| Abstract | Up till now, computer Aided Design in water supply network design has been mainly restricted to hydraulic calculations. The available computers, whether main or micro, are Deing utilized With hydraulic design software packages. The subsequent part, which includes drawing of layout, assessing the suitability and location of fittings according to site condition at the field, bill of quantities for both pipes and fittings, is usually done manually, and hence may lead to under of over assessment of the demand. This ignored part may have impact on the performance to the system.
Now with the advent of computer graphic facilities in the recent past, the Computer Aided Graphics can be linked with hydraulic design. Ultimately this integration makes the designed phases fully computerized, thus reducing the possibilities of errors.
At present a number of such graphic programs and computer systems are available in market, which can draw figures. Recently a Computer Aided Design/Computer Aided Manufacturing (CADAM) system has been installed with the existing IBM 3031 maincomputer at the Regional Computer Center of the AIT. This interactive CADAM system has 6 graphics work stations (IBM 5080 graphics workstation) and one color pen plotter (IBM 7375 color plotter) facility. Apart from drawing geometrical configurations, the program includes a "3-D piping Module" which is able to generate 2-D as well as 3-D piping drawings including fittings, available in the catalogue of the date base, and the bills of materials.
This study has been directed towards an assessment of the practicability of the package. A Sample water-supply layout belonged to Kita City has been selected for experimenting with the package. The sample layout was drawn on 2-D geometry and pipes and fitting were inserted in the layout by using the 3-D piping module. The fittings and pipes were those, which has been provided in the catalogue, called "PROJDAT2", supplied by CADAM.
The size of network was tackled by increasing the drawing (model) computer memory size (i.e. from 5,000 words to 20,000 words). The module memory size is space of computer memory allocated for each drawing, apart from layout, the piping detail (also called spool drawing) drawings, which snow details of catalogue specifications of fittings and length of pipes, were generated in parts according to the limitations of space of the spool drawing. The fittings available in PROJDAT2 have been studied and further recommendations have been made to modify the existing items or add further items to suit specific requirements in the field. It has also been noted that spool drawings are generated in inches and feets. After drawing the layout with inserting fittings, mesh file (file in which the drawing data is in numerical form) was generated, giving details of pipes and fitting with lengths and location. The mesh file data, being lengthy and unsuitable for practical use, was further processed with FORTRAN programs after transferring the file to the other main computer "IBM 3083" and reduced to the required information.
An attempt to generate the network automatically on the work-station by feeding data through mesh file, was not successful probably due to reason, that the feed-in data to mesh file requires special formatting which at present is not well documented in the instructional/user manual and needs further to develop programs in FORTRAN for formatting the numerical data. After solving the problem, it may be possible to link the hydraulic analysis directly with the CADAM, Producing to the drawn network on the graphics work-station without keying in or digitizing again values/data at the work-station.
The study revealed a great potential of CADAM for the design of water supply networks. The program package may become a valuable tool for practical design work. one it is adjusted to specific requirements of water supply networks. |