Farklı zemin türlerinin, yatay deprem ivmeleriyle beraber düşey deprem ivmelerine de maruz kalan perdeli çerçeveli binaların davranışlarına etkisi
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Tarih
2018
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Yayıncı
Kırıkkale Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Bu tez çalışmasının temel amacı, rijit mesnetli (FS) ve yapı-zemin etkileşimli (SSI) yapı modelleri kullanarak, farklı zemin türleri için çok katlı yarı sünek (perde + çerçeve) betonarme yapılarda düşey deprem hareketinin etkisini incelemektir. Bu kapsamda, 2007 Türk Deprem Yönetmeliği'ne göre tasarımı yapılmış 10 katlı betonarme yapılar dikkate alınmıştır. Maksimum düşey / yatay deprem ivmesi (V/H) oranları farklı olan üç deprem kaydına göre zaman tanım alanında doğrusal deprem analizleri yapılmıştır. Rijit mesnetli yapı, çubuk, kabuk ve plak sonlu eleman türleri kullanılarak yarı sünek olarak modellenmiştir. Yapı-zemin etkileşimli model için literatürde sıklıkla kullanılan direk metot kullanılmıştır. Yakın alan etkisi için zemin, temel boyutunun beş katı boyutlarında bir zemin ortamı tanımıyla solid bir eleman olarak ve yapı temeli ile bütünleşik şekilde modellenmiştir. Uzak alan etkisi ve ana kaya için ise, sırasıyla sönümleyici ve sabit mesnet tanımı yapılmıştır. Düşey deprem hareketinin etkisini belirlemek için, taban kesme kuvveti, taban devrilme momenti, taban eksenel kuvveti, tepe kat yatay ve düşey yer değiştirmesi değişkenleri incelenmiştir. Her iki modelleme türünde de (rijit mesnetli ve yapı-zemin etkileşimli), sadece yatay ile yatay + düşey yer hareketleri altında yapılan analizlerin sonuçları karşılaştırmalı olarak sunulmuştur. Yapılan bu analizler sonucu, zemin türünden bağımsız olarak düşey deprem hareketinin taban kesme kuvveti üzerinde etkisinin olmadığı (SSI ve FS modellerinin her ikisi için de) belirlenmiştir. Fakat SSI ile FS modelleri, değersel olarak karşılaştırıldığında SSI modelinin daha kritik sonuçlar verdiği görüldüğünden analizlerin SSI modeli üzerinden yapılmasının daha doğru olacağı belirtilmiştir. Tüm zemin türleri için iki modelden elde edilen devrilme momenti değerlerinin birbirine yakın olduğu fakat düşey deprem hareketinin analizlere katılmasının devrilme momentini önemli derecede arttırdığı belirlenmiştir. Bu durum her iki modelleme durumu için geçerli olmasına rağmen SSI modelinin dikkate alınması gerekmektedir. Beklenildiği gibi düşey deprem etkisi her iki modelleme durumunda da (FS ve SSI) taban kesme kuvvetini önemli derecede arttırmakta ve bu artış FS modelinde daha yüksek değerlere ulaşmaktadır. Bu sonuç, zemin ortamının yer değiştirmelere izin vererek eksenel kuvveti sönümlediğini göstermektedir. Tepe kat yatay yer değiştirme ile taban kesme kuvveti arasındaki doğrudan ilişkiye dayanarak, tepe kat yatay yer değiştirme değerlerine düşey deprem hareketinin bir etkisinin olmadığı tespit edilmiştir. Aynı şekilde tepe kat düşey yer değiştirme ile taban eksenel kuvveti arasındaki doğrudan ilişkiye dayanarak, tepe kat düşey yer değiştirme değerlerinde düşey deprem hareketinin etkisiyle büyük artışlar gözlenmiştir.
