بررسي عددي رفتار غيرخطي ديوارهاي برشي پيش‌ساخته‌ي بتني

Numerical Study of the Nonlinear Behavior of Concrete Precast Shear Walls

استفاده از سيستم ديوار برشي بتني پيش‌ساخته در ساختمان‌هاي بتني پيش‌ساخته با وجود داشتن مزيت‌هاي پيش‌ساختگي، به‌دليل كمبود ضوابط آيين‌نامه‌‌يي پيرامون طراحي لرزه‌‌يي اتصالات در آن‌ها با محدوديت‌هايي همراه است. بنابراين براي توسعه‌ي استفاده از ديوار‌هاي برشي بتني پيش‌ساخته، بررسي‌هاي بيشتري در مورد رفتار لرزه‌يي اتصالات آن‌ها مورد نياز است. در اين مطالعه، چند ديوار برشي بتني پيش‌ساخته با ارتفاعات مختلف مدل‌سازي و تاثير دو نوع اتصال افقي به‌كاررفته مابين پانل‌هاي ديوار برشي پيش‌ساخته (اتصال اسليو و اتصال ورق) بررسي شده است. در ادامه، مقايسه‌‌يي از نظر ميزان مقاومت، شكل‌پذيري، جذب انرژي و الگوي ترك‌خوردگي بين ديوارهاي مشابه در دو حالت يك‌پارچه و پيش‌ساخته تحت بارگذاري لرزه‌يي صورت گرفته است. نتايج نشان مي‌دهند كه با تقويت اتصالات ديوارهاي پيش‌ساخته مي‌توان رفتار ديوارهاي پيش‌ساخته را به ديوارهاي يك‌پارچه نزديك‌تر كرد. در اين ميان اتصال اسليو در مقايسه با اتصال ورق، رفتار بهتري نشان داده است.

Nowadays, with growing populations and the need for rapid methods of construction, the use of precast concrete structures is common. These structures have better quality in comparison with in-site ones. Past earthquakes have shown that damage to the precast concrete structure has occurred in their connections. So, the seismic behavior of a precast concrete structure depends significantly on the behavior of connections between the precast segments. Despite the advantages of precasting, using precast concrete shear walls is limited in low seismic regions, due to the lack of knowledge about this type of construction performance under seismic loading conditions. Therefore, the use of precast concrete shear walls needs further study on the seismic behavior of their connections. Due to the high cost of experimental studies, using comprehensive and efficient numerical methods that could predict the seismic behavior of this type of structure can be very effective. In this study, using the finite element software ABAQUS, several precast concrete shear walls with diffferent heights were modeled and the effect of horizontal connection types used between precast concrete shear wall panels (Sleeve & Plate Connectors) is investigated. Finally, a comparison in terms of strength, ductility and energy absorption between similar monolithic and precast walls under seismic loading was undetaken. The results indicate that precast concrete shear walls show lower resistance and initial stiffness in comparison with similar monolithic walls. The main difference between monolithic and prefabricated concrete systems is their connections, so, this difference in stiffness and ultimate strength can be assigned to precast concrete wall connections. Therefore, more attention should be paid to the design of precast concrete shear wall connections. Also, the strength and stiffness of precast walls can be improved by fortifying their connections. The sleeve connector shows better behavior in comparison with plate connectors. Ultimate displacement of precast walls was reduced with plate connections. This is because of the early concrete crushing failure due to an increase in panel rotation, which is due to further plate deformations in comparison with the sleeve. Although flexural cracks develop in monolithic walls, shear crack patterns are observed in precast walls.