Hammersmith Flyover to reopen to light traffic - BBC News
http://www.bbc.co.uk/news/uk-england-london-16540112
Boris Johnson, mayor of London, has announced that the Hammersmith Flyover in west London, which has been closed for three weeks, will reopen on Friday. It was shut when serious damage to cables in the structure was discovered. Transport for London (TfL) has said one lane will be open in each direction but it will be closed to HGVs and coaches. Closure of the A4 route, which is usually used by about 90,000 vehicles a day, has caused serious congestion in west London. 'Reduce disruption' A steady seepage of salt water into the structure, built in the 1960s, has weakened the structure, but engineers said it was now safe to take light traffic. TfL said the route would reopen "before the rush hour" on Friday but did not specify exactly when. Strengthening work will continue for the next four months and drivers are still advised to "consider avoiding the area if possible". Once new cables are installed, the flyover will be reopened to all traffic "well ahead of the London 2012 Games", said TfL. Garrett Emmerson, chief operating officer for surface transport, said: "This should significantly reduce the traffic disruption many thousands of drivers have been experiencing since the flyover closed." http://www.bbc.co.uk/news/uk-england-london-16540112 |
Hammersmith Flyover to reopen to light traffic - BBC News
Bruce wrote:
A steady seepage of salt water into the structure, built in the 1960s, has weakened the structure, but engineers said it was now safe to take light traffic. The flyover was equipped with electric heating elements under the road surface. These were specified in order to eliminate damage to the pre-stressed concrete structure from de-icing salt. Apparently the heating elements never worked properly from the outset. In that case, the best alternative would have been to use urea for de-icing, as is routine practice in Germany and some other countries. But no, the cheaper but potentially very damaging rock salt was used, and this is what has caused the problems with the pre-stressing cables within the concrete structure. |
Hammersmith Flyover to reopen to light traffic - BBC News
"Bruce" wrote in message
... Bruce wrote: A steady seepage of salt water into the structure, built in the 1960s, has weakened the structure, but engineers said it was now safe to take light traffic. But no, the cheaper but potentially very damaging rock salt was used, and this is what has caused the problems with the pre-stressing cables within the concrete structure. Presumably this isn't the only structure of this type on the road network though? Are many more due to be found before long? Paul S |
Hammersmith Flyover to reopen to light traffic - BBC News
"Paul Scott" wrote in message
... "Bruce" wrote in message ... Bruce wrote: A steady seepage of salt water into the structure, built in the 1960s, has weakened the structure, but engineers said it was now safe to take light traffic. But no, the cheaper but potentially very damaging rock salt was used, and this is what has caused the problems with the pre-stressing cables within the concrete structure. Presumably this isn't the only structure of this type on the road network though? Are many more due to be found before long? Found to have damage, I meant of course. Not just 'found'! Paul S |
Hammersmith Flyover to reopen to light traffic - BBC News
In message , at 12:41:12 on
Fri, 13 Jan 2012, Paul Scott remarked: A steady seepage of salt water into the structure, built in the 1960s, has weakened the structure, but engineers said it was now safe to take light traffic. But no, the cheaper but potentially very damaging rock salt was used, and this is what has caused the problems with the pre-stressing cables within the concrete structure. Presumably this isn't the only structure of this type on the road network though? Are many more due to be found before long? There were extensive repairs to the M6 viaduct in the Castle Bromwich area a couple of years ago, and the A14 flyover across Huntingdon station is widely regarded as being about to fall down. One of the bridges at the M6/M1 junction was replaced very recently. http://www.bbc.co.uk/news/uk-england-16460505 Not sure how many of these are salt related. -- Roland Perry |
Hammersmith Flyover to reopen to light traffic - BBC News
|
Hammersmith Flyover to reopen to light traffic - BBC News
"Paul Scott" wrote:
"Bruce" wrote in message .. . Bruce wrote: A steady seepage of salt water into the structure, built in the 1960s, has weakened the structure, but engineers said it was now safe to take light traffic. But no, the cheaper but potentially very damaging rock salt was used, and this is what has caused the problems with the pre-stressing cables within the concrete structure. Presumably this isn't the only structure of this type on the road network though? Are many more due to be found before long? There are plenty of structures of this type (precast segmental pre-stressed post-tensioned) but I think the Hammersmith flyover was the first. I don't know of any subsequent structure of this type that lacks the essential combination of bridge deck waterproofing, proper drainage, adequate concrete cover to reinforcement/pre-stressing tendons and grouting of tendon ducts. So Hammersmith is very much a one-off. That doesn't mean that other structures don't have problems of their own, but the design and subsequent operation and maintenance practice related to the Hammersmith flyover seems to have combined in a way that could only end in tears. |
Hammersmith Flyover to reopen to light traffic - BBC News
"Bruce" wrote in message
