XXX
XX
Gotta love this vintage pillowcase
celebrating the opening of Sydney Harbour
Bridge. I picked it up an an estate sale in
California years ago.

Tynan Peterson
XXX
Here is the follow-up to my answers to the Sydney Harbour Bridge puzzle.  It was fun
to do this and in the process I learned much more than I expected about a very familiar
structure that today is largely taken for granted in Sydney.

On seeing the picture first up, I recognised it what it was immediately and thought the
remaining answers were easy.  After all, the workers were at the top of the harbour
bridge (weren't they?) and that height should be easy to find.  And surely that was
Bennelong Point, present site of the Opera House, with ferries at Circular Quay in the
bay to the right.  So the view had to be to the east.  But then I looked again and realised
that the dimensions of the bay were quite wrong for Sydney Cove.  Plus I should be
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Quiz #474- May 3, 2015
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1. What is this momentus event?  What date?
2. About how far above the water are the workers?
3. In about what direction was the photographer facing?
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UPCOMING EVENTS
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Answers:
1.  Closing the arch on the Sydney Harbor Bridge, August 19, 1930.
2.  About 377 feet.
(Note the workers are not at the top of the bridge,
they are standing on the lower chords of the bridge.)
3.  North of west towards McMahon's Point.
Comments from Our Readers
Hi Colleen, lovely puzzle! I will send an email separately that gives my path to
obtaining these answers. That will allow me to insert explanatory pictures plus
some URLs as hyperlinks. Thanks for your response to my solution for the Luna
puzzle.
Megan Nielsen
Hi Fearless Leader. Another very interesting quiz for this week. This is a photo of
the Sydney Harbor Bridge at the time of the closing of the arch - 19 August 1930 -
a very momentous occasion!!!!!!!!!! The workers are way up in the air above the
water - 463' above the water. Not for the faint-of-heart!!!!!!!!!!!!!!!!! The
photographer was facing northwest toward McMahon's Point Wharf.

What do you suppose the workers got paid for this work?  
Grace Hertz
Probably not too much!

I read that one Irish guy fell off the bridge into the harbor.  He survived with
broken ribs.  The impact was so strong that his boots split and were found up
around his hips.

They gave him a gold watch and he was allowed to retire.

-Q Gen
 
My ribs hurt just from imagining this man falling off the bridge into the water! NOT
much fun!!!!!!! I'd want to retire after that kind of experience and I'd want more
than a gold watch.
Grace Hertz
Thought this might be another Australia picture and possibly the Sydney Harbour
Bridge. So I googled images for "Sydney Harbour Bridge Construction" and found
the photo. Found info at
myplace.edu.au.
Tony Knapp
And we appear to be once again in Sydney (after Luna Park) Is this in any way
homage to Savannah Guthrie from NBC's today Show who has trekked
back this week to the place of her birth?
John Pero
I was all set to start looking at pictures of bridges around the world.  I forget the
exact words I started typing into Google when a list of possibilities came up for me
to choose from.  The second I saw the word Sydney, I knew which bridge I was
going to look for.  This is the closing of the arch in the center of the Sydney Harbor
Bridge.  The arch was closed at 10 pm on 19 August 1930.  How much before that
time this picture was taken is unknown, but it couldnt have been too much earlier.  
The arch is 134 meters, or 439.6 feet, above the harbor.  This would be a major
reason why bridge worker would never have been an occupational choice of mine.  
The photographer was facing west and a tad bit north when he took the picture.  
That is the McMahons Point Wharf we see in the background.  The Sydney Opera
House wasnt built yet, but had it been it would have been just behind the
photographer.  The bridge has a nickname, it is sometimes called the Coat-Hanger.
Carol Gene Farrant
Total cheat. Kept up the Australian theme in mind and the structure looked like last
week's answer. So a quick search for Sydney Harbour Bridge Construction
was all that was needed. First link clicked
(
www.myplace.edu.au/TLF_resources/R3352/description.html) provided
answers 1 and 2, and the hint (Blues Point) for the third.
Ida Sanchez
I always learn so much from you.  Australia is on my bucket list but so far my
loving H. is not anxious to go there.  Thank you.
Winnifred Evans
Yes, I see it now, I should have paid attention to the shadow. It didn't even occur
to me. I'm slipping. LOL Plus I have never been good with directions of any type
so not surprised I was wrong with my guess.
Cindy Costigan
I also have a particular affection for the opera house.  They were building it when
my family lived in Sydney, and I got a tour of it when I returned to Australia in
1988 with the USC Marching Band.
Janice M. Sellers
Well I knew they where on the "coathanger" so they were between 49 and 134
meters. And if it were a hot day, they'd be a few centimeters higher!
Tynan Peterson
Believe it or not, I hit this one instantly, after striking out last week (I didn't connect
the bizarre and somewhat spooky face with an amusement park -- I thought it
looked Asian, for some odd reason).

