Yapım sürecinde fiziksel olmayan israfların yönetimine yönelik süreç analiz modeli
Yapım sürecinde fiziksel olmayan israfların yönetimine yönelik süreç analiz modeli
Dosyalar
Tarih
2020
Yazarlar
Can, Gizem
Süreli Yayın başlığı
Süreli Yayın ISSN
Cilt Başlığı
Yayınevi
Lisansüstü Eğitim Enstitüsü
Graduate School
Graduate School
Özet
Ülkelerin ekonomik durumları ile doğrudan etkileşim içerisindeki sektörlerden biri olan inşaat sektörü, birçok alt sektöre öncülük etmektedir. Ülke ekonomilerinin büyümesine bağlı olarak, daha fazla büyüme kaydedebilen sektör; benzer şekilde ekonomilerin daralması ile de olumsuz yönde etkilenmekte ve kendisine bağlı diğer sektörleri de etkilemektedir. Ülke ekonomisi ve diğer sektörler ile entegre biçimde yol alan inşaat sektöründe, bu dalgalanmaları daha kontrollü bir şekilde yönetmek önemli ve gereklidir. Küçülme dönemleri, kriz dönemleri olarak da düşünüldüğünde; sektörün bu gibi durumlar karşısında, mevcut durumunu en iyi şekilde koruyabilecek, büyüme dönemlerinde ise ivmesini artırabilecek uygun strateji ve yönetim biçimlerine ihtiyacı bulunmaktadır. Doğru ve uygulanabilir stratejiler ve yönetim metotları neticesinde, kriz dönemleri fırsata çevrilebilmekte ve faydalı sonuçlar elde edilebilmektedir. Bu durumun en somut örneği, otomotiv sektöründe faaliyet gösteren Toyota'dır. Firma, 1980'li yıllara gelene kadar tarihinde önemli krizlere tanıklık etmiş, uyguladığı strateji ve yöntemler sayesinde de kriz dönemlerini fırsata çevirebilmiştir. Hatta Toyota, büyüme süreçlerinin en parlak dönemlerinde bile, "kriz yoksa, kriz yaratın" ve "sorun yoksa, sorun vardır" yaklaşımlarını benimsemekte, geliştirdiği strateji ve yöntemlerini uygulamaya devam etmektedir. Bu strateji ve yöntemlerin temelinde ise, israflardan arınarak değeri artırmayı esas alan "yalın düşünce" bulunmaktadır. Yalın düşüncenin, üretim sektörüne kazandırdığı faydalar sonucunda, bu düşüncenin inşaat sektörüne de uygulanabileceği fikri ile; israfları uzaklaştırarak, proje hedeflerinin gerçekleştirilmesi ve bina üretim süreçlerinin etkili şekilde yönetilmesi gündeme gelmiş, "yalın inşaat" kavramı ortaya çıkmış ve inşaat sektöründe yalınlaşma çabaları başlamıştır. İnşaat sektöründe yalınlaşabilmenin en önemli adımlarından birisinin, "israf" kavramını doğru anlayarak, israf yönetiminin yapılması gerektiği düşünülmektedir. Bina üretim sürecinde israf; sadece malzeme, ekipman israfları şeklinde fiziksel olarak ortaya çıkmadığı gibi, fiziksel olmayan israflar olarak da meydana gelebilmektedir. İşte bu noktada; süre, maliyet ve kalite israfları olarak ifade edilen fiziksel olmayan israfların, özellikle bina üretim sürecinin, üretim adı altında geniş yer kaplayan yapım süreci kapsamında, anlaşılması ve yönetilebilmesi önemlidir. Böylece, israfların sektörün hassas noktalarından birisi olduğunu bilerek ve inşaat sektörü açısından sistematik bir şekilde değerlendirerek; israf sorununun çözümü için uygun çözüm yöntemleri aramanın ve bu yöntemleri sektörde uygulanabilir hale getirmenin son derece önemli, kazançlı ve motive edici olacağı düşünülmektedir. Yapılan doktora tez çalışması ile birlikte; yalın düşünce ve yapılan araştırmalar çerçevesinde bina üretim süreci için "israf" kavramı yeniden ele alınmış ve yalın düşünceye göre, bina üretim süreci israflarına ait sınıflandırma sistemi oluşturulmuştur. Fiziksel olmayan israflar, yapım süreci kapsamında değerlendirilmiş ve inşaat sektöründe faaliyet gösteren ana yüklenici firmaların, yapım sürecindeki fiziksel olmayan israflarını yönetebilmeleri için, süreç analiz modeli oluşturulması amaçlanmıştır. Ayrıca; ülkemizde henüz böyle bir modelin bulunmaması ve yurt dışındaki mevcut çalışmaların da çoğunlukla fiziksel israflar kapsamında üretilmesi sebebiyle; ortaya konulan tez çalışması ile birlikte, fiziksel olmayan israflar ve bu israflara yol açan israf nedenlerinin belirlenmesi ve analiz edilmesi de hedeflenmiştir. Söz konusu amaca ulaşabilmek için gerçekleştirilen doktora tezi toplamda altı bölümden oluşmaktadır. Tezin ilk bölümünde; problemin tanımlanması yapılarak, tezin amaç ve kapsamı ile yöntemine yer verilmektedir. Tezin ikinci bölümünde; yalın düşünce, yalın inşaat, israf kavramı ile israf nedenlerine yönelik literatür araştırması yapılmaktadır. Tezin üçüncü bölümü ise, alan araştırmasının yapıldığı bölümdür. Bu bölümde, inşaat sektöründeki fiziksel olmayan israflara yol açan ve yapım sürecini etkileyen tasarım süreci israf nedenleri ile yapım süreci israf nedenlerinin tespit edilmesi ve israfların yönetimine ihtiyaç olup olmadığına dair sektördeki mevcut görüşün tespit edilmesi amacıyla anket çalışması gerçekleştirilmektedir. Anket çalışmasının ardından, anket bulguları açıklanarak değerlendirmeler yapılmaktadır. Tez çalışmasının dördüncü bölümünde sırasıyla; Delphi tekniği, israf kütüğü ve kök-neden analizi olmak üzere üç farklı yöntem kullanılarak, israf nedenleri analiz edilmektedir. Her analiz sonucunda, ilgili analize ait bulguların istatistiksel analizleri ve gerekli değerlendirmeleri yapılarak, bir sonraki analize geçilmektedir. Analizler neticesinde belirlenen kritik israf nedenlerine ait kök nedenlerin ortaya konması ile, dördüncü bölüm tamamlanmaktadır. Beşinci bölümde ise, yapım sürecinde fiziksel olmayan israfların yönetimine yönelik süreç analiz modeli oluşturulmaktadır. Tezin son bölümünde ise, yapılan çalışmalar özetlenerek, tez kapsamında ortaya konan model ve çalışmalara ait anahtar bulgulara, değerlendirmelere ve önerilere yer verilmektedir.
