مدل‌سازي رفتار لرزه يي و برآورد خسارت ديوارهاي گهواره‌يي بتني تحت بار زلزله

Numerical modeling of seismic response and damage estimation of concrete rocking walls under seismic loading

استفاده از ديوارهاي گهواره‌يي به‌عنوان يك جايگزين در جهت رفع برخي نواقص لرزه‌يي ديوارهاي برشي همانند خسارت چشم‌گير در پايه و تغييرمكان ماندگار، با استقبال گسترده‌يي روبرو شده است. علي‌رغم كارهاي آزمايشگاهي مختلف درخصوص عملكرد لرزه‌يي ديوارهاي گهواره‌يي، تاكنون مدلي تحليلي، كه رفتار غيرخطي آن را تحت زلزله پيش‌بيني و ميزان خسارت در سطح ديوار را مشخص كند، ارائه نشده است. هدف از پژوهش حاضر، ارائه‌ي روشي كاربردي جهت مدل‌سازي و تخمين خسارت ديوارهاي گهواره‌يي با كابل‌هاي پس‌كشيده تحت بارگذاري لرزه‌يي است. بدين منظور جهت مدل‌سازي ديوار گهواره‌يي از نرم‌افزارPerform3D استفاده شده است. جهت اطمينان از صحت مدل‌سازي، نتايج آزمايشگاهي با نتايج تحليلي مقايسه شده‌اند، كه مدل پيشنهادي به‌خوبي مي‌تواند رفتار غيرخطي ديوار گهواره‌يي را تحت زلزله پيش‌بيني كند. همچنين با استفاده از شاخص خرابي، ميزان خسارت وارده به ديوار با بهره‌گيري از نتايج مدل‌سازي برآورد شده است، كه مقايسه‌ي بين خرابي برآورد شده و ديوار آزمايشگاهي انطباق بالايي را نشان داده است.

Application of self-centering rocking walls is now widely accepted as a viable alternative to removal of some of the common seismic defects of conventional shear walls including residual drift and significant damage to the base of walls. Despite the different experimental studies on the seismic performance of rocking walls, few numerical models have been developed to predict the seismic response and damage extent of these walls under seismic loading. The main objective of this study was to present a practical method for numerical modeling and damage estimation for nonlinear behavior of post-tensioned (PT) concrete rocking walls when exposed to earthquake excitations. To this end, PERFORM 3D software was utilized to model self-centering rocking walls. The walls were subjected to a set of seven spectrum compatible ground motions at different intensity levels. To ensure the accuracy of the modeling, the numerical results of the nonlinear analysis were compared with the experimental results, and the results showed that the developed model could predict the behavior of the wall during all ground motions with acceptable accuracy. Moreover, in this study, a damage index was employed to estimate the extent of damage in the developed numerical model. Good agreement between the observed damage in the shake table tests and estimated damage in the developed model was observed. The results of this study indicated that the method for modeling the seismic behavior of the rocking wall could appropriately predict the response and damage extent of these walls under earthquake loading.