Deprem Giriş Enerjisi İle Spektral Hız Arasındaki İlişkinin İrdelenmesi

Deprem etkisine göre tasarım için önerilen enerji esaslı analiz yöntemleri sahip oldukları üstünlükler nedeniyle gün geçtikçe daha fazla ilgi görmektedir. Analizde depremin süresi ve frekans içeriğinin dikkate alınabiliyor olması bu tür yöntemlerin en önemli üstünlükleridir. Enerji esaslı analiz yöntemlerinin başarılı sonuç üretebilmesi için yapı sistemine giren deprem enerjisinin “doğru” tahmini önem taşımaktadır. Enerji denge denkleminin çözümüyle giren deprem enerjini elde etmek zahmetli bir işlem olduğundan, bu büyüklük literatürde genellikle eşdeğer spektral hız cinsinden ifade edilmektedir. Bu ilişkinin sadece sönümsüz sistemler için geçerli olacağı literatürde tartışılmaktadır. Bu bağlamda, yapısal sönümün yapıya aktarılan deprem enerjisi ile eşdeğer hız arasındaki ilişkiye olan etkisi bu çalışmada kanıtlanmıştır. Çok sayıda deprem kaydı ve farklı sönüm özellikleri için zaman tanım alanında analizler gerçekleştirilmiştir. Deprem kayıtlarının seçiminde kayma dalgası hızı (Vs30) ve kayıt türü (sıradan ve darbe etkili) değişkenleri dikkate alınmıştır. Gerçekleştirilen analizler sonucunda, yapıya aktarılan deprem enerjisi ile eşdeğer spektral hız arasındaki ilişkinin farklı sönüm özellikleri için aynı olmadığı görülmüştür. Mevcut ilişki için yeni katsayılar önerilmiştir.

Anahtar Kelimeler:

Giren enerji, spektral hız, enerji denge deklemi, enerji esaslı sismik tasarım

Evaluation of the Relation between Seismic Input Energy and Spectral Velocity

Energy based seismic design concept is getting attention owing to its advantages over the conventional methodologies. Particularly, the consideration of duration and frequency content of the earthquake record are chief superiority of the concept. For this original design procedure, accurate determination of seismic input energy is crucially important. Because of solving energy balance equation is a tedious job, the seismic input energy is determined in terms of equivalent velocity in the literature mostly. However, it was also shown that this relation is valid for only undamped systems. Therefore, this study aims to provide the nonsteady relation between seismic input energy and equivalent velocity for damped systems. Intensive response history analyses were performed by using plenty of earthquake records those were selected by considering the impulsive characteristics (ordinary and pulse-like) and shear wave velocity. It was found that the relation given in the literature for seismic input energy and spectral velocity relation is not true for damped systems. Dependently, it is proposed a set of coefficients considering structural damping properties to modify the existing relation.

Keywords:

Input energy, Spectral velocity, Energy balance equation, energy based seismic design,

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