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Whalley Bridge Incident Overkill?

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Whatever, i'e whether or not it was overkill, there was a heck of a lot said on the news and I thought they might have mentioned just once that the railway line was closed, because it's a mainline route.

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21 hours ago, tlangdon12 said:

It's not overkill. What you can see from the news footage is that the earth under the auxiliary slipway has been largely washed away by water flowing under the slipway; which should not have happened.  

Its been happening for some time according to local reports, with people saying that grass, weeds and small bushes were growing in the gaps of the concrete slabs of the spillway.

 

This dam has been neglected for some time,

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You can detect a note of abject disappointment in the voices of the reporters from all the news agencies that the dam hasn't burst. 

 

Nothing to see, pack up & go home. 

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22 hours ago, Robin-H said:

Why are they dropping bags of ballast then? 

You tell me!

 

The official reason is to prevent further erosion of the top soil if water comes over the wave wall, but given that the level is now so low (less than 48% of capacity) that it would take months of heavy rain to even reach that level again, it is completely pointless. It actually makes it harder to effect a ‘proper’ repair and puts further strain on the concrete slabs below which seem to have been ‘loosened’ by vegetation being allowed to grow in the gaps between the slabs. Any repair will probably be to remove all the slabs which form the slipway and replace it with a single concrete skin. You can even mix fungicides with concrete these days to prevent anything growing on it.

 

As I said earlier, I get the impression that the initial response was led by the emergency services and local officials and not by structural engineers. All that was needed was to evacuate the town and start pumping the water into the river below. There is very little danger of the dam itself collapsing.

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14 minutes ago, Top Cats Hat said:

You tell me!

 

The official reason is to prevent further erosion of the top soil if water comes over the wave wall, but given that the level is now so low (less than 48% of capacity) that it would take months of heavy rain to even reach that level again, it is completely pointless. It actually makes it harder to effect a ‘proper’ repair and puts further strain on the concrete slabs below which seem to have been ‘loosened’ by vegetation being allowed to grow in the gaps between the slabs. Any repair will probably be to remove all the slabs which form the slipway and replace it with a single concrete skin. You can even mix fungicides with concrete these days to prevent anything growing on it.

 

As I said earlier, I get the impression that the initial response was led by the emergency services and local officials and not by structural engineers. All that was needed was to evacuate the town and start pumping the water into the river below. There is very little danger of the dam itself collapsing.

How do you know? Have you additional information than that presented in the media?

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10 minutes ago, makapaka said:

How do you know? Have you additional information than that presented in the media?

No.

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24 minutes ago, Top Cats Hat said:

You tell me!

 

The official reason is to prevent further erosion of the top soil if water comes over the wave wall, but given that the level is now so low (less than 48% of capacity) that it would take months of heavy rain to even reach that level again, it is completely pointless. It actually makes it harder to effect a ‘proper’ repair and puts further strain on the concrete slabs below which seem to have been ‘loosened’ by vegetation being allowed to grow in the gaps between the slabs. Any repair will probably be to remove all the slabs which form the slipway and replace it with a single concrete skin. You can even mix fungicides with concrete these days to prevent anything growing on it.

 

As I said earlier, I get the impression that the initial response was led by the emergency services and local officials and not by structural engineers. All that was needed was to evacuate the town and start pumping the water into the river below. There is very little danger of the dam itself collapsing.

Presumably that would stop those pesky mushrooms, but not much else!

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2 minutes ago, Top Cats Hat said:

No.

Dr Heidarzadeh, head of Coastal Engineering and Resilience at the Department of Civil and Environmental Engineering at Brunel University seems to disagree with you. 

 

"Whaley Bridge dam is an embankment dam which is equipped with a concrete spillway. Spillways are extremely important because they prevent embankment dams from overtopping. Overtopping of embankment dams is very dangerous because it can cause the dam to be washed away in a few hours and consequently trigger a big flood. Embankment dams are made from soil and so can be washed away rapidly. Due to heavy rainfall in the Whaley Bridge area, the spillway is now broken and a big chunk of its concrete structure is damaged.  There is a possibility that the spillway could then become fully broken in a few hours. If the spillway is fully gone, the embankment dam will be washed away very rapidly which could cause a massive flood". 

 

 

 

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5 minutes ago, Robin-H said:

Dr Heidarzadeh, head of Coastal Engineering and Resilience at the Department of Civil and Environmental Engineering at Brunel University seems to disagree with you. 

I do like the way you quote his full title and University as though that gives it added credence. It is simply just another opinion which in fact doesn’t disagree with anything I have said.

 

“There is a possibility that the spillway could then become fully broken”

 

The spillway was damaged by the volume of water flowing over it last week. It didn’t spontaneously collapse and it won’t now, given that the water level is no longer anywhere near the top of the dam. The biggest danger now to the damaged slipway is the hundreds of tons of added weight loaded onto the weakest section of it. 

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3 minutes ago, Top Cats Hat said:

I do like the way you quote his full title and University as though that gives it added credence. It is simply just another opinion which in fact doesn’t disagree with anything I have said.

 

“There is a possibility that the spillway could then become fully broken”

 

The spillway was damaged by the volume of water flowing over it last week. It didn’t spontaneously collapse and it won’t now, given that the water level is no longer anywhere near the top of the dam. The biggest danger now to the damaged slipway is the hundreds of tons of added weight loaded onto the weakest section of it. 

Of course it gives him credence. He is the head of an Engineering department at a good university. That gives him credence, and I would put more weight on his opinion than yours. Not all opinions are equal.

 

It's very arrogant to think that the engineers that have been assisting with the operation are so stupid that they have been doing something not only unnecessary, but that may cause more damage.  

 

 

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11 minutes ago, Robin-H said:

It's very arrogant to think that the engineers that have been assisting with the operation are so stupid that they have been doing something not only unnecessary, but that may cause more damage.  

Not really. It happens more often than you think.

 

You have no idea what discussions went on during the early hours of this incident and who was involved in those discussions. There was certainly no more than a visual inspection of the damage at the time, so that discussion would have involved a great deal of ‘what if?s’ and ‘we don’t really know!s’. Also the engineers don’t make the decisions, they just advise and it’s up to the authorities to accept or reject that advice.

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