A Relative Reliability Approach For Direct Displacement-based Seismic Design Of Partially Prestressed Reinforced Concrete Frame Structures

Based on preliminary design method proposed by our research group, the relativereliability theory has been supplied and refined. DDBD method for multilayer framestructures and high-rise frame structures have been put forward. Determine the targetdisplacement and section bearing capacity equation in DDBD mothed proposed in thisstudy based on calculation results of24PPC frames, Influence factors of reliabilityhave been analysised by results of10PPC frames designed according to DDBDmethod, the availablity of DDBD method for structures based on relative reliability hasbeen proved, The Mode Pushover Analysis (MPA) results of2high-rise PPC frameswhich considered higher modes, proved the availablity of DDBD mothed for high-riseframe structures based on relative reliability. The chief conclusions of the paper are asfollows:①The values of target displacement of multilayer PPC frames. When thestructures are required7degree seismic fortificatio, the target displacement is=1/1399under frequenct earthquake performance objective, the target displacementis=1/490under medium earthquake performance objective, the target displacementis=1/155under rare earthquake performance objective. When the structures required8degree seismic fortificatio, the target displacement is=1/850under frequenctearthquake performance objective, the target displacement is=1/297under mediumearthquake performance objective, the target displacement is=1/109under rareearthquake performance objective.②The values of correction coefficient forsection bearing capacity equation inDDBD mothed based on relative reliability. In the first method,1=1.2.In the secondmethod,2=1.2under frequenct earthquake,2=0.62under medium earthquake,2=0.35under rare earthquake.③The reliability index of structures designed according to DDBD methodproposed in this article can not achieve the avarage reliability index, however there is agreat tendency of improvement than force-based method.④Structures designed according to DDBD method proposed in this article cancontrol design displacement effectively. DDBD method for high-rise frame structurescan consider higher mode effects effectively, though the modes have a little changeamong pushover analysis, it is reasonable to consider the modes remain unchanged before performance point under rare earthquake.