40 katlı asimetrik betonarme bir binanın deprem performansının zaman tanım alanında doğrusal olmayan hesap yöntemi ile belirlenmesi
Determination of the performance analysis of an existing reinforced concrete building of 40 storey with an asymmetric floor plan using time history analysis
Yazar: TANER AKSOYLU
Danışman: DOÇ. DR. ABDULLAH NECMETTİN GÜNDÜZ
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / İnşaat Mühendisliği Ana Bilim Dalı / Yapı Mühendisliği Bilim Dalı
Derece: Yüksek Lisans, 2020
Konu: İnşaat Mühendisliği = Civil Engineering

Özet:
Deprem kuşağı üzerinde bulunan ülkemizde her gün irili ufaklı onlarca deprem meydana gelmektedir. Çoğunluğunu küçük şiddetli depremlerin oluşturduğu bu depremler, kimi zaman da büyük şiddetlerde meydana gelip can ve mal kaybına neden olmaktadır. 17 Ağustos 1999 Gölcük, 12 Kasım 1999 Düzce, 23 Ekim 2011 Van depremleri bunlara en büyük örneklerdir. 26 Eylül 2019'da meydana gelen 5.8 büyüklüğündeki Marmara Denizi depremi ve 21 Ocak 2020'de meydana gelen 6.8 büyüklüğündeki Elazığ depremi de mevcut yapıların deprem performanslarının değerlendirilmesini yeniden gündeme getirmiştir. 
18 Mart 2018 tarihinde yayınlanan ve 1 Ocak 2019 itibari ile yürürlüğe giren Türkiye Bina Deprem Yönetmeliği Bölüm 15'te Deprem Etkisi Altında Mevcut Bina Sistemlerinin Değerlendirilmesi ile ilgili kurallar verilmiştir. Bu çalışma kapsamında, verilen kurallar ve hesap esasları çerçevesinde, zaman tanım alanında doğrusal olmayan hesap yöntemi kullanılarak 40 katlı, asimetrik kat planına sahip betonarme bir yapının bina deprem performansı incelenmiştir.
Birinci bölümde, yürütülen tez çalışmasının amacı ve kapsamı hakkında bilgi verilmiştir. İkinci bölümde doğrusal olmayan davranış ve bu davranışın modellenmesi incelenmiştir. Doğrusal olmayan hesap yöntemleri ile ilgili bilgiler verilmiştir. Üçüncü Bölümde performans kavramından bahsedilmiş ve Türkiye Bina Deprem Yönetmeliğindeki yaklaşıma değinilmiştir. Dördüncü bölümde, deprem etkisi altındaki binalar için hesap esasları irdelenmiştir. Beşinci bölümde, zaman tanım alanında hesap için kullanılacak ivme kayıtlarının seçilmesi veya oluşturulması ve ölçeklendirme ile ilgili bilgiler verilmiştir.
Altıncı bölümde, tez çalışmasına konu olan mevcut binanın performans analizi bilgisayar programı yardımıyla yapılmıştır. Beton ve çelik malzemenin doğrusal olmayan davranışları modellenmiştir. Kesitler bu malzemeler ile oluşturulmuştur. Eleman açıklık uçlarına, kiriş ve kolonlar için yığılı plastik davranış modelince plastik mafsal atamaları yapılmıştır. Perdeler için ise yayılı plastik mafsal modeli kullanılmıştır. 
Zaman tanım alanında doğrusal olmayan analiz için, on bir adet gerçek deprem kaydı seçilerek ölçeklendirilmiştir. Analiz, deprem kayıtlarının birbirine dik iki doğrultuda yapıya etkitilmesi ile yapılmıştır. Deprem kayıtlarının kendi içlerinde doksan derece döndürülerek analizler tekrarlanmıştır. Analiz sonucunda kolon, kiriş ve perde elemanlar için plastik şekildeğiştirme ve plastik dönme değerleri incelenerek, hasar bölgelerindeki eleman sayılarına ulaşılmıştır.
Tez çalışmasının yedinci bölümünde, bir önceki bölümde yapılan analiz sonuçları irdelenmiş ve bu sonuçlardan yapılan çıkarımlar özetlenmiştir. Kolon ve perde elemanlarda plastik şekildeğiştirmeler çok az meydana gelmiştir. Sadece kirişlerde göçme bölgesine geçen elemanlar olmuştur. Bu elemanların oranları da göçmenin önlenmesi performans seviyesi sınırlarını aşmamıştır. Seçilen on bir deprem kaydı için, yapı performansı normal performans hedefi olarak belirlenen, göçmenin önlenmesi performans düzeyi olarak bulunmuştur.

Abstract:
As our country stands in an earthquake zone, there are tens of earthquakes with varying magnitudes happens every day. While most of these earthquakes are of small magnitudes, at times, high magnitude earthquakes happen, causing economic devastation as well as deaths. 17 August 1999 Gölcük, 12 November 1999 Düzce and 23 October 2001 Van earthquakes are examples of such. After the earthquakes at the near date of 26 September 2019 at the Marmara Sea and 21 January 2020 at Elazığ, the examination of the performances of the existing structures become a current issue.