I guessed it was a bridge over water, and I knew you were in Sydney recently, so I
googled "sydney harbour bridge construction" and of course, your photo was at the
top of the page. The rest of the data was easy to find on the interwebs.
www.myplace.edu.au/TLF_resources/R3352/description.html
Collier Smith

Congratulations to Our Winners!

Robyn Cook                Gus Marsh
Roger Lipsett                Megan Nielsen
Tynan Peterson                Brett Robinson
Daniel E. Jolley                Jon Edens
Liz Pidgeon                Collier Smith
Tony Knapp                Anthony Knapp
John Pero                Janice Sellers
Carol Gene Farrant                Ida Sanchez
Edna Cardinal                Judy Pfaff
Ellen Welker                Cindy Costigan
Winnifred Evans                Margaret Paxton
Rebecca Bare

Grace Hertz and Mary Turner
The Fabulous Fletchers!
**********
XXX

Collier Smith's Solution to the Puzzle
1. Closing the arch of Sydney Harbor bridge, sometime
before 10 pm on 19 August 1930. (That was 2 months after
mid-winter, so apparently the closure would have been completed
in the dark.)

2. The centerline of the lower main arch beam is 18 meters lower
than the top of the arch, at 134 m. above mean sea level (aMSL)
(see drawing/poster below). Hence, the two workers standing on
that beam would be standing at about 116 m. aMSL (or 380ft
aMSL), assuming the water is at MSL.
architecturalprints.com.au/shop/posters-prints/...

3. He was facing about 20 to 25 degrees N of W (i.e., about
WNW). (Determined by protractor on Google map from center
of span to Blues Point tower.)
www.myplace.edu.au/TLF_resources/R3352/description.html

Collier Smith
Click on thumbnail for interactive blueprint of Harbor Bridge.
Description

This is a black-and-white
photograph, taken in 1930,
measuring 18.3 cm x 25.2
cm, of workers closing the
arch in the centre of the
Sydney Harbour Bridge,
New South Wales. Below,
ferries are going to and
from McMahons Point
Wharf, where others
are docked. Jetties, terraced houses and some other buildings can be
seen among the trees on Blues Point.
Educational value

This asset depicts workers closing the gap to complete the arch of the
Sydney Harbour Bridge, which spans 503 metres - the arch was finally
completed at 10 pm on 19 August 1930; during the next nine months,
steel decking was hung from the arch to support the deck; the Bridge
was opened on 19 March 1932 by Premier John Thomas Lang.

It shows part of the Sydney Harbour Bridge, called the 'coat-hanger' by
some - after the First World War, Dr John Job Crew Bradfield and
officers from the NSW Department of Public Works prepared a general
design for the Bridge and the state government contract was let to
English firm Dorman Long and Co; over the next eight years, 1,400 men
worked to build the Sydney Harbour Bridge, supporting each half-arch
with 128 cables; prior to its opening, 96 steam locomotives were used
on the Bridge to test its load capacity; the £4.2 million construction cost
was not paid off until 1988.

It gives an indication of the height of the Bridge - the arch reaches 134
metres above the harbour, with 49 metres' clearance below its deck to
enable ships to pass underneath.

