İnşaat Projelerinde Gecikmeye Neden Olan Faktörler: Bir Sentezleme Çalışması

Abstract

Gecikme; bir inşaat projesinin istenilen süre zarfında tamamlanamaması durumudur ve proje tarafları için önemli kayıplara neden olmaktadır. Geçmişten günümüze her geçen gün karmaşıklaşan projelerde gecikmeler projenin başarısı üzerinde negatif etki yaratmakta; süre, maliyet ve kaliteyi olumsuz yönde etkilemektedir. Bu yüzden günümüzde gecikmelerin önceden tahmin edilebilmesi ve ek maliyetlere, süre uzatımına gerek kalmadan sorunların çözülebilmesi için hayati önem taşımaktadır. Bir inşaat projesinin başarılı ile sonuçlandığının kabul edilmesi için, planlanan bütçe/süre içerisinde, üretilen çizim ve şartnamelere uygun ve proje paydaşlarını memnun edecek şekilde tamamlanması gerekir. Çeşitli çalışmalar; kalite, güvenlik, maliyet aşımı, süre aşımı, verimlilik gibi gecikmeye neden olan başlıkları incelemesine rağmen, bu çalışmalardan çok azı inşaat projelerinin ortak ve genel sorunlarını tartışmaktadır. Gecikme nedenlerinin detaylı araştırılması için, kapsamlı ve bağlamsal bir çalışmanın yapılması gereklidir. Geniş bir literatür taraması şeklinde yapılan bu araştırmada gecikme nedenleri küresel olarak incelenerek, farklı kaynakların araştırılması sonucunda elde edilen veriler harmanlanarak genel bir çıkarımın yapılması amaçlanmıştır. Bu araştırmanın içeriği ve hedefleri sırasıyla şöyle açıklanabilir: İlk bölümde problemin tanımı, tezin amacı ve kapsamı açıklanmıştır. İkinci bölümde, inşaat projelerindeki gecikme nedenleri ile ilgili literatür taraması yapılması, gecikmelerin türlerinin incelenmesi ve sınıflandırılması yapılmıştır. Bu gecikmelerin projelerde görülen etkileri literatür taraması yoluyla incelenmiştir. Üçüncü bölüm kapsamında, gecikmelerin analiz edilmesi için kullanılan teknikler incelenmiş ve bu teknikler; planlanan gerçekleşen, etkilenen planlanan, bozulan gerçekleşen, zaman etki analizi ve pencere analizi başlıkları altında açıklanmıştır. Dördüncü ve beşinci bölümlerde ise, literatür taraması yoluyla ilgili makalelerin elde edilmesi, incelenen makale grubunun kodlamasının nasıl yapıldığının ayrıntılı bir şekilde anlatımı ve makalelerin analizi yapılmıştır. Çalışma alanı 2005-2016 yılları arasındaki 22 makale kapsayacak şekilde hazırlanmıştır. Bu makaleler daha detaylı incelenerek gecikme nedenleri saptanmıştır. Gecikme nedenleri 9 grup altında toplanmıştır. Bunlar; mal sahibi ile ilişkili faktörler, yüklenici ile ilişkili faktörler, danışman ile ilişkili faktörler, tasarım ile ilişkili faktörler, işgücü ile ilişkili faktörler, ekipman ile ilişkili faktörler, malzeme ile ilişkili faktörler, proje ve sözleşme ile ilişkili faktörler ve dış etmenler ile ilişkili faktörlerdir. Bu kategoriler altında değerlendirilmek üzere 205 gecikme nedeni saptanmıştır. Gecikme nedenlerini göstermek için Ishikawa (balık kılçığı) diyagramı kullanılmıştır. Bu derleme dökümanında, benzer ve sabit olmayan gecikme faktörlerinin sıralanması için önceki çalışmaların güncellenmiş bir derlemesinin yapılması amaçlanmıştır. Çalışma, yirmi iki makaleye göre inşaat projelerindeki gecikmelerden sorumlu faktörleri ve kategorileri içermektedir. İnceleme sonucunda, bu tür araştırmalara anlamlı cevaplar üretmek için farklı bir yöntem veya yaklaşımlar kullanılması gerektirdiği kanaatine varılmıştır. Çünkü 22 çalışmanın derlenmesiyle hiçbir çalışmanın olduğu gibi genellenemeyeceği ve doğrudan uygulanabilir olamayacağı görülmüştür. Ancak bu tez, anketler için güçlü bir veri kaynağı oluşturabilir. Bu çalışma ile potansiyel olarak anlamlı cevaplar yaratabilecek gerçek projelerin istatistiksel analizleri yapılabilir. Bu çalışma sonucunda elde edilen veriler ve ileriki çalışmalar için yaptığı öneriler sayesinde; gecikmeler konusunda inşaat sektörü için kaynak oluşturacak bir çalışma ortaya konmuştur.