The main aim of the present study is to identify the effect of the vertical ground motion on semi-ductile high-rise reinforced concrete (R/C) structures, considering different soil types and by using structural models with fixed supports (FS) or with soil-structure interaction (SSI). In this sense, a high-rise semi-ductile in-service R/C structure that was designed according to the 2007 Turkish Seismic Code was utilized in the linear time-history (LTH) analyses. LTH analyses were conducted for three earthquake records with different vertical-to-horizontal maximum acceleration ratio (V/H). Frame, shell and plate finite elements were used to obtain a semi-ductile FS model with no soil media, whereas the Direct Method, commonly preferred in the literature, was used in SSI analyses. In the SSI model, the near soil field effect was defined with the help of a soil media with the dimensions about 5 times the dimensions of the mat foundation of the structure. The soil media was modeled as integrated with the mat foundation and as a solid element. For the far-field effect and the main bedrock, on the other hand, non-linear damper element and fixed-support definitions were realized. The base shear force, base overturning moment, base axial force, top-story lateral and vertical displacement values were examined to establish the influence of the vertical seismic motion on the structure and comparative conclusions were presented. The conducted analyses showed that in both SSI and FS models, the vertical earthquake motion did not influence the base shear force regardless of the soil type. However, the increase in the base-shear force obtained from the SSI model was observed to be higher than that from FS, so the SSI model was recommended to be used in the seismic analyses of structures. Similarly, no considerable increase in the overturning moment was observed both in the SSI and FS models. Nevertheless, the incorporation of the vertical earthquake motion to the analyses resulted in considerable increases in the values of the overturning moments in both types of models. Although similar conclusions were achieved from both types of models, the use of the SSI model is recommended over the FS owing to its various advantages. As expected, the base shear force values are affected to considerable degrees with the inclusion of the vertical ground motion and this increase reaches higher values in FS models. The lower increase in the SSI models is associated with the ability of the soil zone to absorb the vertical force. Depending on the direct relationship between the top-story horizontal displacement and the base shear force, the inclusion of the vertical seismic motion was found to have little influence on the top story horizontal displacement values. Related to the direct relationship between the top-story vertical displacement and the base axial force, the inclusion of the vertical seismic motion resulted in significant increases in the top-story vertical displacement values.
The main aim of the present study is to identify the effect of the vertical ground motion on semi-ductile high-rise reinforced concrete (R/C) structures, considering different soil types and by using structural models with fixed supports (FS) or with soil-structure interaction (SSI). In this sense, a high-rise semi-ductile in-service R/C structure that was designed according to the 2007 Turkish Seismic Code was utilized in the linear time-history (LTH) analyses. LTH analyses were conducted for three earthquake records with different vertical-to-horizontal maximum acceleration ratio (V/H). Frame, shell and plate finite elements were used to obtain a semi-ductile FS model with no soil media, whereas the Direct Method, commonly preferred in the literature, was used in SSI analyses. In the SSI model, the near soil field effect was defined with the help of a soil media with the dimensions about 5 times the dimensions of the mat foundation of the structure. The soil media was modeled as integrated with the mat foundation and as a solid element. For the far-field effect and the main bedrock, on the other hand, non-linear damper element and fixed-support definitions were realized. The base shear force, base overturning moment, base axial force, top-story lateral and vertical displacement values were examined to establish the influence of the vertical seismic motion on the structure and comparative conclusions were presented. The conducted analyses showed that in both SSI and FS models, the vertical earthquake motion did not influence the base shear force regardless of the soil type. However, the increase in the base-shear force obtained from the SSI model was observed to be higher than that from FS, so the SSI model was recommended to be used in the seismic analyses of structures. Similarly, no considerable increase in the overturning moment was observed both in the SSI and FS models. Nevertheless, the incorporation of the vertical earthquake motion to the analyses resulted in considerable increases in the values of the overturning moments in both types of models. Although similar conclusions were achieved from both types of models, the use of the SSI model is recommended over the FS owing to its various advantages. As expected, the base shear force values are affected to considerable degrees with the inclusion of the vertical ground motion and this increase reaches higher values in FS models. The lower increase in the SSI models is associated with the ability of the soil zone to absorb the vertical force. Depending on the direct relationship between the top-story horizontal displacement and the base shear force, the inclusion of the vertical seismic motion was found to have little influence on the top story horizontal displacement values. Related to the direct relationship between the top-story vertical displacement and the base axial force, the inclusion of the vertical seismic motion resulted in significant increases in the top-story vertical displacement values.
Açıklama
Anahtar Kelimeler
Deprem Mühendisliği, Earthquake Engineering ; İnşaat Mühendisliği, Civil Engineering, Asabiyet, Nervousness ; Modern toplum, Modern society ; Seçkinler, Elites ; Sosyal değişme, Social change ; İbn Haldun, İbn Haldun
