![]() |
#1
|
||||
|
||||
![]()
On NZ's West Coast heavy rainfall has washed away a 30 year old Bailey Bridge. The bridge crossed the Waiho River, the stream flowing from the Franz Josef Glacier.
Due to Climate Change, or not, the Glacier has retreated a couple of kilometres in the past few years and deposited a huge amount of gravel and boulders in the river bed. Since the early 1980's, the riverbed of the 18Km long river has filled with gravel and risen 6.5m, altering the floodpain and where storm runoff can escape. It is now channelled under the bridge. On 24th-25th March, a storm brought 1086mm of rain in 48hrs (over 40 inches!), flushing the Franz Josef valley and rolling bouders down the river bed. With 8.2m of water under the bridge over a 200m width of riverbed, the forces on the bridge were massive. Despite this, the bridge withstood the force of water and boulders, but was ultimately destroyed by the north riverbank being scoured away. Instead of just dropping the 1 span that was supported at that end, the strongly connected design of the Bailey Bridge dragged 4 spans into the river. https://www.stuff.co.nz/national/111...of-destruction In view of that excellent performance, the new replacement will be another Bailey Bridge, to be built by the Army! https://www.stuff.co.nz/national/111...s-waiho-bridge |
#2
|
||||
|
||||
![]()
Impressive, to say the least about the rainfall, and the durability of the bridge.
H.
__________________
Regards, Hanno -------------------------- |
#3
|
|||
|
|||
![]()
Reliable virgin British steel!
Building long spans across gravel floodplains is just plain risky. Channels form for 10,000 reasons and flow patterns are unpredictable. The engineers ought to have put in more support piers and more expansion joints. Connecting the entire span (IMHO) is what caused so much of this damage. But, Baileys are cheap and very easy to assemble. They require next to zero maintenance and every year of service after the first is a bonus.
__________________
Terry Warner - 74-????? M151A2 - 70-08876 M38A1 - 53-71233 M100CDN trailer Beware! The Green Disease walks among us! |
#4
|
|||
|
|||
![]()
I suspect the lack of additional piers was the increased risk of flood uprooted tree hang ups.
|
![]() |
Thread Tools | |
Display Modes | |
|
|
![]() |
||||
Thread | Thread Starter | Forum | Replies | Last Post |
Bailey bridge book | Mike Kelly | The MLU Sappers Mess | 26 | 26-07-15 11:42 |
bailey bridge website | wim sikkelbein | The MLU Sappers Mess | 9 | 09-06-15 16:27 |
Wanted: 1/6th scale model Bailey Bridge parts | Pete M | For Sale Or Wanted | 16 | 01-10-12 17:48 |
Bailey Bridge question | Robin Craig | The MLU Sappers Mess | 4 | 30-09-09 06:46 |
Bailey Bridge across the Chehalis River | sapper740 | The MLU Sappers Mess | 12 | 19-04-09 18:43 |