In the Turkish Seismic Code for Building 2018 (TBDY 2018) Section 15, fundamentals of performance analysis of existing buildings have been given. In this study, the performance analysis of a 40 storey reinforced concrete building with an asymmetric floor plan has done according to regulations and basis that are given in the Turkish Seismic Code for Building 2018 (TBDY 2018).
On the first chapter, general information about the objective and the content of the thesis have been given. 
On the second chapter, non-linear behaviour and modeling of non-linear behavior was discussed. Non-linear behavior of construction material and large displacements were examined. Modeling of the non-linear behavior of a structure using plastic hinges was given. Non-linear analysis methods were examined. Time-history analysis and integration methods for the analysis were discussed.
On the third chapter, performance notion and approach of the Turkish Seismic Code for Building 2018 (TBDY 2018) on performance analysis has been given. Boundary conditions of plastic strain and plastic rotations for performance levels was given. 
On the fourth chapter, the fundamentals of analysis of buildings under earthquake load have been given. Steps for obtaining, target performance level for existing buildings were given. Irregular buildings and conditions of torsional irregularity as well as irregularity because of the offsets on floor plan  were examined.
On the fifth chapter, ground motion data selection or creation and scaling of ground motion data were investigated. Different approaches on ground motion data selection and some important criteria were given. Scaling methods for seismic acceleration records were given.
On the sixth chapter, performance analysis of the existing building that is the subject of this thesis has been done using the SAP200 computer program. Necessary information on the building has been given. The building is 134 meters' height, with 40 floor levels. The building is under use for housing purposes. Reinforced concrete material consists of C40 concrete and B420C steel rebars of various sizes. There are eleven grids on the long side and eight on the short side. Grid lengths differs and are given on the floor plan. At +26.80 and +53.60 elevations, sizes of some column's changes. Seismic parameters were obtained geographically from the website of the Disaster and Emergency Management Authority (AFAD). Design spectrum parameters and elastic design spectrum were obtained for intended ground motion levels and soil types at the location of the existing building from this website.
Seismic acceleration records were obtained from the Pacific Earthquake Engineering Research Center (PEER) database. Soil properties, distance from the nearest fault and seismic zone characteristics are considered on the selection. Scaling of the selected acceleration records were done using elastic design spectrum for the intended ground motion level, which was obtained from the website of Disaster and Emergency Management Authority (AFAD), as the target spectrum. Seismic acceleration record pairs were checked to ensure Turkish Seismic Code for Building 2018 (TBDY 2018) conditions. Non-linear material data for reinforced concrete materials were given to the program. Plastic hinge values were calculated for each cross section. Plastic hinges were assigned to both ends of the beams an columns to stimulate the non-linear behavior and measure plastic deformations at the given points. Fiber hinges were used at shear walls for obtaining more accurate results. Operational loads were defined for the beams, that encircle the corresponding slabs. For each elevation level, joints were constrained to stimulate continuous concrete slab behavior. Wind loads were affected to the building since the subject building is a high-rise building. 
The analysis model was affected by scaled acceleration record pairs in two perpendicular directions. Scaled acceleration record pairs were rotated 90° and affected again for the same earthquake. In total, 22 analyses have been done according to the Turkish Seismic Code for Building 2018 (TBDY 2018). For comparison purposes, another acceleration record that has vertical acceleration in it has been afflicted to model as well. But the change in the ratios of the elements on each damage zones was insignificant and did not effect the performance level. 
At the end of the chapter, the ratios of the elements on each damage zones were obtained and compared. The performance level of the building was evaluated by using these ratios. For columns and shear walls, damage zones at the ground floor were examined since high stress and strain levels can be accumulated. Shear forces were checked to determine whether brittle fractures occurred. Elements that were failed under shear forces were accepted to be in the collapse zone.
In the final chapter, the results of the performance analysis were discussed. As expected, most of the damage has occurred at the beams. Both columns and shear walls, plastic deformations mostly did not occur. At the ground floor and at the floors where column sizes changes, some damages could be observed. For each acceleration pair, performance levels were obtained for the targeted performance level of collapse prevention. However, the Turkish Seismic Code for Building 2018 (TBDY 2018) deems, structures at the collapse prevention performance level unfit for use.
In the suggestion part, shortcomings of the modeling were given. Since structures at the collapse prevention performance level are deemed unfit for use according to the Turkish Seismic Code for Building 2018 (TBDY 2018), strengthening of the building is suggested. As the Turkish Seismic Code for Building 2018 (TBDY 2018) is fairly new code, most of the existing buildings in Turkey are designed under previous seismic code. While the new code, introduces new criteria and conditions especially for high-rise buildings design, existing high-rise buildings that were designed under the previous seismic code should be evaluated.