Deprem Bölgesinde Bulunan Mevcut Bir Tank Yapısının Geoteknik Değerlendirmesi

Bu çalışma TBDY 2018, uluslararası standartları ve literatürdeki çalışmaları esas alarak deprem bölgesinde bulunan mevcut bir tank yapısının deprem yükleri altında geoteknik değerlendirmesini sunmaktadır. Sahada sıvılaşma potansiyeli bulunması ve kayma mukavemeti düşük 35 m'den kalın kil tabakalarının mevcut olması sebebiyle zaman tanım alanında doğrusal olmayan boşluk suyu basıncı modelleri kullanılarak ve kullanılmadan sahaya özel zemin davranış analizleri ayrı ayrı gerçekleştirilmiştir. Zemin yumuşaması ve sıvılaşmasının doğal bir izolatör gibi davranarak yüzey ivmelerini ciddi oranda sönümlediği gözlemlenmiş, ancak serbest sahada yüksek mertebelerde yanal yer değiştirmelere (2.0-2.3 m) ve düşey oturmalara (58-128 cm) sebebiyet verdiği tahmin edilmiştir. Tank yapısı temelinde oluşacak farklı oturmanın yaklaşık en fazla 70-80 cm, en düşük ise 5-10 cm mertebelerinde olduğu tahmin edilmekte ve boru bağlantılarında bu yer değiştirme farkının göz önünde bulundurulması önerilmektedir. Üst yapıdan gelecek olan atalet (ilave deprem) yükleri altında tank yapısı tabanında ve geogritli dolgu altında taşıma gücü ve tabanda kayma kontrolleri yapılmış ve güvenli bulunmuştur.

Anahtar Kelimeler:

Sismik analiz, tank yapıları, sıvılaşma, sahaya özel yer tepki analizleri, TBDY 2018

Geotechnical Evaluation of an Existing Tank Structure Located in a Seismic Zone

This study presents the geotechnical evaluation of an existing tank structure under earthquake loads, based on TBDY 2018, international standards, and the published models in the literature. Due to the presence of liquefaction potential and clay layers thicker than 35 m with low shear strength in the field, non-linear site-specific analyses were performed in the time domain with and without pore pressure models. Soil softening and liquefaction act as a natural isolator, damping surface accelerations significantly, but they have caused high lateral displacements (2.0-2.3 m) and vertical settlements (58-128 cm) in the free field. It is estimated that the differential settlement at the tank structure is approximately 70-80 cm at the maximum and 5-10 cm at the lowest that is needed to be considered in pipe connections with the tank at the site. Under the additional earthquake loads from the superstructure, the bearing capacity and sliding control on the bottom of the tank structure and under the fill reinforced with geogrid were found to be safe.

Keywords:

seismic analysis, tank structures, liquefaction, site-specific ground response analysis, TBDY (Turkish Earthquake Resistant Building Design Regulations) 2018,

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