Structural　over-strength　is　an　important　factor　for　structural　collapse　prevention　when　the　structures　suffer　major　earthquakes,　however,　it　isn＇t　included　in　our　current　Chinese　seismic　design　code,　and　the　seismic　design　specifications　for　structural　safety　calculations　are　based　on　structural　members,　with　no　more　consideration　on　global　carrying　capacity　of　the　whole　structure.　17　RC　frame　buildings　with　different　fortification　intensities　and　storeys　were　designed　according　to　the　current　Chinese　Codes.　These　structures　were　modeled　and　analyzed　in　the　platform　OpenSees.　By　comparison　of　the　quasi-static　test　data　for　RC　frame　structures　with　the　analytical　data　correspondingly,　the　OpenSees　models　were　verified　and　validated.　For　these　17　RC　frames,　structural　seismic　response　was　analyzed　by　nonlinear　dynamic　procedures　(NDP),　and　the　values　of　the　＇capacity＇　of　structural　overstrength　factors　and　their　variation　rules　with　structural　storeys　and　design　fortification　intensities　were　analyzed　and　derived.　It　is　shown　that　structural　ultimate　load　carrying　capacity　in　collapse　prevention　performance　level　can　be　estimated　by　structural　overstrength　factor　＇capacity＇.　For　RC　frames　designed　in　seismic　fortification　intensity　VI,　VII,　VIII,　structural　global　overstrength　factors　＇capacity＇　are　6,　4,　3　above　respectively,　and　the　minimum　value　agrees　with　the　value　3　given　in　NEHRP　recommended　provisions.　©,　2015,　Hunan　University.　All　right　reserved.