... There are plenty of structures of this type (precast segmental pre-stressed post-tensioned) but I think the Hammersmith flyover was the first. I don't know of any subsequent structure of this type that lacks the essential combination of bridge deck waterproofing, proper drainage, adequate concrete cover to reinforcement/pre-stressing tendons and grouting of tendon ducts. So Hammersmith is very much a one-off. That doesn't mean that other structures don't have problems of their own, but the design and subsequent operation and maintenance practice related to the Hammersmith flyover seems to have combined in a way that could only end in tears. I bet the DfT (or the Highways Agency) are glad that they they ceded all the trunk roads within London to the GLA. I'm thinking it must have been transferred at about the same time that all those random motorways within London were downgraded? Paul S |
Hammersmith Flyover to reopen to light traffic - BBC News
"Paul Scott" wrote: "Bruce" wrote: There are plenty of structures of this type (precast segmental pre-stressed post-tensioned) but I think the Hammersmith flyover was the first. I don't know of any subsequent structure of this type that lacks the essential combination of bridge deck waterproofing, proper drainage, adequate concrete cover to reinforcement/pre-stressing tendons and grouting of tendon ducts. So Hammersmith is very much a one-off. That doesn't mean that other structures don't have problems of their own, but the design and subsequent operation and maintenance practice related to the Hammersmith flyover seems to have combined in a way that could only end in tears. I bet the DfT (or the Highways Agency) are glad that they they ceded all the trunk roads within London to the GLA. I'm thinking it must have been transferred at about the same time that all those random motorways within London were downgraded? Yes, when the GLA (and hence TfL) was established in 2000. It formed part of what was initially called the GLRN (Greater London Road Network), subsequently renamed the TLRN (Transport for London Road Network). I doubt it, but it could conceivably have been a responsibility of H&F council pre-2000, rather than that of the HA. I think it fell under the auspices of the GLC in years past. Be interesting to know when the quasi-literal rot started! Re the downgraded motorways - I've read elsewhere speculation, which seems to have turned into received wisdom amongst some, that this only happened because of an oversight with the legislation establishing the powers of the GLA. I have my doubts about that theory - rather, I can well imagine it being intentional (the thinking being that the notion of widespread 'urban motorways' is rather something of the past) - but that's just speculation on my part. |
Hammersmith Flyover to reopen to light traffic - BBC News
"Mizter T" wrote:
"Paul Scott" wrote: "Bruce" wrote: There are plenty of structures of this type (precast segmental pre-stressed post-tensioned) but I think the Hammersmith flyover was the first. I don't know of any subsequent structure of this type that lacks the essential combination of bridge deck waterproofing, proper drainage, adequate concrete cover to reinforcement/pre-stressing tendons and grouting of tendon ducts. So Hammersmith is very much a one-off. That doesn't mean that other structures don't have problems of their own, but the design and subsequent operation and maintenance practice related to the Hammersmith flyover seems to have combined in a way that could only end in tears. I bet the DfT (or the Highways Agency) are glad that they they ceded all the trunk roads within London to the GLA. I'm thinking it must have been transferred at about the same time that all those random motorways within London were downgraded? Yes, when the GLA (and hence TfL) was established in 2000. It formed part of what was initially called the GLRN (Greater London Road Network), subsequently renamed the TLRN (Transport for London Road Network). I doubt it, but it could conceivably have been a responsibility of H&F council pre-2000, rather than that of the HA. I think it fell under the auspices of the GLC in years past. Be interesting to know when the quasi-literal rot started! The original client for the flyover was London County Council. Design was by G Maunsell and Partners and the flyover was constructed by Marples, Ridgeway and Partners Ltd.. http://www.engineering-timelines.com...em.asp?id=1164 |
Hammersmith Flyover to reopen to light traffic - BBC News
In message , Bruce
writes So Hammersmith is very much a one-off. That doesn't mean that other structures don't have problems of their own, but the design and subsequent operation and maintenance practice related to the Hammersmith flyover seems to have combined in a way that could only end in tears. No matter. There's little doubt that the prospect of all those Olympic athletes and officials setting out in their limousines from Heathrow, only to encounter the traffic jams that those of us who live in the area currently suffer, will ensure that it is all fixed in record time. -- Paul Terry |
Hammersmith Flyover to reopen to light traffic - BBC News
Paul Terry wrote:
In message , Bruce writes So Hammersmith is very much a one-off. That doesn't mean that other structures don't have problems of their own, but the design and subsequent operation and maintenance practice related to the Hammersmith flyover seems to have combined in a way that could only end in tears. No matter. There's little doubt that the prospect of all those Olympic athletes and officials setting out in their limousines from Heathrow, only to encounter the traffic jams that those of us who live in the area currently suffer, will ensure that it is all fixed in record time. If it is for the Olympics, it will be Money No Object. |
Hammersmith Flyover to reopen to light traffic - BBC News
