الفهرس | Only 14 pages are availabe for public view |
Abstract Globally, various studies have revealed that the wealth of any nation is gauged by its performance in infrastructure provision through its construction industry, specifically highway infrastructure. Hghway infrastructure is the backbone of economic and social growth of any country. For an optimal economic return, highway infrastructure projects have to be delivered with reduced cost, on time and in accordance with technical specifications. Over the last 50 years, the ”iron triangle” consisting of cost, time and quality at the three vertices has become inextricably linked with measuring the success of project management. This is perhaps not surprising, since over the same period these criteria have usually been included in the description of project management. Despite the importance of the highway projects and their impact on the national economy, the highway network in Egypt is suffering from construction defects and short-term pavement performance problems. Furthermore, concerns are raised frequently on the poor performances of these projects in Egypt on time and cost accounts, with directly subjected the construction of these projects to delay and cost overrun. For that, it is of key importance to accomplish a study on highway projects in Egypt in order to determine the sources of these problems as well as suggesting recommendations for overcoming the negative implications of these issues. The main purpose of this thesis as mentioned in its title is to identify the factors influencing quality, time and cost of the highway construction projects in Egypt. Therefore, the first objective of the current study is to identify the factors which can adversely affect the performance of the quality, time and cost. Furthermore, specifying the effectiveness degree of the identified from the perspectives of the owners, consultants and contractors. In the present study 41, 38 and 26 factors have been identified to measure their effect on the performance of the quality, time and cost respectively. By analyzing the viewpoints of the owners, consultants and contractors regarding the factors influencing the quality, time and cost through the application of fuzzy triangular membership function, it has been noted that ”availability of experienced staff in the owner’s and contractor’s teams during the project execution” is the most critical factor affecting the quality of highway projects in Egypt. While, the top significant factors affecting the time and cost performance and leading to schedule delay and cost overrun are the ”contractor’s technical staff is insufficient and ineligible to accomplish the project” and ”inadequate preparation of the project concerning planning and execution” respectively. The second objective of the study is to develop models which can be used by the construction parties of the highway projects in Egypt for predicting the percentages of quality level, delay and cost overrun through the application of regression analysis method and statistical fuzzy approach. The validity of the developed models with respect to the two methods has been checked and it has been showed that the statistical fuzzy based model shows prediction accuracy better than linear regression based model in predicting percentage of quality level. While, the linear regression based model shows prediction accuracy better than statistical fuzzy based model in predicting percentages of delay and cost overrun. The third objective is to present a methodology for improving and assessing the performance of highway projects in Egypt. The developed methodology has adopted the AHP method to identify the most important factors and measures of success in order to improve and assessment the highway projects performance in Egypt. Three hierarchical models have been presented, these models are: a) ”the hierarchy model of the success factors according to the project objectives”, b) ”the hierarchy model of the success factors according to the project execution phases” and c) ”the hierarchy model of the success measures”. The last objective of the study is to develop a new contractor adjustment factor (C.A.F) for highway construction projects in Egypt that depends on the actual quality of the constructed pavement through the application of KENLAYER software and comparing the results obtained from this method with the results of the Egyptian Code for Urban and Rural Roads for determining contractor adjustment factor in order to show the fairness of the developed method. By comparing the results obtained from the suggested method (C.A.F) with the results of the traditional method of the Egyptian Code for Urban and Rural, a noticeable difference between the two methods is observed. This difference is due to the C.A.F depends on the performance of the whole constructed section while the traditional method depends on the performance of each layer separately. Therefore, it is recommended to replace the traditional method with the C.A.F method because it considered the pavement cross section as one unit. |