Please use this identifier to cite or link to this item: http://hdl.handle.net/11527/16655
Title: Kamu inşaat projelerinin gerçekleştirilmesinde süre uzama nedenlerinin analizi
Authors: Orhon, İmre
Gören, Selma Gül
75057
Yapı Bilimleri
Construction Sciences
Keywords: Kamu binaları
İnşaat projeleri
Public buildings
Construction projects
Issue Date: 1998
Publisher: Fen Bilimleri Enstitüsü
Institute of Science and Technology
Abstract: İnşaat sektörü, gerek milli gelire katkı, gerek yeni iş alanları ve olanakları yaratma gerekse diğer endüstrilerle ilişkiler yönünden ekonominin en önemli iş kollarından biridir. Diğer sektörlerde faaliyet gösteren kuruluşlarla karşılaştırıldığında bu alandaki kuruluşların çok farklı özellikleri vardır. İnşaat projelerinin yapım süresinin uzun olması, iklim koşullarından etkilenebilmesi, üretimin sabit bir yerde yapılmasının mümkün olmamasına bağlı olarak sabit işgücü, malzeme, ekipman ihtiyacının standart olarak hiç bir zaman belirlenememesi, gerçekleştirilen her projenin birbirinden farklı olması, projeleri gerçekleştirecek yüklenici kuruluşların farklı olması gibi nedenlerle bu sektörde faaliyet gösteren kuruluşların, diğer iş kollarında bulunan kuruluşlara göre farklı sorunları vardır. Özellikle bu alanda faaliyet gösteren ihale yöntemiyle kamu projelerini gerçekleştiren yüklenici inşaat kuruluşları, yatırımcının sermayesi ile iş yapan kuruluşlardır. Yatırdıkları sermaye ile değilde gerçekleştirdikleri projeler ile varlıklarını devam ettirebilirler. Bu nedenle de inşaatın yapım sürecininde rasyonel şekilde kullanımı mecburiyeti doğar. Bu özellikleri nedeni ile diğer sektörlerdeki kuruluşlardan ve inşaat sektöründe kendi sermayesi ile iş yapan kuruluşlardan farklı olarak yapım sürecine ilişkin farklı sorunlara sahiptirler. Yüklenici inşaat kuruluşlarının bir projeyi gerçekleştirmelerinin uzun bir süreyi gerektirmesi nedeniyle, içinde bulunulan ekonomik, çevresel, yasal koşullardan ve yatırımcıdan kaynaklanabilecek olumsuz faktörlerin yanında, birde sektörün kendi bünyesinden gelen bir takım olumsuzlukların olabileceğinin bilinmesi süre açısından önemlidir. Böylelikle önceden süre planlaması yapılan bir işin, tüm bu olumsuzluklara rağmen gerekli önlemlerin alınabilmesi ve gerekli süreye planlamada yer ayrılması imkanı elde edilerek işin planlanan sürede bitmesinin, yüklenici ve yatırımcı açısından önemi çok büyüktür. Bu nedenle de yüklenici inşaat kuruluşları ve yatırımcı için asıl önemli olan şey, finansal kararların verilmesinde etkili olan inşaat projesinin süresine ilişkin kararlarda sıklıkla meydana gelen yanılmalardır. Türk inşaat sektöründe önemli bir paya sahip olan kamu inşaat projeleri incelenmiştir.
Building activities consist of consturcting immovable properties, changing natural topography of earth and in order to meet the needs occured in time, the renovations, repairs and the destruction of the buildings. As a developing country, there is a huge demand of the products of the construction industry in Turkey. However, due to the specific causes, such as, the long construction terms, the differences of every projects for specific demands for different places and the impossibility of the repetition of the same project, there are very specific problems of the construction sector. Under these conditions, the main important issue for the contractor and the investor is: the mistakes in the estimation of the total construction term and the total cost which effect the main financial decisions. Investments of the long term building constructions are very risky, because of the special conditions of the construction industry of the every project and the impossibility of the certain prediction and the variation of the factors which effect the construction utilizing term and the cost. Due to the long construction completing term and the uncertainly of the changes (when and how intense) of the conditions, the situation of the factors in future is generally unknown. Therefore, at the beginning phase of a new enterprise, the proposed application term is generally based on the estimation and the insufficience of the datas which the estimation is based on and the negligence of the negative factors cause the mistakes on the estimations of the project term planning very often. In order to provide the completion of the projects in planned time, the factors which cause term extensions and their effects should be determined and the necessary preventions should be offered. It will be very helpful to make broad and improvable studies on this subject. The economical activitiy of the contractor companies whose productions are different from the other economical sectors is depended on the projects they realize. Furthermore, in the construction environment, there are many negative 4. The size of the project.(m2) 5. The organization of the contractor. 6. The completion date of the work on the contract. 7. The first assesment cost of the project b-) The issues derived from the revised work programmes, term extension decisions, realized work programmes and the petitions about the project application problems. 1. The real work beginning date. 2. Realized total project application term, (day) 3. The real work ending date. 4. The factors which cause term extensions and the term given for each factor, (day ) 5. Project realizing style. These derived issues were analyzed and these datas were obtained. The project realizing term (day) was calculated such as: the planned construction term was subtracted from the real project completing term.. The term extension factors were derived for each project and time extensions (day %) for each factor were calculated.. Factor analyze tables were drawn from the data based on (b) clause » From the factor analyze tables, the effectiveness tables were drawn with using term extension percentage of the factors for peojects and the Contractor specifications and their frequencies in the projects. After comleting these studies explained above, a three-stage process was derived : 1. The description of the events that cause term extensions 2. The defination of realized term extensions for each event 3. The calculation of the term extensions as the subtracting the planned time from the realized time. Due the current limitations of the sample group, this study does not include Workplace Conditions which can be occured from the organization of the Contractor company. There are 17 main factors derived from 42 projects. The most important factor based on term extension percentage is basement production increase ( % 69 ). factors and these factors variate relative to the conditions, the true estimation of the completion time of each project, the domination over the conditions and obtaining necessary