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I remember the days before computers changed our lives. When I was a lad, I first trained as a civil engineer in the late 1950s to early 1960s. There were no electronic calculators, and all calculations were performed either manually, by trigonometric tables, or by using a slide rule.

We used to analyse the stresses and bending moments in structural elements using advanced mathematics based upon first principles, knowledge of which has long faded from my aged brain. The Sydney Harbour Bridge is a classic two-pinned arch design which we studied. If you drive past both abutments, you will see the huge supporting pins which take the entire load of the bridge.

 

abutments

 

A friend of mine was a surveyor who worked on the construction of the Sydney Opera House, using the old optical tools of the theodolite, the dumpy or optical level, and the measuring chain.

The theodolite was a telescope mounted on a tripod and set exactly over a point by the surveyor using a plumb bob.

The theodolite  was able to be rotated about its horizontal and vertical axes with graduated scales, to enable the measurement of angles between two points to an accuracy of seconds of arc,which were read by the surveyor and noted manually in his field book.

Old Theodolite

Similarly, the dumpy level was an optical instrument mounted on a tripod, used to measure differences in height by means of a graduated staff carried by the surveyor’s assistant known as the chainman.

Digital dumpy level staff

The surveyor would first level the instrument using base screws to centre a bubble in both directions, and then focusing through the level, would read the staff held vertically by the chainman on a point of known level, and then by reading the staff on the next point would calculate the level of that point. Today of course, those instruments have digital readouts, but not then. All data then had to be entered in the field book by the surveyor.

The measurement across the Harbour was achieved by a theodolite using a technique known as triangulation.

Bridge length triazngulation

Two measured baselines were set up on one side of the Harbour. The theodolite was then placed over the end of each baseline in turn, and by sighting the peg at the other end of baseline first, and then the same fixed points on both side of the Harbour and reading the angles, triangles with all angles known were established, which allowed a  trigonometric calculation of distances between the points, thus permitting a calculation of the distance across the harbour.

Today, digital theodolites are used to measure distances using electromagnetic waves, consisting of bouncing a laser beam off a mirror.

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The Opera House was originally proposed with parabolic sails by Utzon, but the technology available did not allow the surveyors to locate points along the sail for placement of the precast concrete elements, unless by using extraordinarily involved calculations carried out by hand.

Coupled with the prohibitive cost of constructing the precast concrete elements for the sails with constantly changing curvature, the sail design was changed to circular, which as having a fixed centre, made the design of formwork and the location calculations for the precast elements much simpler. In my opinion, the original proposed design depicting ship sails filled with the wind was far more elegant than the present structure.

Utzon_Sydney_Opera_House.jpg

In the construction industry in which I was involved, there is what is known as a critical path, which is a chart showing the most efficient order in which to perform the different components of a construction contract, by designing a path of critical construction elements.

We had to work it out by drawing a table linking all the elements and then determining the quickest route by longhand calculations. I remember the day of days when I was working on the first phase of the Darling Harbour project in Sydney in the late seventies, when we finally used a computer-generated critical path by the use of punch cards.

It makes it hard to believe the moon landings of 1969 to 1972, and perhaps explains why no one has landed there in the ensuing fifty years.

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 By the 1980s, when I had turned to law in order to escape the Builders Labourers Union, computers arrived but were DOS based,which required keyboard entry.

All Court cases were paper based, and it took over seven years to have a personal injury case heard in the NSW Supreme Court.

Then Windows arrived, and over the years smart phones, ipads, and all of the rest of the modern technology which we have today. All filing in Court is now electronic, and I keep no paper files at all. All documents are up in the Cloud and securely backed up on an external hard drive.

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Years ago, I realised that offices were a thing of the past, and moved to my home office. All that is needed is a laptop, WiFI., and a few good software programmes. The COVID shut-downs have demonstrated the utility of home offices, and things will never be the same. Cheques and bank tellers are things of the past, and more and more banks are closing. Similarly, hand-written letters will soon be things of the past, as are telegrams, and post offices will disappear.

FingsAin't Wot They Used T'Be

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