Türk yapım şantiyelerindeki israfların ve nedenlerinin tespit edilmesi ve yalın inşaat uygulamalarıyla çözüm önerisi geliştirilmesi
Identifying wastes and causes of wastes in Turkish construction sites and proposing solutions using lean construction methods
Yazar: ALPER TOKAT
Danışman: DOÇ. DR. ELÇİN FİLİZ TAŞ
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Mimarlık Ana Bilim Dalı / Proje ve Yapım Yönetimi Bilim Dalı
Derece: Yüksek Lisans, 2015
Konu: Mimarlık = Architecture

Özet:
Bu tez çalışmasında inşaat sektöründe oldukça yeni sayılabilecek bir endüstriyel verimlilik yöntemi olan Yalın İnşaat'ın, Türk yapım şantiyelerindeki israf türlerinin tespit edilmesinin ardından, uygulanması gerekliliğine yönelik alan araştırması sonuçları paylaşılmaktadır. Onbir sene öncesinde Türk yapım şantiyelerindeki israf türleri ve nedenlerinin incelendiği bir çalışma ile bu çalışmada yürütülen alan araştırmasının verilerinin kıyaslanması ve geçen zaman zarfında hangi etkenlerin değiştiği ve son duruma göre ne şekilde bir çözüm oluşturulması gerekliliği üzerine sonuçlar paylaşılmış ve öneriler geliştirilmiştir.
Günümüz dünyasında şirketler arası rekabet şartları oldukça zorlu bir hal almıştır. Şirketlerin kendilerini işlerinde sürekli, başarılı ve memnun müşteriler portföyüne sahip konumda tutmaları ancak sürekli gelişim ve iyileştirme faaliyetlerinin hayata geçirilmesi ile mümkündür. Bu iyileştirme faaliyetlerinden en çok fayda sağlayan ve kapsamlı olanlarından biri de Yalın Üretim ilke ve prensipleridir.
Bu doğrultuda önemli bir endüstriyel verimlilik sistemi olan Yalın Üretim, inşaat uygulamalarının kendine özgü yapısına göre uyarlanmış ve Yalın İnşaat çalışmaları ağırlık kazanmıştır. Çalışmada Yalın Üretim'in Yalın inşaat ile arasındaki ilişki açıklanmıştır. Yalın İnşaat uygulamalarının odaklandığı konular ve tekniklerine ek olarak; yurtdışında ve Türkiye'de bu konuya ilişkin literatür ve uygulama çalışmaları hakkında bilgiler verilmiştir.
Yalın İnşaat'ın odaklandığı konuların başında gelen israfın giderilmesi, tezin dördüncü bölümünde detaylıca ele alınmıştır. İsraf dünyada ve ülkemizde önüne geçilmesi için sistematik ve tutarlı çalışmaların yürütülmesi gereken önemli bir problem olarak karşımıza çıkmaktadır. Yapım şantiyelerindeki israfın da yüksek boyutlarda olduğu geçmişten günümüze karşılaşılan bir konudur. Bu sorunun giderilmesine ilişkin literatürde ve uygulamada pek çok çalışma olsa da bir yapım şantiyesi özelinde gerçekleşen israf türlerine ilişkin yeterli araştırma yapılmamıştır. Bu eksiklik nedeniyle planlanan ve hayata geçirilen arasında büyük maliyet, zaman ve kalite farkları doğmaktadır. Bu farkların ortadan kaldırılması veya minimize edilmesi için israf türlerinin ve süreçte fayda sağlamayan aktivitelerin doğru tespit edilmesi; ardından bunlara bilimsel yaklaşımlarla çözüm önerilerinin hayata geçirilmesi gerekmektedir. Yalın İnşaat ilke ve prensipleri bu noktada önemli etkiye sahip olduğu akademik çalışmalar ve uygulama örnekleriyle kanıtlanmıştır.
İsrafın giderilmesinin önemi göz önünde bulundurularak bu tez çalışmasında Türk yapım şantiyelerinde gerçekleşmekte olan israf türlerinin belirlenmesi, ağırlıklarının ve bunların nedenlerinin tespit edilmesi amacıyla bir alan araştırması yürütülmüştür. Araştırma Türkiye'deki yapım şantiyelerinde görev alan mimar ve mühendis yapım profesyonelleri hedef almış, elde edilen veriler kullanılarak Türk yapım şantiyelerindeki israf türlerinin ve nedenlerinin analizleri yapılmıştır. 
Bu analizler doğrultusunda, onbir sene önce Türk yapım şantiyelerindeki israf türlerinin ve israf nedenlerinin araştırıldığı çalışmanın bulguları ile bu güncel çalışmanın bulguları kıyaslanmıştır. Bulgular sonucunda Türk inşaat sektörü şirketlerine bünyelerindeki yapım şantiyelerindeki israfı ortadan kaldırabilmeleri için uygulayabilecekleri Yalın İnşaat uygulamalarından özellikle tasarım, proje ve iş programı konusunda geliştirmeler yapılması yönünde önerilerde bulunulmuş ve dünyada bu uygulamaları gerçekleştiren diğer ülkeler gibi ülkemizin de önemli kazanımlar sağlayabileceğine dikkat çekilmiştir.

Abstract:
In this thesis, it is aimed to identify the waste types and their causes in Turkish construction sites and to propose solutions to eliminate the waste by using Lean Construction methods. The thesis study commences with a deep investigation and acquaintance of Lean Manufacturing and Lean Construction notions. Subsequently, with the intend of having a good command of the Turkish construction sites' present conditions, the waste types and causes are revealed with an extensive survey. Afterwards, the collected data is analysed and interpreted to develop solutions that will reduce waste in Turkish construction sites by proposing the use of Lean Construction methods which are fairly new in construction industry.
