the staff of the computer centres, the engineer being required only to define the problem and to supply the input data. Where possible, the computer centre will process the data making use of programs previously prepared by the user, or selected from the com- puter manufacturer's library. This avoids the considerable time and ef- fort involved in the preparation and testing of specially written programs.
For some applications, the use of a specially written program is unavoid- able and under these circumstances close liaison between the engineer and the programmer is vital. In the case of some of the consultants' work, their engineers have in fact written the pro- grams themselves
a great advantage where the system to be programmed is highly technical.
-
Once the program has been selected or written, the format for the input data can be determined. This is usually on printed forms designed to facilitate ease of both compilation by the en- gineer and transfer of the data onto the input media by the operator.
Project scheduling
On the desk-top computers, the programming and data processing is carried out in the PWD by engineers and surveyors and their assistants. Once again prepared programs are available, but staff of the Civil En- gineering Office have received training
for writing programs and have written several which are now in regular use.
One of the earliest uses of comput- ers by PWD was the time scheduling of the programme for the Waterfront Road project, using the Critical Path Method (CPM). Here they have proved a boon, for although CPM involves only simple techniques, in a large and complex network manual computa- tions become particularly laborious and prone to errors.
The Waterfront Road scheme con- sists of very many activities requiring careful co-ordination. At the beginning of the project, ferry piers had to be resited before part of the reclamation for the new roadway could be carried out and seawalls had to be constructed for the reclamation for new ferry pier concourses. At the same time, the ferry routes through the reclamation area had to be maintained until the new piers and access to the piers had been completed.
Similarly, channels had to be left in the reclamation for drainage out- falls while the existing culverts were extended through the reclamation. All of these activities had also to be phased with legal formalities, land acquisition, flyover design and construction, and flyover design and construction, and many other activities involving very close co-operation of numerous divi- sions and departments of Government.
The planning and control of this project is being undertaken by the
Civil Engineering Office and the basis of the plan is a comprehensive critical path network comprising several hun- dred activities. The network is analysed on the ICL 1902 computer using a packaged program from the manufac- turer's library. Similar computer pro- cessing is carried out, but in greater detail, on a sub-network for a complex section of the project, and this is up- dated every two or three months.
In both cases the input data is simply a list of the activities with their start and end event numbers, and a project start date. The print-out is in the form of a time schedule including every activity, with critical activities and the amount of float (spare time) for non-critical activities indicated.
Highways
Computers can be used to advantage on several steps of highway design and construction, from the initial survey and.selection of the routes to the de- sign of the piles and prestressed con- crete beams for bridges and flyovers. Computers also provide a valuable aid to the setting out of complex or dif- ficult road curves.
Road alignment
In order to obtain the most eco- nomical design for a road, various alignments have to be considered and the effect upon earthworks of each change in the horizontal and vertical
Sequence No.
IDENTIFICATION
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Input data sheet for part of the network for Waterfront Road project
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Far East BUILDER, July 1969
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$2
37