Construction industry that directly interact with the national economics pioneers to many sub-sectors. The construction industry could achieve growth more based on the national economy. Similarly, the industry could be adversely effected by the economic constriction and effect also its sub-sectors directly. It is important and essential to manage those fluctuations in a controlled manner in the construction industry that has a close relation with the national economy and other sectors. When the periods of regression are thought as crisis periods; the construction industry needs the convenient strategies and polities to could hold the line in such circumstances and accelerate during the boomers. In consequence of appropriate, practicable strategies and management methods, the crisis periods could be turned into an opportunity and it could be gained advantage. The best sample of this situation is Toyota that acts at automotive industry. The establishment has testified to important economic crises well into the 1980s and they have turned the those crisis to opportunity with the strategies and methods that they have applied. Further, Toyota has embarked on the approaches that "no crises, create crises" and "no problem, big problem" during the their shining era. And they still keep on adopting their those strategies and methods that they had developed. There is "lean thinking" which bases on increasing value while removing wastes, at the basis of those strategies and methods. As a result of the benefits that the lean thinking brings in to production industry, it has come up that adapting this idea to the construction industry. In this way, it has been thought achieving the project targets and managing the building production process in an effective manner as soon as minimizing or removing wastes. After all, "lean construction" term has been come up and lean ventures has started at the construction industry. It is thought that one of the most important step for lean implementation at the construction sector is understanding what is the real meaning of "waste" term and managing the construction wastes. Not only waste is occured as physically such material, equipment wastes but also it is occured as non-physically like time, cost and quality wastes. At this point, it is important to manage those non-physical wastes, within the scope of construction process which has been evaluated under the name of production and has a large and important place in building production process. Thereby, it is thought that it will be profitable, motivator and important to improve and apply new solution methods against to waste problem considering wising up that the wastes are most important points of the construction industry and should being evaluated the wastes systematically. At this doctoral thesis; "waste" term has been handled within the scope of lean thinking. In scope of recent researches; "waste" has been defined and construction waste classification system have been introduced for building production process considering lean thinking. And then, non-physical wastes have been evaluated within construction process. Thus, with this thesis; it has been aimed to generate a process analysis model for a main contractor to manage the non-physical wastes during the construction process. Because of the fact that, there is not such a kind of model at our country and many studies at the abroad are generally based on physical wastes; with this doctoral thesis, it has been targeted to present and analyse the non-physical wastes and theis causes. This doctoral thesis consists of six main chapters. The first chapter of the doctoral thesis is the introduction one. The introduction consists of background to the study, the problem statement, the purpose of the thesis, the scope of the thesis, and methodolgy overview. In the second chapter of the doctoral thesis, relevant literature review is given. In the literature review, firstly the concept of lean thinking, lean production and lean construction are explained with the management issues. Then, waste and waste management are presented considering the relation with value issue. Also, waste and waste management at construction industry are examined in detail. Subsequently, wastes that are occured during building production process with their causes at design and construction processes are given. The third chapter of the doctoral thesis includes field study about causes of the non-physical wastes. In this chapter, questionnaire study is used for determining causes of wastes. After explaining the aim, scope and methodology of the questionnaire, findings about the questionnaire deal with such as participants, general analysis about wastes of building production process, causes of wastes at the building production process and managing the causes are explained and evaluated. Then, the causes of design process wastes that have the highest index value and effect the construction process and the causes of construction process wastes, which have the highest index value are determined to analyse the causes of wastes. Those determined causes of wastes are total twenty-six that seven of them belongs to design process effecting construction process and nineteen of them belongs construction process. The fourth chapter of the thesis is the chapter of analysis. In the fourth chapter, twenty-six causes of wastes which are determined at the third chapter are analysed. For analysing the causes of wastes that have the highest index value, three different analysing methods are used