The construction industry is one of a major player in the economy, generating both, employment and wealth. The delay is called a incompletion within a desired period of time. In construction, delay could be defined as the time overrun either beyond completion date specified in a contract or beyond the date that the parties agreed upon for delivery of a project. Delays happen in most construction projects, whether simple or complex. The problem of delays in the construction industry is a global phenomenon and the construction industry in Turkey is no exception. There is an increase in the number of construction projects experiencing extensive delays leading to exceeding the initial time and cost budget. Projects can be delayed due to number of reasons that may be due to the contractors’ acts, the owners’s acts, the consultants’ acts, the designers’ acts, severe external factors or any other unexpected conditions. Delays may occur early or later in the project duration, alone or with other different delays. Delays can be minimized only when their causes are identified. Many articles and studies conducted on causes of delay in construction projects, both locally and internationally have been reviewed. The content and objectives of this research can be explained as follows: In the first chapter, the definition of problem, the purpose and scope of the thesis are explained. In the second chapter, several articles have discussed causes of delay in construction projects in numerous manners; some studies identified the main causes of delay in several countries and various project types, while other studies discussed the delay analysis methods and the proposed ways to mitigate it. The literature on the causes of delays in the construction projects were reviewed discriminatingly and chronologically sequenced. Types of delays in construction sector were reviewed and classified in two categories. (1) Excusable delay as define a delay that is due to an unforeseeable event beyond the contractor's or the subcontractor's control like heavy rains, strikes, fire, client suggested changes, differing site conditions, change of government policy or their intervention, stakeholder intervention etc. Alkass S. et al (1996) says that when there are excusable delays, contractor is entitled to time extension in case date of completion is extended. Excusable delays can be further classified in compensable and noncompensable delays. Compensation delays are caused by the owner or the owner's agents. An example of this would be the drawings late release from the owner's architect. A compensable delay normally leads to a schedule extension and exposes the owner to financial damages claimed by the contractor. Non-compensable delays are caused by third parties or incidents beyond the control of both the owner and the contractor. Examples typically include acts of God, acts of government in its sovereign capacity, etc. noncompensable delays are such where both contractor and client are not responsible for delay. Under such circumstances only time extensions are granted and no monetary compensation is provided. Such delays include act of God. (2) Non-excusable delays are cause by carelessness or actions and inactions of contractors or lack of performance of the contractor on the construction project. This delay can be cause by underestimates of productivity, improper project planning and scheduling, poor site management and supervision, wrong construction methods etc. For such delays no time extensions and monetary compensation is given to contractor/subcontractor if it has affected whole duration of project. Therefore, contractor is responsible to continue their work with no entitlement to claim for extension of time or delay damages until they completed the project. The effects of these delays on the projects have been examined through literature review. If delays can not mitigate truely, construction projects come up againts some effects like time overrun, cost overrun, disputes, arbitration, litigation and total abandonment. In the third chapter, the techniques used for analyzing delays have been examined and these analysis techniques were described under the headings of (1) as planned versus as built, (2) impacted as planned, (3) collapsed as built, (4) time impact and (5) window analysis. In the fourth chapter, although literature review usually plays a part of a study in most cases, it can also be a stand-alone work. A literature review study is not merely a report on the references. Instead, this type of study synthesizes the results from individual studies to produce a coherent and integrated argument about one research subject (Fink, 2005). A recent research trend shows an increasing use of systematic review in current literature. Because a review of existing studies is often quicker and cheaper than embarking on a new study. Systematic review is a type of literature review that collects and analyzes specific and reproducible research studies or papers for identifying all the literature of a certain agreed level of quality that relate to and answer research questions. Firstly, 286 articles were found by conducting research on well-known and reliable databases. Then, a preliminary review was conducted through reading abstracts and keywords of the 71 papers and the following three filter criteria were used to further select relevant papers for in-depth review and analysis. The search is restricted to peer-reviewed papers written in English. Eleven journals with the highest numbers of papers focusing on delays in construction were chosen in order to ensure high quality of selected papers. Finally, the articles between 2005 and 2016 were included in the review. The scope of the study was limited to 22 articles. This paper reviews 22 studies around of the world, which has surveyed the delay factors and analyzed them. The analysis focused on journal title, publication year, country/region distribution, keyword analysis, the number of authors, sources of ınformation, level of analysis and total number of questionnaires distributed and response, response rate for different categories for the questionnaire. In the fifth chapter, the main purpose of this paper is to review research, which has categorized the causes responsible for time delays and cost overruns in projects. Totally 9 categories of causes were identified from the various related studies reported in the literature. These 9 categories or groups are (1) Client/Owner-related, (2) Contractor-related, (3) Consultant-related, (4) Design-related, (5) Labour/Manpower-related, (6) Equipment-related, (7) Material-related, (8) Project and contract-related, (9) External. The review undertaken in this paper covers research studies in the area of construction delay with time and cost risks. Two hundred and five (205) different schedule delay factors were identified through detailed 22 literature review visualized by utilizing Ishikawa (Fish bone) diagrams. In the last chapter, work to create resources about delays in construction industry has been revealed with data obtained in this study and its recommendations for further studies. This review paper attempts to provide an updated compilation of the earlier studies on ranking of the delay causers, which are never similar and constant for universal projects. This paper gives all the combination of factors and categories responsible for construction delays by 22 studies. From the review, it is concluded that this type of research requires a different method or approach to generate meaningful answers. Because this critical review of 22 studies also demonstrates that none of the studies can be generalised and directly applicable ‘as is’. This study can be useful for surveys and statistical analyse of actual projects could be done which potentially could generate meaningful answers. Though best efforts were put in this research and findings do make a contribution for industry, this research has some limitations. The sample size of 22 is considered to be on the smaller side for analysis. Future studies could be extented sample size for significant contribution. Work to create resources about delays factor in construction industry has been revealed with data obtained in this study and its recommendations for further studies.