Performans yaklaşımı ile yapı bileşenlerinin değerlendirilmesi için bir yöntem üzerine inceleme
Research on a system for evaluating materials that make up the fabric of buildings with the performance approach
Yazar: AYŞE YONCA SİRMEN
Danışman: PROF. DR. ERTAN ÖZKAN
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Yapı Bilgisi Ana Bilim Dalı
Derece: Yüksek Lisans, 1997
Konu: Mimarlık = Architecture
Dizin: Performans değerlendirme = Performance evaluation ; Yapı malzemeleri = Building materials ; Yapı sistemleri = Structure systems

Özet:
Malzeme, yapı sistemi ve bileşenlerinde ortaya çıkan performanslarındaki başarısızlık, son yıllarda görülen problemlerin başındadır. Bu çalışma, başarısızlıklardan elde edinilen deneyimlere dayandırılarak, performans yaklaşımı ile yapı bileşenlerinin değerlendirilmesi için bir yöntem üzerine incelemeyi içermektedir. İlk iki bölümde, sorunların oluştuğu çevre ve kapsamı tanımlanmaktadır. Mevcut eski yapıların yeniden kullanıma kazandırılması maksadı ile, malzemelerin ve bileşenlerinin değerlendirilmesinde performans yaklaşımı anlatılmaktadır. Üçüncü bölümde performans değerlendirilmesi için beş ilkeden oluşan bir yöntem önerilmektedir. İlkeler, değerlendirme öğeleri amaç, kaçınılması gerekenler ve kontrol altoda 'çoktan aza geçiş', 'denge', 'ayrı davranış ve özellikler', 'süreklilik' ve 'kötümser yaklaşım' başlıkları ile sıralanmaktadır. Uygulama esasları anlatılmıştır. Dördüncü bölümde çevre koşullarındaki değişmeler ve bunların malzeme ve yapı sistemi üzerindeki etkilerine değinilmektedir. Beşinci bölümde önerilen ilkelerin tam olarak uygulanabilmesi için başlıca yapı malzemelerinin özelliklerine değinilmiştir. Yapı malzeme ve bileşenlerinin davranışlarında bozulmalar ile malzemeleri etkileyen kuvvet, ısı, su ve nem ilgili etmenler açıklanmıştır. Yapı malzemeleri ve bileşenlerinin performansında mutlaka bir başarısızlık oranı vardır. Bu başarısızlık oranını azaltmak, ancak sistemin iyi değerlendirilmesi ile mümkün olabilir. Önerilen yöntemde, beş temel ilke ile malzeme ve bileşenleri performans açısından değerlendirilmesi ortaya koyulmuştur. Beş ilkenin tam olarak uygulanabilmesi için yapı malzeme ve bileşenlerinin davranışları bilinmesi gereklidir. Bu yaklaşım mevcut yapıların bileşen düzeyinde doğru bir biçimde değerlendirilerek iyileştirilmesi, tasarım evresinde ise gerçekleştirilmesi tasarlanan yapının kullanma evresinde göstereceği performansın önceden değerlendirilmesinde kullanılabilecek sistematik bir yöntem olarak görülmektedir. vii

Abstract:
Failures of materials, constructions and other parts of buildings, dissatisfaction with the environment and other criticisms about modern building have been frequently seen in the recent years. This study draws on and applies the lessons of the failures so that the performance of materials in building construction may be better achieved in the future. To evaluate the way materials perform that make up the fabric of buildings, there is a need to have an easy guiding principles. For this reason five principles are introduced. Apart from their use as an analytical tool in design, they should also serve as a useful checklist at meetings or on site. It should be noted that an understanding of the fundamentals of building is required if the full potential of the application of the principles is to be achieved. The application of the principles should highlight areas of possible weakness in a design. When analyzing a building some elementary aspects are overlooked. There are five principles which assists in exposing weaknesses or potential weaknesses in the detailed design of a construction: 'Hİgh>Low', 'Separate Lives', 'Continuity', "Balance1, and 'Creative Pessimism'. They can be grouped under the title objectives, constraints and control. The relations between the principles and examples are shown below. It can be seen that where constraints and objectives have two principles, control has only has one principle which is related to all of the principles. vniPRINCIPLES FOR BUILDINGS 1. HIGH > LOW * Gravity (water flow/structure) (damp>dry) * Temperature gradient (hot>cold) * Vapor pressure gradient (moist>dry) * Air pressure gradient (high>low) * Reversion (steel > iron) (processed>original) * etc. 2. SEPARATE LIVES * Differential movements * Differential durability * Incompatible materials * The process of assembly *etc. 3. CREATIVE PESSIMISM Allowances for uncertainty because the properties of all materials, their assembly and performance and the way a building is used are neither totally ideal nor totally predictable * Structure * Thermal Insulation * Fire protection * Cavity separator * Damp-waterproofing *etc. * With surroundings * Laminates * Between parts and the whole *etc. 4. CONTINUITY 5. BALANCE CONSTRAINTS CONTROL OBJECTIVES CONNECTIONS AND RELATIONS BETWEEN THE PRINCIPLES CONMH\IMS HIGH l()\\ OBIK ll\tS IÎM \N(J CONTROL.. creative'pessimism SEPARATE LIVES ^ ?*?"-. CONTINUITY IX. PRINCIPES: 1. HIGH > LOW : By its name, this principle implies that there is a gradient between the relative high and low values. The rising of performance standards may be described as increasing the steepness of the gradient between inside and external environments. Greater values will tend to flow to the lower values until it achieves some kind of a balance. 