in this chapter. These are respectively Delphi technique, waste register and root cause analysis. At Delphi technique, expert team that consisting on ten experts is specified after Delphi set of question is prepared according to third chapter's outputs. Then, two rounds of Delphi set of question is sent to the expert team and all the answers of experts are determined the questions that they have consensus on. At the end of first and second Delphi rounds, the causes of wastes that are consensused on by the expert team are identified according to probability of realization and waste cause effects. Those causes of wastes which are analysed by Delphi technique are totaly fifteen. While five of those causes belongs to design process effecting construction process, ten of them belongs directly construction process. Total fifteen causes of wastes are analysed generating waste register stated as the second step of analysis method at the fourth chapter. Total index value of fifteen causes of wastes' are calculated according to probability of realization and non-physical waste (time, cost, quality) effect index values that are obtained by experts' answers which are given at Delphi technique. And then, all fifteen causes of wastes are prioritized according to total index values of each cause of waste on the waste register. After prioritisation, the most five critical causes of waste are determined considering highest total index values. The third step of analysis method at the fourth chapter is root-cause analysis. In this step, the most five critical causes of wastes' root causes are investigated. For this, focus group discussion is realized. According to the given answers by common consent of the focus group, main causes are determined and those main root causes also evaluated for overcoming them. The fifth chapter of the thesis is the chapter that is the process analysis model is presented. Features of the model that is named "Process Analysis Model Towards Management of Non-Physical Wastes in the Construction Process" is determined in a detail way and correlated with the thesis structure. Then, for making easier the implementation of the model, a checklist that is named " Checklist For Process Analysis Model Towards Management of Non-Physical Wastes in the Construction Process" is generated. The last chapter of the doctoral thesis is the conclusion part. The conclusion consists of the summary of the all studies conducted through the doctoral thesis. Also, in this chapter, key findings are explained with suggestions.
Construction industry that directly interact with the national economics pioneers to many sub-sectors. The construction industry could achieve growth more based on the national economy. Similarly, the industry could be adversely effected by the economic constriction and effect also its sub-sectors directly. It is important and essential to manage those fluctuations in a controlled manner in the construction industry that has a close relation with the national economy and other sectors. When the periods of regression are thought as crisis periods; the construction industry needs the convenient strategies and polities to could hold the line in such circumstances and accelerate during the boomers. In consequence of appropriate, practicable strategies and management methods, the crisis periods could be turned into an opportunity and it could be gained advantage. The best sample of this situation is Toyota that acts at automotive industry. The establishment has testified to important economic crises well into the 1980s and they have turned the those crisis to opportunity with the strategies and methods that they have applied. Further, Toyota has embarked on the approaches that "no crises, create crises" and "no problem, big problem" during the their shining era. And they still keep on adopting their those strategies and methods that they had developed. There is "lean thinking" which bases on increasing value while removing wastes, at the basis of those strategies and methods. As a result of the benefits that the lean thinking brings in to production industry, it has come up that adapting this idea to the construction industry. In this way, it has been thought achieving the project targets and managing the building production process in an effective manner as soon as minimizing or removing wastes. After all, "lean construction" term has been come up and lean ventures has started at the construction industry. It is thought that one of the most important step for lean implementation at the construction sector is understanding what is the real meaning of "waste" term and managing the construction wastes. Not only waste is occured as physically such material, equipment wastes but also it is occured as non-physically like time, cost and quality wastes. At this point, it is important to manage those non-physical wastes, within the scope of construction process which has been evaluated under the name of production and has a large and important place in building production process. Thereby, it is thought that it will be profitable, motivator and important to improve and apply new solution methods against to waste problem considering wising up that the wastes are most important points of the construction industry and should being evaluated the wastes systematically. At this doctoral thesis; "waste" term has been handled within the scope of lean thinking. In scope of recent researches; "waste" has been defined and construction waste classification