15862

14162

كارشناسي ارشد

سازه

اصفهان : دانشگاه صنعتي اصفهان

1399

شانزده، 167ص. : مصور، جدول، نمودار

فرهاد بهنام فر

حسين تاجمير رياحي، پيام اسدي

1399/07/23

كتابنامه

مهندسي عمران

مهندسي عمران

1399/07/27

2643032

5 5 1 تأثير پيچش بر دريفت سازهها در تحليل 336 IDA 5 5 4 تأثير پيچش بر شتاب فروريزش سازههاي روي خاك 338 C 5 5 5 تاثير پيچش بر منحنيهاي شكنندگي و احتمال فروريزش سازههاي روي خاك 327 C فصل ششم خالصه نتايج و پيشنهادها 713 6 2 3 حداكثر خروج از مركزيت ممكن در انواع سازهها 813 6 2 2 تأثير پيچش بر رفتار فروريزش سازههاي روي خاك 318 C 6 2 1 تأثير پيچش بر رفتار فروريزش سازههاي روي خاك 319 D 6 2 4 مقايسه رفتار فروريزش سازهها بر روي دو نوع خاك مذكور 913 مراجع 343 پيوست 3 نتايج مربوط به سازههاي روي خاك 343 D چكيده التين 663 نه

366 Collapse Analysis of Torsional Moment Frame Structures Against Earthquake Yusef Mesr Habiby yusefdepp@yahoo com Date of Submission 2020 09 16 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Dr Farhad Behnamfar Farhad@cc iut ac irAbstractIn the present study the effect of torsion on the collapse behavior of steel moment frame structures is investigated For this purpose 4 7 and 10 story steel buildings with two types of soil C and D which are irregular in plan were designed by common softwares and it was observed that the eccentricity values in previous studies werehigher than possible in the reality and the maximum eccentricity in single moment frame systems if the membersare optimally designed considering the torsion is usually less than 10 Then the structures designed with logiceccentricity values were nonlinearly modeled and their collapse behavior under 11 consistent earthquake recordswas evaluated by incremental dynamic analysis IDA and spectral acceleration against the maximum floor driftcurves were calculated for each earthquakes Nonlinear modeling of members is done in OpenSees software andfor this purpose beams are modeled with nonlinear hinge elements concentrated on both ends and elastic elementbetween the two hinges and columns with BWH fiber element model The advantage of this type of modeling isthe involvement of the phenomenon of deterioration in beams and the interaction of two axis bending and axialforce in columns in the analysis Finally assuming the distribution of the log norm the fragility curve of eachstructure was plotted for different eccentricity values Using the results of analyzes the torsional irregularityeffects on the safety margin of collapse and the fragility curve of the structures were studied It was observed that this phenomenon can reduce the safety in the performance of the collapse of the structures With increasing torsion in buildings the collapse fragility curve retreats and as a result the acceleration of thecollapse as the probability of 50 decreases In addition as the torsion of the structure increases its marginalsafety margin decreases It should be noted that most of the changes occurred at the 15 eccentricity and thereare no drastic changes at the lower eccentricities so that the maximum reduction of the CMR values compared tothe non torsional one for eccentricities of 5 10 and 15 are 11 1 22 8 and 45 6 respectively whichall occur in the 10 story building on soil C The slope rate of this declining of safety margin is more remarkablein taller structures and the most reduction values in 4 7 and 10 story building are 8 7 23 7 and 45 6 respectively The results obtained in both types of C and D structures are similar and in the maximum eccentricityand the 10 story structure the most critical behavioral state always occurs The difference is that as the soil understructure becomes weaker the sections of members become heavier and the fragility curves are placed in front Itseems that as the stiffness of the structure decreases the torsional effect increases In the worst case the safetymargin of 10 story building suffering from 15 eccentricity ratio on the type C soil decreases up to 45 6 compared to the non torsional state while the reduction value in the same structure on soil D is 25 1 Note thatthe eccentricity of all floors of each structure was assumed to be same Therefore the significant effect of torsionon 7 and 10 story structures is somewhat exaggerated because the possibility of simultaneous occurrence of thesame eccenticity in all floors is low It should be noted that in this study soil structure interaction have beenneglected KeywordsCollapse analysis Torsional structure Incremental dynamic analysis Fragility curve Steel moment frame Probabilistic

فرهاد بهنام فر

حسين تاجمير رياحي، پيام اسدي