Betonarme Yüksek Binalarda Yangın Güvenliği Ve Yangın Senaryoları Üzerinde İncelemeler

Abstract

Ülkemizde ve özellikle İstanbul da nüfusun artışı, hızlı kentleşme, ticari ve iktisadi birimlerin ihtiyaçları gibi nedenlerden ötürü hızla artan yüksek katlı binalar sosyal kültürel ekonomik ve teknik bağlamlarda çeşitli sonuçlar doğurmaktadır. Bu bakımdan yapı sektörünün konusu olan yapı malzemesi ve teknolojisi alanında kaydedilen bilimsel ve teknik gelişmeler yapı sektörünü hızlandırmakta ve yüksek katlı yapıların inşasını kolaylaştırmaktadır. Bu durum beraberinde mimari ve teknik anlamda karakteristik problemlere ve bunların özel çözüm yollarına ihtiyaç duyduğu gibi binalarda yangın güvenliği adına da farklı yöntemlerin geliştirilmesine ve uygulanmasına neden olmaktadır. Ülkemizde binalarda yangın güvenliği, yangın durumunda kaçış ve boşaltma olanaklarının oluşturulması, yangının etkilerine karşı binanın mukavemetinin korunması adına kullanılan yapı malzemelerinin yangına dayanımlarının yeterliliği, mevcut binanın fiziksel koşullarının yangının ve dumanın yayılmasını en aza indirgeme doğrultusunda proje çalışmalarının oluşturulması, yangın durumunda mal ve can kaybını önlemek ve itfaiye erlerinin etkin kurtarma operasyonu yapabilmeleri için itfaiye müdahale ve acil durum yönetim planlarının oluşturulması gibi bir dizi faktör Binaların Yangından Korunması Hakkında Yönetmelik teki hükme dayalı zorunluluklar ile sağlanır. Bu zorunluluklar, binaların tasarımında mimar ve mühendisler için rehber görevini üstlenmektedir. Ancak, yüksek binalar için sadece BYKHY in hükümlerine dayalı tasarımlar, yangın güvenliği adına fonksiyonel ihtiyaçların karşılanamadığı bazı durumları da doğurmaktadır. Bu nedenle ülkemizdeki inşaat firmaları yüksek katlı yapı projelerini tasarlarken BYKHY in yetersiz kaldığı noktalarda kabul edilebilir çıktılar ve kısıtlı olmayan sayıda çözümler üzerine odaklanma adına Avrupa EN ve Amerikan NFPA yangın yönetmeliklerinden de yararlanmaktadırlar. Beş bölümden oluşan bu çalışmanın birinci bölümünde, yangın ile alakalı genel bilgiler, yüksek sıcaklığın betonarme ve betonarmenin elemanlarına etkileri anlatılmıştır. İkinci bölümde, ülkemizde yangın yönetmeliğinin geçmişi, Avrupa EN ve Amerikan NFPA yangın yönetmeliklerinin uygulanış biçimi ile yanan malzemenin tasarım kriterleri anlatılmıştır. Üçüncü bölümde 5 bodrum kat, 1 zemin kat ve 44 normal kattan oluşan, İstanbul, Ümraniye, pafta 11, Ada 787, 32 numaralı parsel üzerinde yapılan rezidans binasının yangın güvenliğinin ilgili yönetmeliklere göre tasarımı üzerine incelemeler anlatılmıştır. Dördüncü bölümde rezidans binasının herhangi bir durumda yangın güvenliği adına aktif yangın önleme sistemlerinin çalışma senaryosu anlatılmıştır. Beşinci bölümde ise yapılan bu tez çalışmasının betonarme yüksek binalar açısından yangın güvenliği ile alakalı sonuçları ve öneriler anlatılmıştır.

