Demiryolu projelerinde inşaata başlama bölgesinin belirlenmesi için çok kriterli karar verme yaklaşımı: Bir vaka analizi
Multi-criteria decision-making approach for selecting the starting location of construction in railway projects: A case study
Yazar: SERRA ACAR
Danışman: DOÇ. DR. ATİLLA DAMCI
İstanbul Teknik Üniversitesi / Lisansüstü Eğitim Enstitüsü / İnşaat Mühendisliği Ana Bilim Dalı / Yapı İşletmesi Bilim Dalı
Derece: Yüksek Lisans, 2022
Konu: İnşaat Mühendisliği = Civil Engineering
Dizin: DEMATEL = DEMATEL ; Demir yolu işletmeleri = Railway businesses ; Çok kriterli karar verme = Multi criteria decision making ; İnşaat projeleri = Construction projects

Özet:
İnşaat projelerinde proje yöneticilerinin rolü gelişen teknoloji, yeni dünya ve projelerin hedefleri doğrultusunda her geçen gün zorlaşmaktadır. Özellikle gelişen teknolojiye ve dünyaya ayak uydurmak farklı disiplinler ile entegre bir proje yönetim yaklaşımı sağlamaktadır. Her bir disiplinin tek bir proje altında yönetilmesi de ancak yapılan plana tüm tarafların uymasıyla sağlanır. Projelerin entegre yönetim anlayışıyla, süresinde, bütçesinde ve işverenin istediği kalitede tamamlanabilmesi de yetenekli proje yöneticileri ve doğru zamanda doğru karar almakla sağlanır. 
Planlama sürecini yöneten kişiler, elde ettiği bilgiler ve tecrübeler doğrultusunda ortaya çıkardıkları iş yapış modeli ile bir iş programı hazırlarlar. Planlama sürecinin tüm proje tarafından benimsenmesi ileride ortaya çıkması muhtemel risklerin, maliyet kayıplarının, organizasyon ve iletişimden kaynaklı hataların minimize edilmesi için önemlidir. İnşaat projelerinin yapısı gereğince karmaşık ve tekil olmasından dolayı zaman zaman ortaya beklenmeyen problemler çıkabilir. Bu öngörülmeyen problemler sonucunda da hazırlanan iş programı ile sahada yürütülen işler arasında uyumsuzluk olabilir. Bu gibi durumlarda hızlı karar alma, zaman kaybını ve dolayısıyla para kaybını önlemek demektir. Fakat karar verme süreçleri projelerin büyüklükleri, ekonomik şartlar ve teknolojik gelişmeler dolayısıyla git gide zorlaşmaktadır. Problemlere çözüm bulunurken karar verme modellerinden en uygununun seçilmesi gereklidir.
Bu tez çalışması kapsamında planlama süreçlerini destekleyici, çok kriterli karar verme yöntemlerinin kullanıldığı bir model önerilmiştir. Bu modelin proje kapsamında yapılan iş programını destekleyici veya proje yöneticilerinin kararlarına yol gösterici bir model olması amaçlanmıştır. Önerilen bu model kapsamında bir ulaştırma ve güzergah projesi olan demiryolu projesi üzerinde örnek proje incelemesi yapılmıştır. Bu nedenle demiryolu projesi karakteristik özellikleri göz önünde bulundurularak ve uzmanlar ile yapılan görüşmeler sonucunda modele uygun kriterler belirlenmiştir. Kriterlerin ağırlıkları DEMATEL yöntemi kullanılarak hesaplanmış ve karar hiyerarşisi oluşturulmuştur. Ardından ise 3 farklı çok kriterli karar verme yöntemi (TOPSİS, COPRAS ve EDAS) kullanılarak alternatiflerin öncelik sıralaması yapılmış ve sonuçlar birbiri ile karşılaştırılmıştır. 
Yapılan literatür araştırmasında ayrı ayrı hem planlama süreçlerinde kullanılan çok kriterli karar alma yöntemleri hem de ulaştırma projelerinde bu yöntemlerin hangi süreçlerde kullanıldığı incelenmiştir. Fakat yapılan çalışmalarda ulaştırma projeleri planlama süreçlerinde inşaata başlamak için bölgesel öncelik sıralaması yapılan bir çalışmaya rastlanmamıştır. Bu tez çalışmasının ileride yapılacak çalışmalara fikir vermesi hem de planlama süreçleri için girdi sağlaması amaçlanmıştır. 