preventions are very important for the investor whose aim is gaining maximum profit. Due to these reasons and according to the aim explained above, the archive documents of 42 projects which were constructed under the conditions comply with the Construction Tenders Act of Public Organizations No: 2886, by the construction contractor companies were studied. These are the projects of the schools, houses, hospitals, hostels and official service buildings which were completed between the years 1980-1995 and selected random. The scope of this study is limited with the projects which were completed by the construction contractor companies, in accordance with the " Fixed Unit Price Model ". On studying the documents of the projects completed according to this model, the resasons of term extension demands, the realized term extensions (as day) the deviations on the planned term were explained for each project. The main aim of this study is to provide the correct data for the estimation of the project term which is a main issue of the contract, signed between the contractor and the investor. The term extension demand according to the rules based on healthier reasons, in order to prevent term extensions to make suggestions for the changes on the body of the current law and obtaining necessary preventions at the project realizing phase. According to the aim and the limitations explained above, these documents of the sample group were examined: 1. Planned work programme which is the base of the contract, revised work programmes, unrealized programmes 2. The contract, the term extensions decisions documents of the contractor, the petitions about project application problems, official correspondences. 3. Architectural and Statics projects. The issues derived from these documents can be explained as: a-) Issues derived from the contract, architectural projects and the first work programmes: 1. Beginning date of the work on the conctract. 2. The type of the contract. 3. The typology of the project. According to the frequence in the projects, the main factor is the supplementary works which cause % 30 increase on the assessment price. After examining documents of 42 projects, the factors which cause term extensions can be explained as : A - The factors occured from the organization of the Investor : 1. The management problems 2. The delay of the place delivering B - The delay of financing and cash flow occured from the Investor : 3. The inssufficience of the allowances 4. The delay of the allowances 5. The lack of allowances 6. The delay of the ration C - The factors occured from the legal procedures 7. The delay of the contract 8. The supplementary works which cause % 30 increase on assessment price D - The factors occured from the design and the application of the projects. 10. The amendments on the projects 1 1. The changes on the production and the repairs 12. New productions 13. The changes on the land and the regulations concerning construction 14. The uncompletingn of the project 15. Production increase of the basement 16. The alterations of the land. E - Uncontrollable factor 17. Weather conditions These 17 factors derived from this study have significant differences from the factors derived from previous studies. There are not problems found occured from workplace area and the contructor's organization. Additionally, some factors comprise another, due to the subject area. The main difference of this study comes out fom the sample group which were the public construction projects must have been completed to comply with the Construction Tenders Act of Public Organizations and managed according to the body of the current law and the conditionals. Due to this restriction, the contractors could request the term extensions only for the reasons determined with the contract. In this study, the numeric (day) datas derived only for these 17 factors, therefore, statistical analyzes and calculations were made for these factors. It was estimated that, these term extension factors and term extension percentages can be varied according to the projects and the project specifications, therefore, two different analyzes were made. The sample group of 42 projects were separated to 4 different groups such as the size of the project, the typology, project realization method and the contractor's spesifications, based on the general datas derived from the projects. First, these 17 factors then the term extension percentage were examined according to the project and the contractor's specifications. The Man Whitney and Kruskal Wallis tests were applied to the results. The final results expressed that the term extensions were at the minimum for the school projects, maximum for the official service buildings and there were no significant difference of term extension percentage of the other projects. This study consists of six chapters. At the first chapter, the aim of the study, the plan of the thesis and the results which were expected to reach explained. At the second chapter, the general information on the sample group of the study, which is the realization of the public projects via tender method is introduced and the phases of the project realization are described. At the third chapter, the importance and the aim of the time planning was stressed and time planning phases and the method chosen explained. The list of conditions which determine the time extensions of the public constructions projects are introduced and the causes of time planning difficulties and the results of time deviations are described. At the fourth chapter, the factors which determine costruction completing time were explained, the factors were classified and examined. In order to know these factors and to obtain necessary preventions, these were compared with the ones derived from this study and the diffrences, the causes, importances and their effectiveness levels were examined. At the fifth chapter, an estimation model which can be used to calculate the time extensions of public projects is tried to obtain. With this direction the scope and the boundaries of the research were determined, by examining the other researches about the subject, the differences between this study and the previous ones tried to indicate. The method applied to this study was described and the examined sample group, the data collecting and analysing of the data were explained.
Description: Tez (Doktora) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 1998
Thesis (Ph.D.) -- İstanbul Technical University, Institute of Science and Technology, 1998
URI: http://hdl.handle.net/11527/16655
Appears in Collections:Yapı Bilimleri Lisansüstü Programı - Doktora

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