Bridges &c.

[Kirbstone]

Moving over from Jack's Track I'll say a little about 'The technology at the Time' with regard to same.......Stone.

At Boyle, Co. Roscommon we have probably our oldest bridge still carrying modern traffic. The round arches are small, spaced between thick piers and built of durable stone.
That bridge dates from 1190 or thereabouts and has 5 arches.

Rs Abbeytown Bridge, Boyle.jpg

Nearer to me, spanning the River Barrow is Leighlinbridge, (pronounced Locklinbridge) which has nine larger arches, slimmer piers and dates from 1320. The Black castle beside it is from 1189. This bridge was subtly and sympathetically widened in 1789 and you'd have difficulty now finding the evidence. Again the arches are round.

black_rock_castle Leighlinbridge.jpg

Around the same time the 'Newbridge' was built crossing the Thames in Oxfordshire and this bridge has elegant pointed arches on the six main 14th Century spans.

Newbridge, Oxforeshire Thames.jpg

The inland waterways canal era kicked off in the late 1700s and most bridges now sported the 'catenery' optimal stone/brick load-bearing shape. This little 1848 bridge in Boyle shows this arch shape.

Tom.

[Kirbstone]

Boyle Town Bridge

Boyle town river bridge.JPG

T.

[Kirbstone]

I'll re-open this thread (excuse the pun) with the theme, openable bridges.

Answering Carl's info. on 'Pics & Looks' about the software glitch associated with Dublin's Calatrava swingbridge, I hadn't heard anything about that. I suppose nowadays it's inevitable that some computer control is built into such mechanisms.
Some years ago I visited Tower Bridge in London, Victorian mega-engineering well over 100 years old, not a computer in sight and working superbly.

I suppose the people looking after Dublin's movable bridges must exercise them on a regular basis to ensure continuing maintained function. They are all relatively new and should last generations/centuries.
Bridge 1 when coming in from the sea is the '80s Eastlink single bascule bridge, designed by engineers with accountants looking over their shoulders and styled by some lorry driver on the lack of an envelope. A functional graceless facility only.

800px-EastLinkBridge.JPG

Bridge 3 is quite near Gandon's Costoms House, has twin 'basket' swinging sections and is for pedestrians & cyclists only. Also pretty graceless.

BSean O'Casey pedestrian swingbridge Dublin.jpg

Bridge 2, between the former two is the amazing Calatrava creation' the Samuel Beckett Bridge, for which he should be beatified. It serves to draw the eye of our docklands visitors away from the glass boxes on the quays either side, which must be a good thing.

800px-The_Samuel_Beckett_Bridge.jpg

Tom

[skirted_in_SF]

Calatrava also designed this bridge which is closer to me:
https://encrypted-tbn2.gstatic.com/imag ... O66Dn9d5ug
Pedestrian and bicycle only, it spans the Sacramento River in Redding CA. Mt Shasta is in the background of this shot.

It has been mentioned that the Dublin bridge pivots. I assume it pivots from the base of the tower.

[Kirbstone]

Stuart,

Interesting bridge and very like the Calatrava one in Seville crossing the Gunderquiver at one end of the rowing course there, with the main support beam reversed, so to speak.

The Beckett Bridge does indeed swivel on a 'mushroom' under its ascending arm and centre of gravity. It's a dual carriageway plus pedestrian & cycle lanes as the pic. illustrates.

Tom

[skirtyscot]

Wow! How long does the traffic have to wait for that to open and close?

[Kirbstone]

SkS, Fortunately there are other bridges not far away in both directions, so a detour could be made in less time than it takes to wait for it to swing back.

I've never seen it swing myself, but have watched a clip on U-tube. It takes about 12 mins. to reach fully open, say 15 mins. for boats to pass plus 12 mins to close, so you're looking at close on 40 mins altogether, certainly more than half an hour. The good news is that they probably only open it once a month, if that.

The alternative bridges are only a few minutes drive away, anyway.

Tom

[crfriend]

I've never seen it swing myself, but have watched a clip on U-tube. It takes about 12 mins. to reach fully open [...]

That seems long, but we are talking a fair amount of mass here. I'd love to be there to see it work.

On another note, I think I've been transferred to Ireland -- at least the weather feels that way. It topped out at about 12 degrees Celsius today at 98% humidity and then went downhill from there to about 9 C and 100% -- a standing drizzle (what we know here as an "Irish Hurricane"), which is an entirely unpleasant affair altogether.

By the time came to go home, I wound up putting both the heat and A/C in the car on -- the A/C to dry things out a bit and the heat so I wouldn't catch a chill. The upshot of this is that the vegetation will grow like mad in the next few days. (There's a reason that Ireland is known as the "Emerald Isle".)

[skirted_in_SF]

-- a standing drizzle (what we know here as an "Irish Hurricane"), which is an entirely unpleasant affair altogether.

In the three and a bit years I lived there I started calling those conditions Seattle Sunshine.
The Seattle Times used to publish a wrap-up of the the previous month's weather the first of the following month. There was one December when the sun did not come out a single day.

[Big and Bashful]

There is a swinging footbridge across the Clyde in Glasgow, I think I binned my footage of it closing unfortunately, also, it's nice, but not as pretty as those you have posted. However, going back in time to an earlier age, I would like to table a swing aquaduct, we used it years ago and saw it in action, I have some good photo's on paper. However, somebody has stuck it on YouTube, nice old mechanical technology at work:

https://www.youtube.com/watch?v=AYeFbTKE5bM

[couyalair]

Intersti g subject and good pics. I,d never even heard of the swing aqua bridge.

Martin

[Big and Bashful]

When they built the Manchester ship canal, the original brick built aquaduct was too low and obstructed the passage of ships, so they replaced it with this swinging aquaduct in the 1890's, according wto wikipedia it is unique. It's great that 120 years after it was built, this is still working and in regular use.

[crfriend]

When they built the Manchester ship canal, the original brick built aquaduct was too low and obstructed the passage of ships, so they replaced it with this swinging aquaduct in the 1890's, according wto wikipedia it is unique. It's great that 120 years after it was built, this is still working and in regular use.

I think that there's a moveable motorway-bridge that runs parallel to it at some moderate distance. I've seen pictures of it, both open and closed, and have seen pictures taken on (in?) it from a canal-boat. Good stuff.

When I look at some of the engineering works that have been done in relation to canals it sometimes makes my head swim until I remember my Archimedes and then it becomes simply a matter of containing the water.

[Big and Bashful]

There is an opening road bridge quite close to it, I think one of the wikipedia pictures shows both bridges, in the closed position though, yep, third one down.

[Kirbstone]

That Manchester ship canal swinging aqueduct just has to take first prize. No aesthetic beauty, but that wasn't the brief to the designers. What fascinates me is the seal to allow both gates to open, narrowboats to pass and not much water lost.

I was miles out in my estimate of the time taken to open the Beckett Br. in Dublin....2-3 minutes is nearer the mark.

Tom.