Genel perspektiften çok kriterli karar verme yöntemleri ele alınmış ve önerilen model kapsamında kullanılan bu yöntemler açıklanmıştır. Ayrıca yöntemlerin detaylı çözüm adımları da tez kapsamında anlatılmıştır. Kullanılan tüm yöntemler genel olarak tanımlanmış ve uygulama süreçleri detaylı olarak açıklanmıştır. 
Son bölümde ise önerilen model içerisinde belirlenen ana ve alt kriterlerin hesaplanan ağırlıkları doğrultusunda, problem içerisindeki etkileri sunulmuştur. Önerilen model kapsamında belirlenen bazı kriterler proje tipine göre değişkenlik gösterebilir. Ayrıca ileride yapılacak çalışmalarda farklı kriterler modele eklenerek daha detaylı ve mevcut proje yönetimi araçlarını sadece destekleyici değil, alternatif oluşturabilecek bir karar verme modeli oluşturulabilir.

Abstract:
The role of construction project managers is getting harder day by day in line with the developing technology, the new world and the goals of the projects. Especially keeping updated with the developing technology and the world provides an integrated project management approach with different disciplines. The management of each discipline under a single project can only be achieved if all parties are agreed and follow the project plan. The completion of projects with an integrated management approach, on time, on budget and at the quality desired by the employer is ensured by talented project managers and taking the right decision in the right place and at the right time.
The project's work programme is prepared by the planning team in line with their knowledge and experiences. Following the work programme by the entire project stakeholders is important to minimize possible future risks, cost overruns, and organizational and communicational mistakes. Due to the complexity and singular nature of construction projects, unexpected problems may arise during all phases of the project. As a result of these unforeseen problems, there may be incompatibility between the project work programme and ongoing works carried out in the field. In such cases, quick decision-making may prevent loss of time and accordingly money. However, decision-making processes become increasingly difficult due to the size of the projects, economic conditions, and technological developments. While finding solutions to those problems, it is important to choose the most appropriate decision-making model.
During the construction many difficulties may be occur in the project. These difficulties may be encountered by the project team even before they start the project. Under these circumstances, the decisions are made by the decision makers to avoid time out and cost overruns.
In order to support planning processes in the construction projects, a multi-criteria decision-making method is proposed. Multi-criteria decision making is a field of research that analyses various options on a situation or research in daily life, personal decisions, social sciences, engineering fields, medicine, public and many other fields. In general, it offers solutions to support decision or planning problems involving more than one criterion. It creates a modelling based on the criteria and then helps analyse alternative solutions. The analysis phases first begin with the determination of the situation or problem to be decided. Then, evaluation criteria need to be established and alternatives to be evaluated must be identified. By following the method steps which change depending on the method to be used, the alternatives are evaluated according to the criteria and ultimately the alternatives are ranked according to their priorities
This model is intended to support the project work programme or guides the decision-makers of the project. A case study is conducted on a railway project, which is a transportation and alignment project. For this reason, considering the characteristics of the railway project and derived results from the interviews with the experts, the suitable criteria for the model were determined. The weights of the criteria were calculated using the DEMATEL method and the hierarchy tr ee was created. Then, by using 3 different multi-criteria decision-making methods (TOPSIS, COPRAS and EDAS), the alternatives were ranked in terms of their priority and the results were compared with each other.
In Section 2. , a detailed literature review is given regarding the thesis statement related topics. The multi-criteria decision-making methods and their area of usage were searched in the literature, particularly the ones related with planning processes of construction or any other projects. Most of the studies have been conducted by using not multi-criteria but Fuzzy logic. Besides that, the areas in which multi-criteria decision-making methods are used in transportation projects have been also searched in the literature studies. However, in the research conducted, there was no specific study regarding the region priority ranking in the planning processes of transportation projects. Therefore, this thesis would provide ideas for future studies and also inputs for planning processes. 
When a detailed review is conducted in the literature, it is observed that there is a lack of studies regarding the region priority ranking. Therefore, this thesis study also aims to fill the gap in the literature. 
