Tutkallı Ahşabın Mimari Mekan Strüktürüne Etkisi

Abstract

Dış ülkelerde yüz yıldır başarı ile uygulanmakta olan "Lamine Ahşap Teknolojisi", yurdumuzda pek fazla uygulama alanı bulmamıştır. Avrupa'da 100, Amerika'da 75 yıldır yaygın bir şekilde kullanılmaktadır. Bu da ahşap malzemeye duyulan saygının kanıtı olmaktadır. Tez konum olarak "Lamine Ahşap Teknolojisi'"ni incelememin nedeni, ahşabın değişken bir malzeme olması ve uygulamalarda bu teknolojinin çok iyi sonuç vermesidir. Türkiye'de bu teknoloji hakkındaki yetersizlik son derece üzücü bir durum arz etmektedir. Bu sistemle geniş açıklıklar geçilmiş ve çok stabil yapı elemanları üretilmiştir. Aslında tek suçlu olarak kendimizi görmemiz gerekir. Ahşap malzemeye olan ilgisizlik (daha ziyade bina yapı elemanları boyutunda), devletimizin orman yönetmeliği konusundaki yetersizliği diğer negatif faktörlerdendir. Bu teknolojinin zamanla yurdumuzda yaygın bir şekilde uygulanması gerektiğini düşündüğüm için, sistem hakkındaki eksikliğimizi bir ölçüde kapatmak amacıyla bu çalışmayı yapmış bulunmaktayım. Ve uzun çalışmalar sonucu bu tez ortaya çıkmıştır. Altı bölümden oluşan bu tezin birinci bölümünde konuya istinaden giriş bölümü bulunuyor. İkinci bölümde tutkallı ahşabın tarihçesi, Türkiye'de ve Dünya'daki durum incelenmiştir. Üçüncü bölüm tutkallar hakkında genel bilgiyi içermektedir. Tutkal türlerine konu itibarı ile pek fazla değinilmemiştir. Tutkallı Tabakalı Ahşap Sistemler incelenmiş, genel anlamda ahşap malzemeye bakış, yapı elemanları, üretim aşaması, sistemin yararları ve sakıncaları bu bölümde yer almıştır. Beşinci bölümde bu teknoloji ile kullanılmakta olan konstrüksüyon tipleri araştırılmıştır. Bu bölümde bu teknoloji ile yapılmış örnekler görülecektir. Altıncı ve son bölümde tez konusu hakkındaki sonuçlar çıkarılmış ve bunun doğrultusunda öneriler söylenmiştir.

