Limitations
work
This initial use of the small digital computer pointed to two limitations only. The first is that it is not ad- vantageous in
of "one-off" The time spent by the archi- tect's technician in producing a pro- gramme may be equally spent in doing the actual work manually for tasks where no repetition is involved.
nature.
The second limitation is implied in its name. Since it is a small digital- computer, its capacity to receive in- structions and its storage capacity is limited in quantity. Callow found it frustrating to be forced to break down construction elements of a building into relatively small compartments for purposes of writing programmes.
It proved quite possible, computer- wise, to produce finished bills of quantities, together with a schedule of building materials components (from which a contractor could order), labour components, current and fore- casted costs of materials, labour, con- tractor's overheads, insurances, and profits. These comprehensive results could be obtained by only operation of feeding in the quantity surveyor's variables of dimensions.
i. The study and analysis of building costs in contracts be- tween the years 1957-1967. ii. Forecasting recurrent main- tenance costs, compounded an- nually both in materials and labour rates, with yearly results for the next 20 years. iii. "Optimized" a selection of floor finishes by consideration of predetermined values (appear- ance, wear, comfort, cleanliness, cost, etc.) against a selected requirement.
iv. Computed thermal insulation values for a large range of thicknesses, combinations and juxtapositions of different build- ing materials, situated in
ACTION
BY TYPIST
various micro-climatic condi- tions (together with compara- tive costs).
It is not difficult to perceive the machine's possibilities in the field of acoustic design, the application to daylighting and artificial lighting, building studies, planning data, engineering calculations, and building- services design.
It is also clear that the small digital- computer, albeit in its infancy, pro- vides a tool which can be of great value to the architect, the quantity surveyor, the engineer and the con- tractor's estimator. The more it is developed. the more simple and ef- fective it will become in answering the initial need.
-
No. 1 (of At () this The second
The first variable (S1), being the 50 feet dimension of Area Figure 1), is entered into the "immediate memory" (Register 'M'). is automatically transferred to the "executive" lobe (Register 'A'). variable (S2) is fed in; this is the 20 feet dimension of Area No. 1. At (X), 50.00 is multiplied by 20.00 and the result stored in 'A' and also in Register 'R'. (The computer has a manual selective setting for decimal places for storage in 'A', but the full result up to 15 decimal places is stored in 'R' for accuracy of computation.) one
(B/) exchanges the contents of memory register 'B/' with 'A', i.e. 1,000 square feet (feet super) which is the area of hardcore and concrete for Area No. 1. This area could as easily be stored as yards super, if so desired. (B) restores the digits '1,000' to 'A' at the same time retaining the same figures in 'B'. The third variable (S3) is fed in. This is the 9 inch depth of the hardcore, i.e. 0.75 feet. At (x) the 1000 is multiplied by (S3) and the resulting 750 divided by the programmed constant for 27 cubic feet per cubic yard. The resultant cubic yardage of hardcore is transferred to 'B' by (E) and restored to 'A' by (B↓) as 27.77. This figure is multiplied by the constant for 1.25 tons per cubic yard of hardcore and the resulting 34.71 tons exchanged with 'C' by (C/ ) leaving the former zero content of 'C' in 'A'.
However, due to the limit in the number of storage "lobes" of the small computer, it was necessary to break down the results into small
groups, e.g. Compartment 1: Area of concrete
as new
sub-floor and volume of concrete in sub-floor + content of com- ponent materials (cement, sand, large aggregate, water), Compartment 2: Current costs of component materials (this entail- ed manually feeding in results from Compartment 1 variables in a second programme). Compartment 3: Contractor's over- heads and contractor's profits (this entailed feeding in results from both Compartment 1 and Compartment 2 in new variables in a third programme.) Compartment 4: Forecasts of all costs in Compartments 2 and 3 (this entailed feeding in results from Compartments 2 and 3 as new variables in a fourth pro- gramme).
These four changes of programme were necessary for every construction element and the task demanded good management and strict co-ordination of the human work (which is the most fallible link in the chain of operations).
A larger computer could carry out all the above compartmented tasks in one operation. It would not then be, however, a “small” computer with the advantages already mentioned.
Possibilities
The more one uses the desk-top machine, the greater the challenge it presents, leading the operator's im- agination to newer and wider pos- sibilities of its application.
In no great depth the authors applied it to:-
Far East BUILDER, May 1968.
Thus registers' contents are:-
'B/' = Area of hardcore (in feet super) 'B' = Volume of
(in yards cube) 'C/'
(in tons)
J
=
Weight of
"
At this stage the contents of 'B/' are brought into 'A' by (B/), exchanged with 'C' (so that future additions from Area Nos. 2, 3, 4 and 5 could be added independently for concrete areas irrespective of hardcore) and with 1,000 remaining in 'C', these same digits are brought down into 'A' by (C). The last variable (S4) is fed in, this being the 6 inch depth of concrete sub-floor. (X) multiplies 1000 by 0.5 resulting in 500 (cubic feet) which is converted to 18.51 (cubic yards) by reuse of the constant. This result is then stored in 'D/' by (D/), returned to A by (D/), and multiplied by the constant of the tons of cement per cubic yard of concrete of 1:2:4 mix. This weight of cement is stored in 'D' by the exchange of 'A' with 'D' at (D) and the volume of concrete figure then brought again into 'A' by (D/↓). In turn this volume is multiplied by the constant of the tons of sand per cubic yard of concrete, the result being stored in 'E/'. 'D/' is again entered and the process repeated to find the weight of large aggregate; the figures for which being stored in 'E'.
Lastly the volume of water (in gallons) for the designed water/cement ratio of 0.57 is found in like manner and the result retained in 'A'.
The machine then auto-matically prints the tabulated results as follows:-
Footnote:
K
SSSSS
V
50
20
0.75
0.05 1000.00 27.77
34.71 1000.00
18.51
4.27
9.49
17.26
544.19
PELUDOLEA
One of the defects of the current system of preparing quantities is that the This means original measurements become "buried" in the presented totals. that any alteration to the original data presents the quantity surveyor with an operation which, although in no way difficult, has a high nuisance value. For example, if the architect decides that in a series of twenty manholes (which have already been taken off and estimated) the heights of manholes numbers 1 to 6 will be increased by 6" in each case, that the concrete bases of manholes of numbers 12 and 13 require to be 9" in lieu of 6", and that engineering bricks should be used in the last three manholes, the quantity surveyors can make the adjustments to the estimate only by carrying out a time consuming number of small calculations. The advantage of the computer is that these calculations can be done at high speed
and part of the work carried out by staff
on lower pay scales, as indicated above.
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