It includes some of the ferries that operated from McMahons Point
Wharf on the western side of the Bridge - before the Bridge opened,
ferries provided the only direct method of transport between Sydney's
northern and southern shores; a similar ferry service operated on the
eastern side of the Bridge, carrying passengers between Milsons Point
and Bennelong Point, where the Sydney Opera House now stands.

It shows Blues Point, which was originally granted to West Indian
convict Billy Blue in 1817, after he established Sydney Harbour's first
ferry service using a rowboat; Blues Point, now a reserve, is a popular
vantage point for people viewing the Sydney Harbour Bridge.

It was taken by Australian photographer Henri Mallard, who gained
permission to photograph construction work on the Sydney Harbour
Bridge from vantage points on the Bridge itself - a regular visitor to the
Bridge between 1930 and 1932, Mallard recorded the building process in
hundreds of photographs on glass plate negatives and also produced
some moving images.

Copyright:  Reproduced courtesy of National Library of Australia
Creator:     Henri Mallard, photographer, 1930
Identifiers:  National Library of Australia
               number nla.pic-an25009696
TLF resource R3352
Source:      National Library of Australia
               
www.nla.gov.au

About This Week's Picture
www.myplace.edu.au/TLF_resources/R3352/description.html
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seeing warehouses lining the shore and on
the point I should be seeing Fort
Macquarie tram depot which replaced the
original Fort Macquarie and which in turn
was replaced by the Opera House.  Here
is a picture from the same time, looking
east and, although the angle doesn't show
Circular Quay, you can just make out the
tram depot tower and the warehouses
beyond the almost closed bridge.

And here is another picture taken at an
early stage of bridge construction where
you can see all of Sydney Cove, including
the Customs House which is still there.

Hmmm ... in that case I must be looking
at Blue's Point and the ferries must be at
MacMahon's Point wharf with a car ferry
off to the left.  Which of course is
correct.  

And, had I seen the newspaper report of
the occasion earlier than I did (see below
right), I would have learned that the
closure occurred at 4pm.  Which means
the photograph was taken when the sun
was in the west and, since the figures are
in silhouette, the camera must be pointing
west. So even without the view to the
water below it is possible to deduce the
direction.  But there's more.  The
newspaper reports that "the lower chords"
were joined.  And this is key to the
answer to the second question.

We can see in the photograph that there is
bridge structure that rises above the
workmen.  They therefore cannot be on
the very top of the bridge.  So what is a
"chord" in this context?  With the aid of
two articles written for popular
engineering journals I was able to learn all
about chords plus get the measurements
needed to calculate the height of the
workmen above the water.  I found these
at
www.railwaywondersoftheworld.. and
www.autospeed.com.
au/cms/A_111458/...

The basic structure of the bridge involves
four arches, two on the east and two on
the west, known as the upper and lower
chords.  (I think the term chord is applied
because these arches are not true curves,
even though they look to be so.  They
actually consist of successive straight
sections (i.e. chords) that join points
spaced along the required curve).  The
two lower chords are the key structures
and are anchored at four huge hinges, two
each at the base of the north and south
pylons.  The upper chords are not joined
to the pylons but serve, along with all the
trusses etc to keep the lower chords in
place and stable.  So clearly, when the
two cantilever halves of the bridge were
joined, that join had to be between the two
sets of lower chords coming from each
side.

That was precisely what happened.  And
what we see in the quiz picture is the
second join.  The first join was of the
eastern lower chords and this is shown in
the following picture.
www.theageshop.
com.au/sydney-harbour-bridge-1930-
fairfax-archives

We are not told that this picture is of the
eastern join, but it has to be, and this is
where Henri Mallard must have stood to
take his picture of the second western
join.  His vantage point is shown in the
picture below, entitled Lower Chord
Centre Joint - East Truss. On the right we
can see the warehouses of Sydney Cove
below and the curve of Farm Cove
beyond. NSW State records does not tell
us who is in the picture (Bradfield surely
has to be there) and there is no
photographer credit, but it was likely
Mallard and he must have been standing in
an even scarier place to achieve [the shot
below right].

