Geniş açıklıklı ve makas kirişli çelik bir alışveriş merkezi yapısının ilgili Türk standartları ile Avrupa standartları uyarınca ayrı ayrı boyutlandırılıp karşılaştırılması
Designing and comparing of a long span and truss girder steel shopping center structure according to related Turkish codes and related European codes
Yazar: ALİ DEMİR
Danışman: YRD. DOÇ. DR. BARLAS ÖZDEN ÇAĞLAYAN
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / İnşaat Mühendisliği Ana Bilim Dalı / Yapı Mühendisliği Bilim Dalı
Derece: Yüksek Lisans, 2012
Konu: İnşaat Mühendisliği = Civil Engineering
Dizin: Eurocode 3 = Eurocode 3 ; Eurocode 8 = Eurocode 8 ; Eurocode = Eurocode ; TS 498 = TS 498 ; TS 648 = TS 648 ; Yapı analizi = Structure analysis ; Yapı optimizasyonu = Structural optimization ; Yapı tasarımı = Building design ; Yapı çeliği = Structural steel ; Çelik konstrüksiyon = Steel construction

Özet:
Bu çalışma lisansüstü tezi olarak hazırlanmış olup, geniş açıklıklara sahip çelik bir alışveriş merkezi yapısının hem ilgili Avrupa Standartlarına hem de ilgili Türk Standartlarına uyularak boyutlandırılmasını kapsamaktadır. Bu tez çalışmasının amacı, farklı tasarım prensiplerini benimsemiş olan standartlar ve yönetmelikler uyarınca statik ve dinamik analizleri yapılan yapının yine bu standart ve yönetmelikler uyarınca tasarımının yapılması ve tasarım sonu yapı ağırlıklarının karşılaştırılmasıdır.Yapının boyutlandırılmasında kullanılan yönetmeliklere dair genel bakış birinci bölümde verilmiştir. Bunun yanında çeliğin yapısal malzeme olarak tarihteki gelişimi, buna bağlı olarak çelik yapıların giderek artan avantajları ile birlikte günümüzdeki tasarım gereksinimlerinden yine bu bölümde bahsedilmiştir.Çalışmanın ikinci bölümünde ise ele alınan çelik yapının geometrisine ve statik sistemine ait detaylar verilmiştir. Bunun yanında genel hesap esaslarından ve kabullerinden, hesapta kullanılan analiz programından bu bölümde bahsedilmiştir.Üçüncü ve dördüncü bölüm sırasıyla Avrupa Standartları ve Türk Standartları uyarınca yapılan boyutlandırma adımlarını içermektedir. Bu bölümlerde ilgili standartların genel tasarım prensipleri sunulmuştur. Yine yapı hesabında kullanılacak ölü ve hareketli yük değerleri ve bölge karakteristik değerleri üzerinden hesaplanan rüzgar ve deprem gibi hareketli etkiler bu bölümlerde detaylı olarak tanımlanmıştır. Betonarme döşeme mesnedi olarak teşkil edilen kat kirişleri tanımlanan yükler altında basit kiriş, sürekli kiriş ve kompozit kiriş olarak ayrı ayrı boyutlandırılmış ve bu üç teşkilin sonuçları ekonomi yönünden karşılaştırılmıştır. Kat kirişlerinin yanında kuşakların da düşey yükler ve rüzgar etkileri altında kesit tesirleri hesaplanmış ve tasarımları yapılmıştır.Yine üçüncü ve dördüncü bölümlerin devamında yapısal analizi ComoSYS adlı analiz ve tasarım programı ile yapılan yapının makas kirişlerinden ve kolonlarından örnek elemanlar seçilmiştir. Seçilen elemanlar her iki standart çözümü için aynı elemanlar olup, tasarımda esas alınacak kesit tesirleri analiz modelinden alınmış ve seçilen kesitler elle tahkik edilmiştir. Elle yapılan tahkik sonucu bulunan gerilme oranları, program tarafından bulunan gerilme oranları ile karşılaştırılmış ve sonuçların neredeyse aynı oldukları gösterilmiştir. Burada hem taşıyıcı eleman sınıflarından seçilen örneklerin detaylı tasarım hesaplarının gösterilmesi hem de tüm yapının boyutlandırılmasında kullanılan analiz ve tasarım programının doğru sonuçlar verdiğinin gösterilmesi amaçlanmıştır.Sonuç bölümü kapsamında ise farklı standartlar altında ayrı ayrı boyutlandırılan yapının iki duruma ait bir takım sonuç verileri sunulmuş, yapılar ağırlık yönünden karşılaştırılmış ve bu sonuçlar yorumlanmıştır.

