بررسي رفتار استاتيكي غير خطي و ارائه مدل غير خطي معادل براي اتصالات تير-ستون بتن مسلح

چكيده انگليسي :

199 Study of Non Linear Static Behavior and Equivalent Non Linear Model of Reinforced Concrete Beam Column Joints Morteza Omidi m omidi@cv iut ac ir Date of Submission April 6 2011 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisors Dr Farhad Behnamfar farhad@cc iut ac ir Adviser Dr Morteza Madhkhan madhkhan@cc iut ac ir AbstractIn reinforced concrete structures the beam column joints are the key elements in determiningstructural behavior against various loads A quick look at damage caused by past earthquakesindicates that in most cases the destruction of reinforced concrete structures is due to shortcomingin the joint zone while the other structural components have suffered little or no damage Thisresearch is timely because a large number of reinforced beam column joints with insufficientstrength or deformation capacity are in use today in seismic regions placing many structures andpeople at risk in the event of a major earthquake Considering this fact the need for more accurateassessment of the structural capacity of concrete components in seismic retrofit projects is felt Butto date behavior evaluation criteria for some of structural components such as reinforced concretebeam column joints is still based on engineering judgments and no coherent and comprehensiveanalytical and experimental data exist The need to do research in this field seems to be proper andis seriously required In this thesis the main purpose is the review and evaluation of nonlinear behavior of interiorreinforced concrete beam column joints in order to more accurately assessing its structural capacityand also providing an analytical model to simulate joint response and its impact on overallstructural behavior For this purpose three basic experimental specimens A M Z 4 B01 and D07tested by different researchers have been selected and then by changing shear demand of the jointsten new analytical specimens were defined The modeling of joints using ANSYS software isdescribed and to evaluate the accuracy of nonlinear analysis results they are compared withexperimental results showing good agreement The impact of behavior and stiffness of joint panel on overall response of basic joints are alsostudied To evaluate the performance of these joints the impact of various parameters such ascolumn axial load ratio joint shear demand ratio and transverse reinforcement details areinvestigated and in each case the relevant are presented The moment rotation curves obtained fromfinite element analysis of joints studied in specific groups are classified and the joint shear strain atthe corresponding strength is compared with those mentioned in seismic assessment instructionssuch as FEMA356 2000 and ASCE SEI41 06 2006 The finite element analysis results of studiedspecimens showed that the above guidelines provide a conservative assessment of joint shear strainat the related strength for interior joints with conforming transverse reinforcement details and jointshear ratio less than 1 5 and in contrast provided a non conservative assessment of this parameterfor interior joints with joint shear demand greater than or equal to 1 5 These guidelines provide aconservative or occasionally non conservative assessment of joint shear strain at the peak strengthfor joints with nonconforming transverse reinforcement details depending on the hoops spacingwithin the flexural plastic hinge region and within the joint axial load ratio and joint shear demand According to the results and considering the impact of parameters influencing the behavior ofjoints suggestions for determining the joint shear strain at the peak strength are presented Also stiffness models proposed by these guidelines are evaluated The results showed that these modelsprovide sometimes a non conservative assessment of initial stiffness of the joints depending onjoint shear demand ratio and column axial load In the last part of this thesis a pra

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بررسي رفتار استاتيكي غير خطي و ارائه مدل غير خطي معادل براي اتصالات تير-ستون بتن مسلح

ارزيابي لرزه اي , مدل اجزاء محدود , مدل تحليلي , شرايط آرماتور گذاري عرضي , سختي اتصال