roof　system　is　simulated　to　study　its　stress　and　deformation　after　construction　process,　providing　a　reference　for　the　design　of　such　roof　structures.　©,　2015,　Tsinghua　University.　All　right　reserved.