Low-cost seismic base isolation using scrap tire pads (STP)

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2006

Öğrenci: BAYEZİD ÖZDEN

Danışman: AHMET TÜRER

Özet:

This thesis focuses on the experimental studies conducted on the development of low-cost seismic base isolation pads using scrap automobile tires. Seismic base isolation is a well-defined building protection system against earthquakes, on which numerous studies have been conducted. The majority of the previous studies focus on the performance improvement of the base isolation systems. However, this study aims at cost and weight reduction of seismic base isolation pads by recycling otherwise useless material: scrap tires. Elastomer-based isolators have been heavily studied and used for the last 25 years. Steel or fiber reinforcement inside the elastomer isolators provides high vertical stiffness, whereas rubber segments between reinforcement layers provide low horizontal stiffness for the seismic base isolation. Since 1960̕s, automobile tires have been produced by means of vulcanizing rubber with steel mesh in different forms which have a similar effect as the steel plates or fibers inside the conventional elastomer-based isolators. Therefore, rectangular shaped layers cut from tread sections of used tires and then piled on top of each other can function as an elastomeric bearing. Since the tires are being designed for friction, load transfer between scrap tire layers would be large enough to keep all layers intact. A minimal slip generated between the piled layers at high strain rates may even help to dissipate some extra energy. Axial compression, dynamic free vibration, static shear and shaking table tests have been conducted on Scrap Tire Pads (STP) prepared by using different tire brands for different number of layers and orientations. The results have shown that the average shear modulus of STPs change between 0.9MPa and 1.85MPa. At the end of the dynamic tests it has been noticed that the lateral stiffness of STPs can be simply adjusted by changing the number of