แบบจำลองการประมาณต้นทุนเบื้องต้นสำหรับงานวิศวกรรมของโครงการก่อสร้างระบบรางคู่ / เจษฎา ศรีสกุลชัย = PRELIMINARY COST ESTIMATING MODEL FOR ENGINEERING WORK OF DOUBLE TRACK RAILWAY CONSTRUCTION PROJECT / Jessada Sresakoolchai
Nowadays, Thailand has on standard method for preliminary cost estimation. Moreover, there is no research studied about double track railway project directly so the development of preliminary cost estimating models is required. The objectives of this study consist of 3 parts i.e. exploring the significance of attributes that used to estimate preliminary cost for double track railway project, developing of the preliminary cost estimating models for double track railway project and developing of time adjustment indexes. The methodologies of each part can be explained as follow. The first part aims to explore the significance of attributes that used for calculating preliminary cost estimate, the preliminary analysis found five work components that were suitable as the representatives. The work components of railway project consist of Earthwork, Road and Structural work, Building and Utility work, Track work and Signaling and Telecommunication work. The questionnaire is used as a tool to collect data for identifying the significant attributes. The respondents were 30 experts from public and private organizations. The results found that many significant attributes were confirmed by respondents but some attributes may not be used due to the lack of data in preliminary phase. The accuracy of preliminary cost estimate can be developed if the mentioned attributes are provided in the future. The second part was the development of preliminary cost estimating models. The models were developed by Multiple linear regression, Artificial neural network and simplex optimization. The attributes were depended on the work components. The error of the cost from developed models were acceptable that provided error less than 35%. The third part, developing of the time adjustment index, the K value concept is used to develop the time adjustment indexes. However, Track work and Signaling and Telecommunication work cannot apply K concept to develop the indexes because there is no announced cost index from The Ministry of Commerce. Therefore, the development of time adjustment indexes for these works needed to apply price instead of cost index. In conclusion, this study develops the preliminary cost estimating models and the results of model present the acceptable error
