Çelik yüksek bir binanın TBDY-2018`e göre tasarımı

Abstract

Yüksek lisans tezi olarak sunulan bu çalışmada 42 katlı çelik bir binanın Türkiya Bina Deprem Yönetmeliği (TBDY) ve Çelik Yapıların Tasarım, Hesap ve Yapımına Dair Esaslar (ÇYTHYE) yönetmeliğine göre tasarımı ve gerekli yapısal kontrolleri yapılmıştır. Yüksek bina olarak tanımlanan yapı, TBDY uyarınca yüksek binalar için tasarımda uygulanması gereken özel kurallar göz önünde bulundurularak tasarlanmıştır.Çalışma toplam 5 bölümden oluşmaktadır. İlk bölümde yüksek binaların gelişim sürecine ve TBDY'de yüksek binalar hakkında getirilen uygulamalara değinilmiştir.Çalışmanın ikinci bölümünde, tasarımı yapılacak olan bina hakkında genel bilgiler verilmiştir. Bina geometrisi ve bina taşıyıcı sistemi bu bölümde anlatılmaktadır. Afet ve Acil Durum Yönetimi Başkanlığı (AFAD) web sitesinden Türkiye Deprem Tehlike Haritası (TDTH) kullanılarak binanın bulunduğu koordinatlara ve zemin koşullarına bağlı olarak her bir deprem düzeyi için harita spektral ivme katsayıları elde edilmiş ve deprem hesabında kullanılacak olan tasarım spektrum grafikleri üretilmiştir. TBDY'ye göre bina performans hedefleri ve tasarım/değerlendirme yaklaşımı da yine bu bölümde verilmiştir.Üçüncü bölümde, yapıya etkiyen sabit ve hareketli yükler verilmiştir. Eurocode1-4 ve İstanbul Yüksek Binalar Rüzgâr Yönetmeliği (IYBRY) uyarınca yapıya etkiyen rüzgâr yükleri hesaplanmış ve rüzgâr etkisi altında binanın konfor tahkikleri yapılmıştır. Yüksek bina tasarımının I. aşamasında (ön tasarımda) kullanılacak olan DD-2 düzeyinde yapıya etkiyen azaltılmış deprem yükleri, taşıyıcı sistem davranış katsayısı ve dayanım fazlalığı katsayısı, yine bu bölümde incelenmiştir.Dördüncü bölüm deprem etkisi altında yüksek bina tasarımına değinmektedir. TBDY'ye göre yüksek binaların tasarımı üç aşamada yapılacaktır. I. tasarım aşamasında, DD-2 deprem yer hareketi düzeyinde dayanıma göre tasarım yaklaşımı ile Kontrollü Hasar (KH) performans hedefini sağlayacak şekilde bir ön tasarım yapılmıştır. II. Tasarım aşamasında, ön tasarımı yapılmış olan yüksek binanın DD-4 deprem yer hareketi altında Kesintisiz Kullanım (KK) performans hedefini sağlamak üzere, dayanıma göre tasarım yaklaşımı ile performans değerlendirmesi yapılmıştır. Tasarım aşaması III'te ise ilk iki aşaması tamamlanmış olan yüksek binanın DD-1 deprem yer hareketi altında Göçmenin Önlenmesi (GÖ) performans hedefini sağlamak üzere şekil değiştirmeye göre değerlendirme ve tasarım yaklaşımı ile performans analizi yapılmıştır.Son bölümde çalışmada elde edilen sonuçlar irdelenmiş ve öneriler verilmiştir.