Abstract:
Scope of this master degree thesis is designing of a steel structure according to related European and Turkish codes individually. This steel structure is designed as a shopping center which have long spans and moment resisting truss girders as a static system. Turkish codes belong to design of steel structures are based on allowable stress design. General principle of allowable stress design is obtaining a factor by reducing structural material resistance and increase actions on structures. By multiplying yield strength with this factor, allowable stress for design criteria can be determined. Subsequently structures are designed under concerned actions with allowable stress. On the other hand European codes, called Eurocode series, belong to design of steel structures are based on plastic design principles. According to these principles, yield strength of materials is used for design but actions on structures are multiplied by factors given in the related code. Detailed design steps of the building according to these codes and differences between the results can be find in this study. Aim of this study can be defined that comparing weight of structural elements and total weight of the structure as a result of two analysis and design process according to European and Turkish codes which have different principles, methods and rules. Besides European codes had been accepted and issued by Turkish Standards Institution as a reference codes. Thus, differences between national standards and newly issued standards are wanted to be shown by this study.In the first chapter, general information is given about development of steel production and steel structures in the history. Advantages of steel structures and useful properties of steel as a structural material are also mentioned in this part of the study. Besides, general information about usages and scopes of European codes and Turkish codes is given and evaluated in this chapter. For the design of the structure according to European codes, EN 1990, TS EN 1991-1-1, TS EN 1991-1-4, EN 1991-1-3, TS EN 1993-1-1 and TS EN 1998-1 standards are used. Scope of these standards are respectively "Basis of structural design", "Actions on structures - General actions", "Wind actions", "Snow actions", "Design of steel structures", "Design of structures for earthquake resistance". And Turkish standards used in the design are TS 498, TS 648, TEC 2007, İMO-02. Scope of these standards are respectively " Design values of loads for designing structural elements", " Design Rules of Steel Structures", "Turkish Earthquake Code", "Design Rules of Steel Structures by Civil Engineers Chamber".In the second chapter, geometric and static data of the structure, designed in this study, are presented. Structural type of the building is moment frames which are formed as truss girders in each two direction. Column bases are designed as pinned support in order not to transfer bending moment effects to reinforcement concrete columns. Plan dimensions of the building is 119 m x 92.3 m. In the long direction spans are equal to each other and lengths of these 7 spans are 17 meters. In the short direction 5 spans exist and lengths of the spans are variable from 14.3 meters to 21 meters. Concrete deck is provided at each three elevations of the building as a floor. Horizontal stability of the floors are also provided by these concrete decks. In the analysis model horizontal bracings are used instead of defining shell elements so as to obtain axial loads of the structural elements in plane. Besides, considered design principles and acceptances in order to provide fair and true comparison between two design model, are given in this part of the study.In the third chapter, detailed design process of the structure is presented according to the related European codes. As mentioned before, European codes belong to design of steel structures are based on plastic design principles and allow to use yield strength of the material for section design. However sections will be used in design, should be compact enough to reach yield strength without any local failures such as lateral buckling, torsional buckling and corrugation. So as to provide these conditions in general, related code (EN 1991-1,"Design of Steel Structures) restricts flange and web dimensions and gives classifications of sections. According to these classification, 4 class is defined for sections. Whenever designers prefer sections in class 1 and class 2, yield strength of the material can be used for the design, otherwise code reduces the limit strength and plastic design principle lose its advantage against allowable stress design. While designing a structure with the principles of Eurocode, another advantage is using plastic section modulus for design under bending moment effects.And also dead and live loads are defined so as to apply to floors of the building in the third chapter. And other loads and actions such as wind, temperature, snow and earthquake are defined by using characteristic parameters of the region. According to related code (EN 1990 - Basis of structural design) two types of combinations called ULS and SLS are required. ULS combinations are defined for ultimate limit state design. SLS combinations are defined for serviceability limit state design. As a part of design process, detailed calculations and section designs of floor beams and girts are given. Loads on these frames are combined according to uls and sls combination types and section forces are calculated. Floor beams are designed as simple beam, continuous beam and composite beam individually and a weight comparison is shown between these three situation. Calculations and designs of main structural elements are done by ComoSYS analysis and design software. Typical section design calculations are made and shown in this part for columns, truss top chord, truss bottom chord and truss diagonal elements in order to provide design examples in this study. Frame forces of these elements are taken from the analysis model. Design results are compared with ComoSYS design results and similarities between the results are shown. Finally inter-storey drift check, according to TS EN 1998-1, is given in a table.In the fourth chapter, detailed design process of the structure is presented according to the related Turkish codes and Turkish Earthquake Code. Designing of the structure is based on allowable stress design according to TS 648. While designing sections, static and dynamic loads are combined without any amplification factor and these combinations are also used for serviceability criteria. Inconvenient stresses in the sections can be compared with allowable stress in order to design the section. Allowable stress value is obtained by multiplying yield strength of the material with the factor 0,6. In TEC 2007 flange and web dimensions of the sections are restricted for normal ductility and high ductility situations. Dead loads, live loads wind loads and snow loads are obtained from TS 498. For dynamic analysis of the structure, elastic response spectrum graphic defined belong to region of the building is taken from Turkish Earthquake Code. Floor beams are designed as a simple beam, continuous beam and composite beam individually and a weight comparison is shown between these three situation. Calculations and designs of main structural elements are done by ComoSYS analysis and design software. Typical section design calculations are also made and shown in this part for columns, truss top chord, truss bottom chord and truss diagonal elements in order to provide design examples in this study. Frame forces of these elements are taken from the analysis model. Design results are compared with ComoSYS design results and similarities between the results are shown. Finally inter-storey drift check according to TEC is given in a table.As a result, dynamic analysis results of the structure, concerned in this study, are shown as total shear forces and periods of the structures which are calculated by using different elastic response spectrum graphics belong to different earthquake codes. As mentioned before, main idea of this study is to compare total weights of the buildings which are designed according to two different design standards. In order to provide fair and true comparison, design ratios of structural elements are limited. Average design ratios of all type structural elements are kept between 0.9 and 1 for each two design models. Average design ratios of structural elements for two design models are given in a table in this chapter. In the final part of the study, total weight of the primary elements and total weight of the structure are given in a table with a comparison between buildings designed under Turkish codes and European codes. As shown in the table, the structure which is designed according to Turkish standards is %27 heavier than the structure which is designed according to European codes. This value is variable for structural element types and % 20 for columns, % 21 for truss diagonal elements, % 35 for truss bottom chords and % 40 for truss top chords. According to the European codes design rules, defining actions on structures, load combinations and designing steps are more complex than Turkish Standards, but design according to the European codes gives more economical results.