People constructed structures for the requirement of shelter and protection, since the moment that there were human beings. Developed as a low-rise buildings up to the industrial revolution, began to develop vertically for different reasons such as social, cultural, economic and technical reasons in the end of nineteenth century Construction of high rise vertically is getting easy because of the scientific and technical developments of construction material and technology. High rise buildings are multi storey buildings that construct by using modern technologies and require specific solutions. Increasing population, rapid urbanization and housing, commercial requirements in developing and developed countries cause increasing demand for multi storey high buildings day by day. Especially in big cities like İstanbul, rapid urbanization and migration, cause that most of buildings are built as a new high rise buildings. High rise building construction has a lot of problems about structural analysis architectural and technical design and construction. So,fire safety has been gaining importance day by day with developing technology growing industry and a quality awareness in our countries as well in developed countries. Current fire protection strategy for a building often incorporates a combination of active and passive fire protection measures. Active measures, such as fire alarm and detection systems or sprinklers, require either human intervention or automatic activation and help control fire spread and its effect as needed at the time of the fire. Passive fire protection measures are built into the structural system by: • Choice of building materials • Dimensions of building components • Compartmentation, and • Fire protection materials These control fire spread and its effect by providing sufficient fire resistance to prevent loss of structural stability within a prescribed time period, which is based on the building‟s occupancy and fire safety objectives. In the development of new codes, many countries have adopted a multi-level approach to fire resistance design. At the highest levels, there is legislation specifying the overall goals, functional objectives, and required performance that must be achieved in all buildings. At a lower level, there is a selection of alternative means of achieving those goals. The three most common options are to: • Comply with a prescriptive “acceptable solution” • Comply using an “approved calculation method” • Carry out a performance-based “alternative design” from engineering principles using all the information available Standard calculation methods for all aspects of fire resistance design have not yet been developed for widespread use, so compliance with performance-based codes in most countries is usually achieved by simply meeting the requirements of “acceptable solutions” (a “deemed-to-satisfy” solution), or alternatively carrying out a performance based “alternative design” based on fire engineering principles. Alternative designs can often be used to justify variations from the “acceptable solution” in order to provide cost savings or other benefits. Codes differ around the world. They all have the objectives of protecting life and property from the effects of fire, but the emphasis between life safety and property protection varies considerably. For more than 25 years, European countries have been working on a new coordinated set of structural design standards known as the Structural Eurocodes. These are comprehensive documents that bring together diverse European views on all aspects of structural design for all main structural materials. The Eurocodes are being prepared by the European Committee for Standardization (CEN) under an agreement with Commission of the European Community. The Eurocodes recognize the need for member countries to set national safety standards that may vary from country to country, so each country‟s national standard will comprise the full text of the Eurocode with local modifications in a supporting document. In our country, technical regulations for buildings fire safety on the BYKHY 2009 which is now implemented many approaches are recommended for assessing the potentiality of egress in case of fire, the protection of strength of buildings against the effects of fire, adequacy of used materials in terms of fire resistance of building, design principles of existing buildings to minimize the spread of fire and smoke, prevention loss of life and property in case of fire, preparation of fire response and emergency management plans for effectively rescue operation by firefighters. These regulations are important for architects and engineers in the design of the building. The present master of thesis is composed of five chapters. First chapter is introduction of the thesis. The physical and mechanical properties of concrete and steel change when reinforced concrete members are exposed to high temperatures due to a given reason. As a result of these changes, concrete may exhibit damages, such as cracks and spalling accompanying significant bonding losses between steel and concrete. Therefore, the actual state of a construction should be correctly evaluated before deciding on damage evaluation a construction exposed to high temperatures, e.g. a fire. This evaluation requires a good level of knowledge about the behaviour of concrete and the changes in its physical, mechanical and thermo-physical properties under the effect of high temperature. A structure must be both sustainable and economical and it must fulfill some performance levels in both vertical service loads and horizontal earthquake loads, earth pressure loads etc. This obligation has critical importance for life safety. Behaviour of structure is very important for the performance level of structure under the effects of the earthquake and fire loads. In this chapter, investigations of the mechanical properties of reinforced concrete exposed to high temperatures are expressed. In this context is not intended to provide step-by-step design procedures. Rather, it provides general guidance on the approaches to, and practical aspects of, implementing a fire-resistant design approach for concrete buildings. In second chapter, Adequacy of prevalent regulations for high rise buildings is discussed. Some differences about design principles of high rise buildings are summarized. Importance of performance based design for high rise buildings is mentioned. Differences between design rules in BYKHY and Eurocode and NFPA, design principles of high rise buildings and the design rules of BYKHY are briefly mentioned. The information presented in this chapter is limited to passive fire protection measures only. The third chapter gives information about Suryapı Exen İstanbul high rise building construction. Building have five rigid basement, one ground floor and 44 typical floors. All stories have three meters of height. Building is assumed to be constructed in a high seismicity region considered regulation which is Turkish Seismic Design Code in which the building is expected to experience destructive ground shaking. Slab system of the structure is a two way, beam- supported system.Design of this slab system is made according to Turkish Regulations. In this context, the information relating to the location, fire safety designing, mechanical and electrical systems, architectural and technical arrangements of the project are described. Building service and fire protection equipments consist of heating, ventilating, and air-conditioning systems, smoke control, elevators, stokehole, fire detection, alarm, and communications systems and its cables, automatic sprinklers and other extinguishing equipment. In the fourth chapter, Fire scenario of Exen İstanbul high rise building construction is explained. Operation principles of the passive and active fire safety devices systems in case of fire are described. The fifth chapter is the final chapter and indicates the results of the study. The differences between design rules in BYKHY, Eurocode an NFPA, are explained. Behaviour of structure, adequacy of prevalent regulations for high rise buildings, architectural and structural design of the Exen İstanbul high rise project in terms of fire safety compliance under fire effects are briefly mentioned.