system have been introduced for building production process considering lean thinking. And then, non-physical wastes have been evaluated within construction process. Thus, with this thesis; it has been aimed to generate a process analysis model for a main contractor to manage the non-physical wastes during the construction process. Because of the fact that, there is not such a kind of model at our country and many studies at the abroad are generally based on physical wastes; with this doctoral thesis, it has been targeted to present and analyse the non-physical wastes and theis causes. This doctoral thesis consists of six main chapters. The first chapter of the doctoral thesis is the introduction one. The introduction consists of background to the study, the problem statement, the purpose of the thesis, the scope of the thesis, and methodolgy overview. In the second chapter of the doctoral thesis, relevant literature review is given. In the literature review, firstly the concept of lean thinking, lean production and lean construction are explained with the management issues. Then, waste and waste management are presented considering the relation with value issue. Also, waste and waste management at construction industry are examined in detail. Subsequently, wastes that are occured during building production process with their causes at design and construction processes are given. The third chapter of the doctoral thesis includes field study about causes of the non-physical wastes. In this chapter, questionnaire study is used for determining causes of wastes. After explaining the aim, scope and methodology of the questionnaire, findings about the questionnaire deal with such as participants, general analysis about wastes of building production process, causes of wastes at the building production process and managing the causes are explained and evaluated. Then, the causes of design process wastes that have the highest index value and effect the construction process and the causes of construction process wastes, which have the highest index value are determined to analyse the causes of wastes. Those determined causes of wastes are total twenty-six that seven of them belongs to design process effecting construction process and nineteen of them belongs construction process. The fourth chapter of the thesis is the chapter of analysis. In the fourth chapter, twenty-six causes of wastes which are determined at the third chapter are analysed. For analysing the causes of wastes that have the highest index value, three different analysing methods are used in this chapter. These are respectively Delphi technique, waste register and root cause analysis. At Delphi technique, expert team that consisting on ten experts is specified after Delphi set of question is prepared according to third chapter's outputs. Then, two rounds of Delphi set of question is sent to the expert team and all the answers of experts are determined the questions that they have consensus on. At the end of first and second Delphi rounds, the causes of wastes that are consensused on by the expert team are identified according to probability of realization and waste cause effects. Those causes of wastes which are analysed by Delphi technique are totaly fifteen. While five of those causes belongs to design process effecting construction process, ten of them belongs directly construction process. Total fifteen causes of wastes are analysed generating waste register stated as the second step of analysis method at the fourth chapter. Total index value of fifteen causes of wastes' are calculated according to probability of realization and non-physical waste (time, cost, quality) effect index values that are obtained by experts' answers which are given at Delphi technique. And then, all fifteen causes of wastes are prioritized according to total index values of each cause of waste on the waste register. After prioritisation, the most five critical causes of waste are determined considering highest total index values. The third step of analysis method at the fourth chapter is root-cause analysis. In this step, the most five critical causes of wastes' root causes are investigated. For this, focus group discussion is realized. According to the given answers by common consent of the focus group, main causes are determined and those main root causes also evaluated for overcoming them. The fifth chapter of the thesis is the chapter that is the process analysis model is presented. Features of the model that is named "Process Analysis Model Towards Management of Non-Physical Wastes in the Construction Process" is determined in a detail way and correlated with the thesis structure. Then, for making easier the implementation of the model, a checklist that is named " Checklist For Process Analysis Model Towards Management of Non-Physical Wastes in the Construction Process" is generated. The last chapter of the doctoral thesis is the conclusion part. The conclusion consists of the summary of the all studies conducted through the doctoral thesis. Also, in this chapter, key findings are explained with suggestions.
Açıklama
Tez (Doktora) -- İstanbul Teknik Üniversitesi, Lisansüstü Eğitim Enstitüsü, 2020
Thesis (PhD) -- İstanbul Technical University, Graduate School, 2020
Thesis (PhD) -- İstanbul Technical University, Graduate School, 2020
Anahtar kelimeler
Yapım süreci, Süreç analizi, Fiziksel olmayan israfların yönetimi,
Construction process, Process analysis, management of non-physical wastes