A general information and definition of multi-criteria decision-making methods are given in Section 3. .  The methods used within the proposed model are explained with a detailed review consisting of all the solutions steps of the methods. 3 different multi-criteria decision-making methods (TOPSIS, COPRAS and EDAS) principles are stated in this section. 
TOPSIS is a method of compensatory aggregation that compares a set of alternatives by identifying weights for each criterion, normalising scores for each criterion and calculating the geometric distance between each alternative and the ideal alternative, which is the best score in each criterion.
COPRAS is used to assess the maximizing and minimizing index values, and the effect of maximizing and minimizing indexes of attributes on the results assessment is considered separately.
EDAS is a new and efficient multi criteria decision making method. The desirability of alternatives in this method is determined based on distances of them from an average solution. 
In the next Section 4. , a case study has been conducted for the proposed decision-making model. A railway construction project which has 300 km alignment in total, has been chosen. Alternatives were determined by dividing the 300 km total alignment into 10 equal sections and each of alternative has 30 km alignment in total. 4 main criteria and 16 sub criteria have been determined with experts by taking into consideration of their experiences and literature review regarding the railway projects' characteristic features. 
The experts were selected from among those who had railway project experience and worked in related projects between 5 and 15 years. Among the experts, three people were selected with a planning experience, one person is a senior manager, and the other person was selected from the profile of senior project manager. Particular attention has been paid to the fact that all experts are persons with experience in the work program in the past or present within the scope of technical office work. For this reason, evaluating the work from both the office and field perspective is valuable for problem solving.
Considering the literature review, the prior criteria is determined as materials and their manufacture area. After discussions with the experts, they also stated that that haul measure of the material and quarries are the most important issues to be considered due to operational problems. 
There are some other issues considered while determining the criteria. One of them is weather conditions which is a subject to prepare work schedule. This is an important issue to take into consideration to forecast the seasonal workdays due to time constraint of the project. 
The other issue is related with design. The quantities provide the amount of works identified by the drawings and specifications in the design. The quantities help to calculate efficiency and outline number of construction units in a project work programme. Therefore, earthquake has been taken into account due to its effect on the design measures.
The criteria within the proposed model are construction work amounts (culvert length, bridge length, cut volume and fill volume), source distance (longest distance from borrow pit and longest distance from quarry), required material amounts (ballast, sub ballast and aggregates), natural hazards (monthly average rainfall, medium flood risk length and earthquake) and construction costs (bridge cost, culvert cost, cut cost and fill cost). The case study reveals that 
Afterwards, the weights of all criteria were calculated. The values of all alternatives were applied in the proposed model and subsequently the alternatives are ranked in terms of their priority.   
The study reveals the effects of all criteria to the proposed model. Since the weightages of criteria have been calculated by using DEMATEL method, it is observed that which criteria is the cause and which criteria is the result in the proposed model.
The findings and suggestions are given in the last section. In the literature, when the characteristic features of railway projects are searched, it has been seen that most of the studies have been made regarding the material properties and application methods used in the railway projects. When the results of the calculated criteria weights are calculated, the weights of the ballast and sub-ballast material criteria are the highest weights. Thus, it has been seen that the criterion weights calculated by the studies on ballast and sub-ballast materials are compatible with the material. 
When a detailed review on the results is conducted, it is seen that the work amount has the highest weightage and then cost, required material amounts, natural hazards and source distance are following respectively in terms of main criteria. Besides ballast and sub-ballast material amounts are the highest weightage in terms sub criteria. 
Considering the project type and its scope, the criteria can be change or more criteria can be added for the future studies. Additional criteria may allow more detailed decision-making model which would not only help to support decision makers or project work programme but also would create an alternative project management tool.  
By evaluating the ranking of alternatives which shows from which location to start construction, both information and alternatives can be provided to the problem solutions related to the mobilization or production facility installation location. Therefore, this thesis methodology may help future studies regarding the selection of location of mobilization area or any facilities related with project.
As a result, on the other hand in future studies, by adding different criteria to the problem, a more detailed decision-making model can be created that will not only support but also create an alternative to existing project management tools. 
This thesis study is open to be improved and the model can be used more effectively.