As can be seen from the first picture in
this sequence, the upper chords were not
joined until sometime later. This doubtless
happened with far less celebration and
publicity than occurred for the crucial
joining of the lower chords that brought
the two halves of the bridge together and
proved the extraordinary accuracy of the
alignment.

So now to calculate the height above the
water for the workers joining the lower
chord (not a safety harness in sight!).  I
saw four ways of doing this.  First, with
a face-on picture of the bridge, I could
use the known height of the pylons as a
ruler and measure the distance from water
level to the top of the lower chord at its
midpoint.

Alternatively I could take the known
height of the midpoint of the upper chord
and use my pylon ruler to measure the
distance to the lower chord below. Given
the possible visual distortions and the fact
that midpoint height varies with
temperature that seemed risky. But those
methods might have to do if I couldn't use
methods three and four.  These depended
on finding better specifications than are
available in tourist blurbs. Luckily the
measures I needed were set out in the
engineering magazine articles referred to
above.  Using these I was able to calculate
the required height as follows:

Working upwards:  The height of the
hinges on the pylons above mean water
level is given as 27.5 ft.  The height of the
lower chord midpoint above the hinges is
given as 350 ft.  Adding these (and
Fort Macquarie Tram Depot
en.wikipedia.org/wiki/Fort_Macquarie_Tram_Depot
Customs House Sydney
en.wikipedia.org/wiki/...
MacMahon's Point Ferry
www.flickr.com/photos/state-records...
Newspaper Article on
Closing of Lower Chords
19 August 1930
trove.nla.gov.au/ndp/del/article/4106890...
Upper and lower chords and crane.
www.autospeed.com.au/cms/gallery/article.html?a=111458&i=12.
Eastern Join
www.theageshop.com.au/sydney-harbour-bridge-1930-f...
Lower Chord Centre Joint - East Truss
nvestigator.records.nsw.gov.au/asp/photosearch/photo.as
Bridge dimensions can be found at
www.autospeed.com.au/cms/A_111458/printArticle.html
assuming that the lower chord height is to its top surface) gives a total of 377.5 ft.

Working downwards: The height of the bridge is widely available and is given as 134 m
(440 ft). The depth of the upper chord (throughout) is 3.3 ft and the length of the
vertical truss at the crown is 60 ft.  Subtracting these two measurements from 440 ft
gives 376.7 ft.  

Not spot on, but I can live with that and say 377 ft.  The order of accuracy of the
component measures is not clear, so I am not giving a +/- as a good physicist should.  
Besides which, the midpoints of the arches rise with temperature as the metal of the
bridge expands (hence the importance of the hinges). August is winter in the southern
hemisphere, so the measures are not likely to have been greatly affected by temperature
on the day in question.  Nevertheless, it is recorded that when the join was made
(doesn't say whether it was the eastern or the western one), there was perfect
horizontal alignment horizontally but a small vertical mismatch that was attributed to the
northern cantilever having received more sun on the day.

So, there we are.  Puzzle solved, I think.  And I might have saved myself some trouble
as far as the direction of the camera was concerned.  As an afterthought, and out of
curiousity, I did a google image search on the puzzle image and immediately came up
with
www.myplace.edu.au/TLF_resources/R3352/....  I wonder how many solvers
went directly to that!  Of course it didn't help with the question of height and, since it
gives the 134 m (440 ft) statistic, it may have misled.
Finally, I can't resist adding some links to the story
of Billy Blue from whom Blues Point gets its
name.  He was Sydney's first ferryman and is
written up in the Australian Dictionary of
Biography. But there are more evocative accounts
given by historian Cassandra Pybus at
press.anu.edu.au//anu_lives/transnational/... and
www.themonthly.com.au/issue/2012/april/...

Early Sydney had many notable characters, but
Billy Blue has to have been one of the most
extraordinary.  If you want to see what sits on his
point today go to
sydneyphoto.blogspot.com.au/2006/01/...l and be
prepared to see one of Sydney's ugliest buildings,
complement to the beautiful one peeping through
under the bridge.
Billy Blue
adb.anu.edu.au/biography/blue-..
**********