Competitive conditions between companies in the world today is very challenging. For the companies that want to keep themselves as lasting, successful and customer-satisfying, it is only possible through continuous development and implementation. The continuity of the development is possible with what is denotated as industrial productivity methods. The efforts on increasement of the productivity first initiated by Frederick Taylor, improved by Henry Ford and acquired a different dimension with the development of Toyota Production System (TPS) by Japanese production engineers Taiichi Ohno and Shigeo Shingo. Toyota Production System basically formed the basis of Lean Manufacturing that is a compliment of methods where only the processes that avails and integrates ideally are inclusive. Today Lean Manufacturing is an overall rules and principles complex that is needed and used by the companies for increasing the productivity, decreasing the lost, enlarging the employment, and so on. According to this need, before stating the rules and principles of construction information, the technics and methods which are related with construction area are picked from Lean Manufacturing and explained to show relation of Lean Manufacturing and Lean Construction.
Lean Manufacturing is being adapted for the applications in construction industry as well for about 30 years now. It has firstly anounced as Lean Construction in 1992 by the International Group of Lean Construction (IGLC) from Australia. Since then, many other researches, organizations and contruction companies focussed on all around the world. The use of this overall rules and principles in construction industry has became quite popular around Australia, United States, United Kingdom and many other countries in a short time period. Today the Lean Construction Institute based in United States is the most popular and active organization that promotes Lean Construction principles and organizing events about Lean Construction every year, globally. In this direction, it is revealed and discussed the essentials and main principles of Lean Construction, which has been adapted from Lean Manufacturing, and the relation between the two notions is explained. Correspondingly, the review of national and international literature and practices is presented with the focus on the practices and techniques of Lean Construction. Through these researches, it is clearly seen that construction sites has a huge waste problem from the beginning as well as other industrial areas. 
Lean Construction rules and principles are focussing on three major areas in a construction process: Waste, lean organization and Lean Production Delivery System (LPDS). All three are the most popular of these areas of the waste elimination.
Among all the issues and methods of Lean Construction, waste is the one to require concrete efforts to solve and to give concrete results at the end. Waste has been a huge problem for all of the industries since the industrial efficiency methods have discovered. The industrial efficiency methods has firstly been discovered by Frederick Taylor in the mid 1800s and has developed by Henry Ford in early 1900s. Waste and efficiency are as much big problem for construction sector also. This feature causes the waste to become the most focused issue of Lean Construction rules and principles. It is a major problem to be solved and prevented by using sistematic and consistent methods. The fourth chapter of this thesis discusses in detail the waste in construction sites and the Lean Construction methods developed for reducing it. 
Even if there are many literature research and practices for reducing or eliminating waste in construction sites, there are still huge differences in cost, time and quality between the planned and the implemented applications. To minimize or eliminate these differences, wastes and non-value added activities must be clarified and solved by scientific methods to put into practice. As it is revealed in academic papers and practices in various construction sites, Lean Construction techniques are proven to be quite useful to achieve the improvements in question. This is why it was considered necessary to suggest a model using Lean Construction techniques to reduce waste in Turkish construction sites.
Referring to the importance of eliminating the construction waste, in this thesis study, a survey was conducted with the aim of determining the waste types in Turkish construction sites. After collecting data with the survey, it is aimed to determine the weight of the waste types in order to specify their causes. In 2004, Polat & Ballard has determined the waste causes in Turkish construction sites and this study has led that the Turkish construction companies may still face the waste issue. Therefore, a construction site waste types and waste causes survey is prepared with the assumption that Turkish construction sites encounter the waste problem, and it contains 63 questions in total; 28 questions concerned about waste types, 35 questions related with the causes of these waste types. The target group of the survey includes architects, construction, mechanical engineers and electrical engineers, construction professionals who works in construction sites in the country. The survey was conducted with 36 construction professionals from 31 different company in 2014 and 2015.
In the light of the data obtained from the construction professionals, the analysis for the wastes and causes of the Turkish construction sites were made. It is confirmed that 64% of the participants agrees that these possible waste types are confronted in the construction sites. The prevelance of the waste types in Turkish construction sites are revealed from the collected data. It is seen that the highest prevelance of the waste types are in the following supergroups respectively: Malfunction of design, project and the master plan, Problem of manpower and Problem related with construction materials. The main waste types' group has been found that the Turkish construction companies have an excessive malfunction on collaborationg and communicating inbetween the professions. Beside the analysis of supergroups, the prevelance of each waste type are analysed independently as well and gave the result that the highest prevelance is in the mistakes of the application.
According to these analyses, findings of the research study on waste types and causes of wastes in Turkish construction sites, that conducted eleven years ago, and the findings of this study are compared. Also, the research study on waste types and causes of wastes in Abu Dhabi construction sites were compared for to show the differences of the waste types according to geography and climate difference. The comparison shows that today in Turkey, the most frequently encountered wastes are caused by the malfunction of design, project and the master plan in contrast with the data of eleven years ago which shows the supply problems were the main cause of construction waste in Turkish construction sites. This cause affecting the material supply, manpower, time management and cost estimation altogether and causes significant loss for construction firms. 
In consequence of these findings, several ways presented to achieve the goals to eliminate waste for Turkish construction industry, by pointing Lean Construction methods mainly focusing on the development of the design, project and the master plan issues. The major goal is to achieve and implement the Lean Production Delivery System for all Turkish construction companies, which must be promoted by the government or the Turkish Chamber of Contractors. By the means of that, the construction process can be way more efficient and the professionals from all other branches can communicate and understand each other in a better way, which will led the whole process as one. In conclusion, it is pointed that Turkish construction companies may provide significant gains by the awareness of these methods, just as the other countries in the world which have adapted the principles of Lean Construction.