Research On One Improved Performance-based Evalua-Tion System And Deformation Limits Of SRC Component

The core concept of the performance-based seismic theory is to quantify the possible loss of the building structures at different hazard levels.Performance-based seismic design is based on evaluation of seismic performance.Its essence is the cycle of "design ? evaluation ? op-timization design ? reassessment".The key issue to the process is the setting of performance objectives and the criteria of performance evaluation.The traditional structural design method is a "preposition" design method which expected that the design results that meet the specified performance goals can be obtained by pre-derivation based on multiple assumptions.Whether or not the performance capability can meet the performance goals is worthy of discussion.On the contrary,the performance-based seismic design method is essentially a "postposition" eval-uation method.This method focus on whether the design result can pass the performance eval-uation rather than the method engineer uses to obtain the design result.Mature classification systems of structural performance level had been established through the relevant researches around the world.Moreover,seismic performance limits of RC struc-tural components had been obtained by our team and applied in the performance analysis of high rise buildings beyond code specification,however,there is still no further research on the relationship between structural performance and component performance.Although SRC com-ponents are commonly used in high-rise building structures,here is still a lack of systematic research on the performance of SRC components around the world,which limits the application of component performance research results.Therefore,this project mainly focuses on quanti-fying the correlation criteria between structural performance and component performance and the seismic performance of SRC components in the following aspects:(1)A seismic performance evaluation method based on statistical distribution is proposed.In this method,components are divided into key components,common components and sec-ondary components according to the importance degree or the individualized needs of the owner,and the relationship criteria between the structural performance level and the quantitative dis-tribution of the damage performance of the three types of components are established.Statis-tical distribution rules of structural performance levels under multiple excitations of assigned earthquake are obtained,and the probability evaluation results of seismic performance of the structure are further obtained.(2)The damage performance of the SRC components is classified into seven levels,namely,intact(C-1),light damaged(C-2),light and medium damage(C-3),medium damage(C-4),relatively serious damage(C-5),severe damage(C-6)and failure(C-7),with the corre-sponding to 6 target performance level limits,including PYield?PLevel1?PLimited?PLevel2?PLevel3 and PUltimate?Specifically,PLimited =(PLevel1 + PLevel2)/2.Base on the systematic analysis and research,the macro-damage characteristics and the material strain limits of the components corresponding to different performance levels are given,and the drift angle is cho-sen as the deformation index.Quantification principle of SRC component performance is pro-posed based on the material strain damage theory.(3)The SRC component deformation index limit analysis software is developed based on ABAQUS,which are 1)Plastic damage constitutive model generation program "CreatMate-rial.exe",2)Preprocessor "CreatINP.exe",3)Postprocessor "PostABAQUS.exe".The SRC component performance quantification criteria of(2)are embedded in the post-process pro-gram,which realizes the automatic processing of the calculation and analysis of the limit value of the SRC component deformation performance.(4)Through systematic comparison and verification of tests,the reliability and applicabil-ity of simulation methods are proved.Using the principle of simulation test,loading tests were performed on the ABAQUS platform and a total of 3840 SRC beam components,4860 I-shaped steel SRC columns and 6246 cross-shaped steel SRC columns were created.Parametric study of simulation test results are analyzed systematically.(5)Based on the study of the cross-section deformation features,it was found that different failure modes show obviously different distributions in the cross-section drift of the test speci-mens.It was observed that the deformation of the cross-section angle related to the bending deformation has a feature that gradually accumulates along the longitudinal direction of the component,while the inter-section shear-slip deformation associated with the shear defor-mation does not exhibit this property.Based on this feature,the proportion of shear deformation when component fails is selected as the criterion and a new method for classifying the failure mode of SRC component is proposed.(6)Based on the analysis of failure modes,the judgment criteria for different types of SRC beams and columns are proposed respectively using bending shear ratio and nominal shear stress level.Combined with the parameter study results,it is found that the failure mode of the component is the main reason for the linear distribution of the plastic deformation per-formance points with different parameters.This finding also provides a basis for obtaining the formulas of the component plastic deformation performance index limit through the stepwise linear regression analysis.(7)Through the linear regression analysis method and step-by-step screening regression strategy,the deformation performance index limit regression formulas for SRC beam,I-shaped steel SRC column and cross-shaped steel SRC column member were established for three dif-ferent failure modes:bending failure,bending shear failure and shear failure.And the reliability of simulation analysis results are verified through existing experiments.The research results provide a solid basis for the application of performance-based seismic evaluation in the struc-ture using SRC components.