| The traditional design philosophy lacks of quantitative methods about collapse resistant capacity,repairable capacity and economic loss,which is“no damage under minor earthquake,repairable under moderate earthquake and no collapse under major earthquake”.Given the above,the seismic performance evaluation using component-performance-based methodology is presented in this paper.The problems of collapse resistant capacity,repairable capacity and economic loss in reinforced concrete?RC?frame structure are studied.The main research works and results of this thesis can be presented as follows.?1?In view of the shortcomings of Chinese codes in the deformation limits of RC components,the seismic performance evaluation of RC frame structure using component-performance-based methodology is put forward,and the deformation limits are presented for ductile RC frame structure,especially for Chinese codes.Moreover,the structural performance level is determined by the statistics of actual damaged components distribution.?2?The collapse resistant capacity,structural failure mechanism and damaged components distribution are compared under four different collapse criteria.It indicates that the side-way collapse mechanism can be found at one or several storeys when the structural dynamic instability occurs.Therefore,the side-way collapse can reflect the rule of actual structure collapse to a certain extent,and can be considered as the collapse criterion.?3?The collapse resistant capacity of 48 RC frame structures are discussed by incremental dynamic analysis under 22 pairs of earthquake records.It manifests that the collapse margin ratios of 40 RC frame structures conform to current Chinese codes are mainly distributed between 3.0 and 5.0.Moreover,the mean collapse probability under rare earthquake is 4.02%,and only the collapse probability of individual structure exceeds 10%,hence the goal of“no collapse under major earthquake”can be achieved.?4?The evaluation method of repairable capacity for RC frame structure using component-performance-based methodology is presented.The RC frame structure has to be demolished once one column deformation exceeds the ultimate deformation,and the residual inter-storey drift ratio can not surpass 1.5%.In addition,the repairability margin ratio?RMR?is introduced and the RMRs of 48 RC frame structures are studied.It can be found that the RMRs are mainly between 2.5 and 4.5.The average demolition probabilities under moderate,rare and very rare earthquake are 1.90%,16.22%and 56.75%respectively,therefore the requirement of“repairable under moderate earthquake”can be satisfied.However,the demolition risk is more remarkable than collapse risk,and the RC frame structures may be demolished beyond rare earthquake.?5?Earthquake loss evaluation of ductile RC frame using component-performance-based methodology is proposed.The influences of structure collapse and demolition are considered,and the earthquake loss is divided into the loss caused by structural components,nonstructural components and rugged components respectively.And the earthquake loss ratios of 48 RC frame structures are discussed.It can be demonstrated the expected annual earthquake loss ratios of 40 RC frame structures conform to current Chinese codes are mainly distributed between 1.0×10-3 and 2.0×10-3.The average earthquake loss ratios under minor,moderate,rare and very rare earthquake are 0.57%,3.56%,19.96%and 62.60%respectively,and the earthquake loss ratios under minor and moderate earthquake are mostly caused by repair cost of non-structural components.Moreover,the RC frame structure will lost its repairability in terms of economy beyond rare earthquake.?6?Bracing configuration of steel-brace RC frame using topology optimization based on truss-like material model is studied.Optimized bracing systems of entire structures and one-storey one-span structures are gained under different constraint conditions.It is found that bracing system of RC frame can be derived using topology optimization,and the bracing system based on truss-like model can resolve numerical instabilities like unshaped boundary and checkerboard phenomenon.And the reasonable bracing systems can be proposed according to engineering requirement.The optimized bracing system based on entire structure is more reasonable when some constraints do not need to be considered,like installing windows.Moreover,the optimized configurations of one-story one-span structure are more flexible to be adopted within the prescribed conditions when some constraints cannot be ignored.In addition,the X-brace based on one-story one-span structure is more favorable when?not exceeds 1.25,and V-brace is more advisable when?exceeds 1.5.?7?The structural stiffness,bearing capacity,ductility,collapse resistant capacity and expected earthquake loss of different bracing configurations are compared by structural mode analysis,static nonlinear analysis and dynamic nonlinear analysis.It can indicate that the optimized bracing system based on entire structure is most effective to enhance structural strength,stiffness,collapse resistant capacity and repairability.And expected earthquake loss can be reduced.Furthermore,optimized configurations of one-story one-span are more effective than other configurations within the prescribed conditions in general.Moreover,the brace buckling can decrease the favorable effect and aggravate the damage extent than the brace without buckling. |
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