Many　simply　supported　bridges　have　been　constructed　all　over　the　world.　The　majority　of　them　have　been　affected　by　some　durability　problems　during　their　service　life.　For　this　purpose,　the　concept　of　integral　abutment　bridge　came　out　which　can　achieve　the　requirement　of　road　administrations　to　resolve　the　durability　problems　of　broken　expansion　joints　and　damaged　bearings　fundamentally.　In　this　paper,　a　retrofitting　technology　using　the　concept　of　integral　abutment　bridge　and　developed　for　the　Italian　National　Road　Authority　(ANAS)　is　presented.　A　typical　simply　supported　bridge　＂Viadotto　Serrone＂　in　Italy　was　chosen　as　case　study.　The　corresponding　finite　element　model　was　built　by　Sap2000　considering　some　critical　issues,　such　as　soil-structure　interaction,　plastic　hinge　assignment,　foundation　modeling　and　retrofitting　process　simulation.　In　order　to　find　out　the　most　critical　influential　factors　and　useful　regulations　which　can　be　adopted　as　the　guideline　of　this　retrofitting　technology,　the　influence　of　the　new　Italian　codes　on　the　mechanical　properties　of　different　types　of　bridge,　including　the　simply　supported　bridge　without　rehabilitation　and　integral　abutment　bridges　after　retrofitting,　were　investigated　using　finite　element　model.