2. SEPARATE LIVES : As a result of their response to changing conditions, materials tend to be in a state of movement to be expected in particular cases will be determining factor. Some materials will react with others if the two different materials are in contact and there is another agency present, such as moisture. Therefore there may be either physical or chemical reasons for separating some materials from others (in other words, allowing the respective materials to have separate lives). 3. CREATIVE PESSIMISM : The principle of creative pessimism follows naturally from the inevitability of variations and uncertainty generally. Importantly, caution is signaled. It is in this sense that it is used in the principles. Furthermore, the principle underlines the need for all concerned with building to recognize and allow for the inherent and almost inevitable shortcomings at a given time in knowledge of materials, of the performance of elements and how buildings are designed, built and used. Creative pessimism, as here interpreted, helps to focus on reality. That is why it sits between objectives and constraints. 4. CONTINUITY: The term and the principle it describes should be self-explanatory. The thinking behind it is that no material can be expected to perform its intended function fully if it is not continuous. Structural continuity is probably the most obvious example of the absolute necessity for continuity. The same applies to other functional requirements such as damp and waterproofing, thermal insulation, sound insulation, fire protection and cavity separation. However, in some cases, " continuity of performance is achieved by a discontinuity of materials.5. BALANCE: A characteristic of constructions is that they create a different environment internally to that outside. A characteristic of environments is that they are changing virtually all the time. The objective is balance is to hold or maintain the natural balance of a construction relative to the environment within and outside a building. When either or both environments change, the related construction becomes or tends to become unbalanced to some extent. In trying to achieve what is in effect a new state of equilibrium with its environment, movements and/or adjustments of materials within a construction take place These may be facilitated or their worst effects reduced in a number of different ways, such as provision for movements, accommodating movements or changes and providing additional heating or cooling. The objective of balance also needs to be considered in another way. Certain composite materials or elements require arrangements to ensure that their inherent balance is maintained so as to avoid or reduce their distortion or deformation.. RULES AND PRECAUTIONS: Rules and precautions result from the practical experience gained from empirical or science-based approaches to the resolution of particular problems in design and/or construction. The resolution may or may not have involved the application of the principles directly or indirectly. Rules and precautions, unlike the principles, are constantly changing, sometimes rapidly. In some cases, further research into a particular subject or other aspects of it has led, understandably, to a change in advice that might have been given earlier. In view of the rapid way in which requirements in buildings have changed, it is not surprising that advice and recommendations, whether from research organizations or building regulations are being reviewed continually.. APPLICATION IN THEORY: Consider the flow diagram below. It starts at the top with the principles and finishes at the bottom with two categories of risk of failure, lowest and highest. An imaginary dividing line runs vertically between the two, On one side of this (i. e. the lowest risk of failure) is the path from the principles to the rules and precautions; on the other (i.e. the highest risk of failure), the need to compensate. xiIn the simplest and direct case, if all the principles for building can be adopted, the next step is to apply the relevant rules and precautions. If these can be adopted in their entirety then the end result will have the lowest risk of failure for that case. If not, then the end result will carry the highest risk of failure. On the other hand, if one or more of the principles for building cannot be applied then there is a need to consider compensation. The choice is whether to compensate or not. If the decision is not to compensate then the end result will have the highest risk of failure. If compensation chosen, the relevant rules and precautions need to be considered and, if adopted, the end result will have the lowest risk of failure. To summarize: in general, the lowest risk of failure (i.e. without quantifying its degree) results from one of two alternative actions: either adopting the principles and rules and precautions in their entirety or compensating for those principles that cannot be applied and adopting the relevant rules and precautions. The opposite occurs again from one or two alternative actions: either adopting the principles but not some or all of the rules and precautions or not compensating for those principles that are not adopted. PRINCIPLES YES RULES AND PRECAUTIONS NO COMPENSATE YES NO RISK OF FAILURE NO HIGHEST xu