UBC Theses and Dissertations
Computer aided cost estimation of steel structures a case study of operational approach Shing, W.Y. Albert
An arrangement has been set up between the University of British Columbia and an industrial firm ,Coast Steel Fabricators, to investigate the topic of computer cost estimation of steel structures. The objective of this research is to computerize the current cost estimating process of Coast Steel Fabricators and investigate a method of generating the labour hour variables used by the estimating program. This research has made the following contributions: A computer estimating program was developed using the operational approach and a method was investigated to generate the labour hour variables required by the computer estimating program. The unique arrangement between this study and the industrial firm has proven to be successful. Coast Steel Fabricators updrated their estimating process and achieved a higher efficiency. The author was given hands-on experience and free access of the data files throughout the study. The computer cost estimating program is written in Basic and runs under the MAI-Four computer system. The program is menu-driven to allow the users to: 1. store labour hour variables; 2. enter inputs from take-offs; 3. compute the labour hours and material weights; and 4. calculate the labour cost, material cost and total cost. Coast Steel Fabricators reported that the computer cost estimating program has reduced the overall estimating time b y 30%. The labour hour variables are defined as the time for each operation. As these variables are vital to the computer estimating program, a method has been developed to obtain these variables by collecting shop data at a global level through an information system. The global shop data will then be analyzed by the technique of Multiple Linear Regression (MLR) using a spreadsheet program (Lotus 1-2-3). An optimun size of 200 observations was recommended to give a monthly average. The program is also menu-driven to allow the users to: 1. convert global shop data into piece files; 2. sort the piece file into component files; 3. perform MLR analysis on the component file to obtain the labour hour variables; and 4. plot the standard error of each labour hour variable. The labour hour variables will serve as a powerful tool for time studies in case of the start-up of a new fabrication plant and will provide feedback to the cost estimation program of an ongoing fabricator. Since the applications are written in the Basic and spreadsheet environments, programs can be easily customized for use by a number of steel fabricators.
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