SİSMİK ZEMİN SIVILAŞMASINDA ZEMİN-YAPI-DEPREM- ETKİLEŞİMİ EFFECTS OF SOIL-STRUCTURE-EARTHQUAKE INTERACTION ON SEISMIC SOIL LIQUEFACTION TRIGGERING

OZET Bu bildiri kapsaminda ustyapi (bina) yukleri altindaki temel zeminlerinin sivilasma tetiklenme potansiyelinin belirlenmesine yonelik olarak gelistirilmis basitlestirilmis analiz yontemi tartisilacaktir. Uzerinde yapi bulunmayan, serbest saha kosullari altinda olarak da tanimlanan egimsiz zemin profillerinde deprem yukleri altinda sivilasma tetiklenme potansiyelinin belirlenmesine yonelik genel bir gorus birligi bulunmasina ragmen, ust yapi etkisi altindaki temel zeminlerinin sivilasma tetiklenme potansiyeli ile igili gorus ayriliklari bulunmaktadir. Bu calismada uc farkli saha zemin profili, iki farkli ustyapi kesiti ile, kombine edilerek 3-Boyutlu statik analizlere tabi tutulmustur. Bu analizlere ek olarak zemin ve ustyapinin dinamik tepkisinin belirlenmesine yonelik olarak, sonlu farklar yontemi ile calisan FLAC-3D yazilimi kullanilmis ve secilen 3 farkli deprem kaydi ile dinamik analizler gerceklestirilmistir. Gelistirilmis bu profillere ek olarak 1999 Kocaeli Depremi sonrasinda Adapazari'ndan elde edilmis vaka orneklerinin statik ve dinamik analizleri de bu calisma kapsamina dahil edilmstir. Yapilan tum analizler sonucunda ust yapinin sivilasma tetiklenme potansiyeli acisindan olumlu ve olumsuz yonde etkisi oldugu, sivilasma acisindan en kritik bolgelerin bina koseleri oldugu belirlenmistir. Sivilasma tetiklenme potansiyelinde ust yapinin etkisini belirlemek amaci ile CSRSSI,maksimum degeri tanimlanmis ve bu deger yapi-zemin etkilesimi parametreleri σ ve SA/PGA'ya bagli olarak hesaplanmistir. Anahtar Kelimeler: yapi - zemin etkilesimi, tekrarli gerilme orani, sivilasma ABSTRACT Although there exist some consensus regarding seismic soil liquefaction assessment of free field soil sites, estimating the liquefaction triggering potential beneath building foundations still stays as a controversial and difficult issue. Assessing liquefaction triggering potential under building foundations requires the estimation of cyclic and static stress state of the soil medium. As part of these ongoing studies, structural-induced shear stresses under building foundations subjected to cyclic loading are attempted to be estimated. For this purpose, series of 3-D numerical simulations including two different generic buildings resting on four different soil profiles have been performed. These generic cases have been shaken by three different earthquakes. In addition to these generic sites, static and dynamic analyses of case histories after 1999 KocaeliEartquake have been enclosed in this study. It is concluded that, structures can have either positive or negative effect from liquefaction triggering point of view and zones extending 0.2 width inside and 0.8 width outside of the edges are found to be relatively more critical from liquefaction triggering point of view as compared to the liquefaction potential of the zone in the vicinity of the foundation centerline. A new parameter CSRSSI,maximum has been defined to numerically define the effect of the structures on liquefaction triggering point of view. This parameter is being found to be a function of soil-stucture-interaction parameters σ and SA/PGA.