Glued laminated wood technology, which has been succesfully applied for the last century in foreign countries, does not have many fields of application in our country. This technology has been applied in United States of America for a century and in Europe for seventy years. It was first used over one hundred years ago in Germany and the technology was introduced to North America in 1934. Wood is a highly variable and heterogeneous material. Glued laminated timber is usually designed to reduce the variability of wooden beams through lamination and a random arrangement of week zones. The averaging effect holds on the macroscopic rigidity of the beam, which can be simply treated using the classical theory of multilayered composits. On the other hand the analysis of damage processes and ultimate strength of glulam beams require an accurate calculation of the stress field in the beam, especially after the first failure has occurred (stress redistribution effects). Glulam (Glued Laminated Timber) is a structural timber product manufactured by gluing together individual pieces of dimensioned lumber under controlled conditions. Laminating is an effective way of using high strength lumber of limited dimension to manufacture large structural elements in many shapes and sizes. The lumber used for the manufacture of glulam is a special grade (lamstock) which is purchased directly from lumber mills. It is dried to a maximum moisture content of 15 percent and it is planed to a closer tolerance than that required for dimension lumber. Glulam is a structural product used for headers, beams, girders, columns, and for heavy trusses. Glulam can be manifactured to an almost limitless variety of straight and curved configurations. It offers the Architect artistic freedom without sacrificing structural requirements. This is an evidence of the respect to wood. The reason why I choose "Glued Laminated Wood Technology" as the subject of my thesis is that wooden material is a variable material and its technology has very good results in the application. I made this study in order to fill the gap in this field to a certain extent and because I take the view that this technology should be utilitized in our country. Principal steps in the manufacture and erection of Glulam elements are as follows: 1. Selection, grading of lumber 2. Drying of lumber at the plant ovens 3. End joining of laminations 4. Spreading of adhesives 5. Clamping-forming 6. Finishing (planing, final cuts, metal connectors, hotels, impregnation) 7. Quality Control 8. Transport by normal or long trucks, ship, train to the construction site 9. Erection by fixed or mobile cranes at the site 10. Final touch-up at the site Advantages of Glulam construction include the provision to manufacture larger structural elements from small sizes of timber, giving better utilization of available lumber resources, the ability to achieve architectural effects through the use of curved shapes; the ability to design structural elements varying in cross section between supports; to achieve a high quality of fire safety compared with the other construction options; the succesful structural behaviour against Earthquake load due to its lightweight the ability to breathe and to react positively against water, vapour and harmful gases, great performance to decrease the maintenance costs of building. The main advantages of the laminated timber are: XI 1. Fire- Resistance The laminating timber constructions, correctly designed and taking in mind an eventual exposure to the flames, behave surprisingly good during a fire, and count on excellent fire strength properties. To achieve this, security rules that have been developed in the main building codes must be respected. 2. Lightness Its moderated weight constitutes constructions with reduced inertia, which is a very important advantage in a seismic country. In the south of Chile, in 1960, the wooden constructions resisted worlds most intensive earthquake of an century, avoiding victims and material demages. 3. Flexibilty The laminated timber permits the design of elements with very diverse forms, since the thickness of the sheets gives the possibility of building curved elements, something that isn't possible with natural wood. Furthermore, the section of an element can change depending on the mechanical requests. 4. Great Spans The glued laminated timber makes it possible to fabricate structural elements with great dimensions and covering large spans without intermediate supports. There are lots of constructions have been built with spans surpasing than 40 meters. 5. Excellent Heat Insulation The conductivity or thermic transmission is much lower in wood than in other materials. Therefore it has excellent insulant properties, contrary to other ones: copper, 320 kg.cal/mh°c; aluminium, 155 kg.cal/mh°c; steel, 58 kg.cal/mh°c; concrete, 1,2 kg.cal/mh°c; bricks, 0,5 kg.cal/mh°c; wood, 0,1 kg.cal/mh°c. 6. Chemical Strength Since lumber is a material in chemical balance with the environment, it doesn't reach with oxidant or reducing agents. This qualifies it as a clean material, and therefore very appropiate to be used in situations that produce corrosion on metals, for xii example for chemical products warehouses, fruit packing, constructions near to the coast, etc. The lumber is resistant to most acids and other corrosive agents. 7. Beauty The noble and warm character of the wood is specially present in the laminated timber structures. Its slenderness and shape give warmth and pleassure to inside and outside spaces; structures as well as surfaces covered with it. It's a misfortune that there is a lack of know-how in our country concerning this technology. It has been possible to reach as long spans as nobody imagined and to produce stable construction components by utilizing this technology. We shouldn't blame only ourselves; Apathy on wooden material (especially regarding construction components) and insufficiency of our states' forest regulations are other negative factors. Uses of Glulam in the world construction market: 1. The supports hall 2. Swimming pools 3. Congrees and Conference halls 4. Theatre, concert and disco halls 5. Restaurants 6. Shopping centers 7. Schools 8. Industrial plants 9. Large warehouses 10. Closed waste- water purification centers 11. Houses, pergola and gazebo type outdoor structures. In the first chapter of my thesis, which consist of six chapters, there is a general information about the glued laminated wood technology. In the second chapter the history of glued laminated wood technology and the situation in the world and in Turkey have been discussed. Third chapter contains a general information about glues. Types of glues have not been discussed in details. xiii In the fourth chapter glued laminated systems, production phase, construction components, advantages and disadvantages of the system have been discussed. You can also find a general view to the wooden materials in this chapter. Construction types which utilizes this technology have been presented in the fifth chapter. It's possible to find samples from worldwide applications. In the last chapter, It is given that the results and advices about this technology in our country.