In this study, which was presented as a master thesis, the design and necessary structural controls of a 42-storey steel building were made according to the Turkish Building Seismic Code (TBDY) and the Design, Calculation and Construction Principles of the Steel Structures (ÇYTHYE). The building, which is defined as a high-rise building, has been designed considering the principles of TBSC which should be applied in the design for high-rise buildings. Wind loads, which play an active role in the design of high-rise buildings, are also taken into consideration in the calculations as described in the TS-EN 1991-1-4 code and the comfort assessments of the structure under the effects of wind have been made. Structural system modeling, load definitions and structural analyzes were performed with the help of ETABS 2016 v16.2.1 finite element program. In addition he strength checks of the structural system elements were made with ferit.exe application made by Ferit Ömerbeyoğlu (M.Sc.), which calculates the cross-section in accordance with the ÇYTHYE and TBDY.The thesis composed of 5 chapters. In the first chapter, the development process of high-rise buildings and the applications about high-rise buildings in the TBDY were discussed. Also this chapter gives an introduction to the aims and objectives of the master thesis. As stated in Section 13 of the TBDY, high-rise building design is carried out in three stages. In the first design phase, a preliminary design has been made in order to achieve the Life Safety (LS) performance target by using the Strength Based Design (SBD) approach at the standard earthquake ground motion level DD-2 earthquake ground motion level. The second design phase consists the Strength Based Design (SBD) to achieve the Immediate Occupancy (IO) performance target under the DD-4 earthquake ground motion, the minimum earthquake ground motion level of the pre-designed high-rise building. In the design phase three, analysis whose first two phases were completed was performed with the Performance Based Design (PBD) approach in order to achieve the performance goal of Collapse Preventation (CP) under the earthquake ground motion DD-1, which is the disaster scenario of the high-rise building.The second chapter covers general information about the building to be designed. The building geometry is considered to be square. Edge lengths of the building are 34 m and the center of the building is designed empty. The gross floor area is 900 m2. The building carrier system is formed by the use of moment resisting steel frames with concentrically braced steel frames. Floor slabs consist of reinforced concrete floor system on trapezoidal sheet metal plates supported on steel beams. The building is thought to be used as a office building. Mapped acceleration parameters were obtained by using Turkey Earthquake Hazard Map (TDTH) from the web site of Disaster and Emergency Management Authority (AFAD) based on the coordinates of the building and the ground conditions. Manufactured to the design spectrum graphics to be used in seismic analysis. Building performance targets and design&evaluation approach according to TBDY are also given in this section. Finally, the structural system was checked for irregularity and the section was terminated. There were no irregularities in the structural system that would affect the design.The third chapter covers the dead and live loads on the structure. The live loads acting on the floor slabs were calculated using TS 498. The office building have 5 kN/m2 of live loads in the floor slabs and 2 kN/m2 of live load in the roof slab. Snow loads on the roof are calculated according to TS-EN 1991-1-3. According to ÇYTHYE, the notional loads expressing the geometric preliminary defects were effected as horizontal loads to the structure in the order of 0.003 of the vertical loads in each floor plane. These loads could be defined automatically with the ETABS program. Moreover, the self-weight of the structure is also spontaneously calculated by the ETABS program, too. Super dead loads of 2 kN/m2 was applied to floor slabs and super dead loads of 1.4 kN/m2 to the roof slab for the non-structural elements on the building. The wind loads on the structure have been calculated and the comfort checks of the building under the influence of wind have been made based on TS-EN 1991-1-4 and Istanbul High-Rise Buildings Wind Regulation (IYBRY). Furthermore, the peak acceleration and displacement of the building under the wind was controlled by considering the limit values given in AISC 360-10 codes. This chapter also provides the reduced earthquake loads, structural system behavior coefficient and the over strength factor which affect the structure at the DD-2 level to be used in the first stage of the high building design (pre-design). The building system behavior coefficient and strength excess coefficient of the building are determined as R = 6 and D = 2.5, respectively, according to TBDY Table 4.1. In the calculation of earthquake loads affecting the structure, modal response spectrum analysis method was used. In the modal response spectrum analysis method, 17 basic modes were considered in order to achieve 95% mass participation ratio in each direction as indicated in the TBDY. The effect of vertical earthquake is considered by adding the dead load in load combinations by providing the conditions given in accordance with TBDY.The fourth chapter focus on the seismic design of high-rise building. The design of high-rise buildings should be done in three stages as reported by TBDY. In the first design phase, a preliminary design was made according to the design approach in terms of DD-2 earthquake ground motion with respect to the Life Safety (LS) design. The interstorey drift and second order effects of the building were checked with the calculated earthquake loads. Then, as an example, each frame element (moment-resisting frame beam, brace, concentrically brace frame and column) strength tests were performed according to the ÇYTHYE and so the preliminary design was completed. In addition, DD-4 earthquake ground motion, which is the minimum earthquake level, was controlled by DGT approach in the second design stage. At this stage, the damping ratio was considered as 2.5%. parameters such as response modification coefficient (R), over-strength factor (D) and building importance coefficient (I) are taken into account as 1.0 in the calculation of earthquake loads. The material strengths to be used in the strength calculation of the elements are considered as the expected (average) yield. As a result, the second design stage was completed by controlling the demand capacity ratios of the structural system elements under the loads acting on the structure. This ratio was 1.5 for the ductile behavior and 0.7 for non-ductile behavior, acoording to the TBDY. Finally, the third design stage covers the non-linear time history analysis of the building under the DD-1 earthquake ground motion, which is called the disaster scenario. In this design stage, the damping ratio of the structural system is considered as 2.5%. Material strengths were determined as expected (average) yield, too. The nonlinear behavior of the structure is modeled with plastic hinges defined to the structural system elements. A lumped plastic hinge model is defined on the ends of the moment resisting frames and centered on the middle of the brace members, and a fiber plastic hinge model on the column ends. Moreover, according to TBDY, it is recomended that at least 11 earthquake records should be used in the non-linear time history analysis. It is also stated that the selection of these earthquake records should be made considering magnitudes, fault distances, fault types and soil class compatible with the earthquake ground motion. Pacific Earthquake Engineering Reaserch Center (PEER) database was used in the selection of earthquake records. The selected earthquake records were scaled in accordance with the earthquake ground motion of the design with the simple scaling method specified in TBDY. Before the nonlinear earthquake calculation of each record, the vertical static loads acting on the structure were applied incrementally to the structural system and the nonlinear static calculation was performed. The internal forces and deformations obtained as a result of this calculation were used as initial values in the horizontal earthquake calculation. The deformation demands to be evaluated in elements with ductile behavior as a result of the nonlinear time history analyzes were calculated by averaging the largest absolute value of the results obtained from each of the analyzes. And it has been shown to be below the limits for the respective performance levels. So that, nonlinear deformations occurring in the building structural system have been developed to provide the HR performance level. Finally, the third stage of the performance assessment was completed with relative floor shift control. The average inter-storey drift ratio obtained from 11 earthquake records taken at each storey should not exceed 0.03 as a result of the nonlinear calculation made in accordance with the TBDY. Furthermore, the largest relative inter-storey drift ratio from a single earthquake record should be less than 0.045.In the final chapter, the results of the study are discussed, and recommendations are presented. As a result of the nonlinear analysis, under the effects of DD-1 earthquake ground motion, it was observed that nonlinear behavior occured in the brace members of the concentrically braced frames, there was very little plastic deformation in the moment resisting frame beams and there was no plastic deformation in the columns. The minimum seismic load condition used in the preliminary design was found to be effective in sesimic design. As the wind effects are met with linear behavior of the elements in high building design, it has been found to be highly effective in the selection and sizing of the structural system.