In message , at 12:36:40
on Fri, 13 Jan 2012, remarked: There were extensive repairs to the M6 viaduct in the Castle Bromwich area a couple of years ago, and the A14 flyover across Huntingdon station is widely regarded as being about to fall down. One of the bridges at the M6/M1 junction was replaced very recently. http://www.bbc.co.uk/news/uk-england-16460505 Not sure how many of these are salt related. Huntingdon viaduct already relies on extensive supplementary steelwork to support it. But why does it *need* the support? Is the underlying issue one of salt corrosion. -- Roland Perry |
Hammersmith Flyover to reopen to light traffic - BBC News
On Fri, 13 Jan 2012 13:09:44 +0000, Roland Perry
wrote: There were extensive repairs to the M6 viaduct in the Castle Bromwich area a couple of years ago, and the A14 flyover across Huntingdon station is widely regarded as being about to fall down. One of the bridges at the M6/M1 junction was replaced very recently. I recall the Sunday Times getting excited about the M6 viaducts being at risk of collapse in Birmingham, must have been in the 1970s or '80s. The recent works are the second time they have had a thorough going over that I am aware of. The M6 bridge over the M1 was propped about 10 years ago. I don't know what weakened it: poor design, over-use or salt, could have been any of them. |
Hammersmith Flyover to reopen to light traffic - BBC News
Peter Johnson wrote:
On Fri, 13 Jan 2012 13:09:44 +0000, Roland Perry wrote: There were extensive repairs to the M6 viaduct in the Castle Bromwich area a couple of years ago, and the A14 flyover across Huntingdon station is widely regarded as being about to fall down. One of the bridges at the M6/M1 junction was replaced very recently. I recall the Sunday Times getting excited about the M6 viaducts being at risk of collapse in Birmingham, must have been in the 1970s or '80s. 80s. The problem was that the client deleted the sliding bearings that were needed to allow for movement, including thermal expansion and contraction, and replaced them with grease. Literally. Within months, the grease dried out and the beams seized on to their supports. So movement was no longer possible and temperature changes put massive stresses into the structure. The M6 bridge over the M1 was propped about 10 years ago. I don't know what weakened it: poor design, over-use or salt, could have been any of them. As with many highway structures, the vast increase in the allowable gross weight of the biggest lorries has created no end of problems. The damage done to the road itself is proportional to the fourth power of the axle weight of the vehicle. There must be a comparable relationship between gross vehicle weight and the effect on structures. |
Hammersmith Flyover to reopen to light traffic - BBC News
In article , (Roland Perry)
wrote: In message , at 12:36:40 on Fri, 13 Jan 2012, remarked: Huntingdon viaduct already relies on extensive supplementary steelwork to support it. But why does it *need* the support? Is the underlying issue one of salt corrosion. I don't think so. I think it's to do with the quality of the original concrete construction. -- Colin Rosenstiel |
Hammersmith Flyover to reopen to light traffic - BBC News
On Sat, 14 Jan 2012 15:34:09 -0600,
wrote: In article , (Roland Perry) wrote: In message , at 12:36:40 on Fri, 13 Jan 2012, remarked: Huntingdon viaduct already relies on extensive supplementary steelwork to support it. But why does it *need* the support? Is the underlying issue one of salt corrosion. I don't think so. I think it's to do with the quality of the original concrete construction. I don't think that it's just the concrete, it's a broader design concept than that; http://londonist.com/2012/01/will-so...th-flyover.php E&OE etc. JonH |
Hammersmith Flyover to reopen to light traffic - BBC News
In article ,
() wrote: On Sat, 14 Jan 2012 15:34:09 -0600, wrote: In article , (Roland Perry) wrote: In message , at 12:36:40 on Fri, 13 Jan 2012, remarked: Huntingdon viaduct already relies on extensive supplementary steelwork to support it. But why does it *need* the support? Is the underlying issue one of salt corrosion. I don't think so. I think it's to do with the quality of the original concrete construction. I don't think that it's just the concrete, it's a broader design concept than that; http://londonist.com/2012/01/will-so...wrong-with-the -hammersmith-flyover.php E&OE etc. Thanks for the link to an interesting article (with a few errors picked up in the comments) but I was referring to quite a different structure on the A14. -- Colin Rosenstiel |
Hammersmith Flyover to reopen to light traffic - BBC News
wrote:
On Sat, 14 Jan 2012 15:34:09 -0600, wrote: In article , (Roland Perry) wrote: In message , at 12:36:40 on Fri, 13 Jan 2012, remarked: Huntingdon viaduct already relies on extensive supplementary steelwork to support it. But why does it *need* the support? Is the underlying issue one of salt corrosion. I don't think so. I think it's to do with the quality of the original concrete construction. I don't think that it's just the concrete, it's a broader design concept than that; http://londonist.com/2012/01/will-so...th-flyover.php E&OE etc. Errors and Omissions Excepted?? There are plenty of potential errors in that article, but no omissions. Rarely have I seen someone make such a complex explanation of a very simple problem. Probably due to his lack of knowledge of this particular structure, the author seems to have wanted to cover all the possible problems in all possible concrete bridge structures. Perhaps he did omit two possibilities - cosmic rays and UFO impact. And then there's terrorist attack, so let's make that three. ;-) |
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