Suvarnabhumi Airport Runway Crisis Deepens

[ginjag]

Philw, you said the problem was small and is now fixed, this was a statement sent out to anyone silly enough to believe, PLEASE you read the report on the closures in the last year, it was posted, so you believe that was not true--or you dissmissed that at small probs ???? If a friend of yours happened to be on a flight and had a terrible experience with the plane landing and huge losses resulting, all because you and a few airport VIPs refused to believe in the airport HAS mega runway problems and will have for years.

[noahvail]

I'ts PATHETIC that 2 or 3 of you are still in denial, and cannot get your heads around the truth of this said airport was built with substandard materials, substandard companies, and a substandard greedy P.M. and family/friends of pocketing the vast rakeoffs. One poster had the gall to say that blaming Thaksin was wrong. YOU ARE PATHETIC.

+1

It's hard to believe that some people cannot believe that the raft of "small" problems is simply symptomatic of the much larger problems that lie beneath, and the causes of those problems. And, that they believe the spins that the AOT spokespeople put on those "small" problems.

[Steely Dan]

Why is everyone getting so worked up carrying out 'post-mortems', after all nobody has died, yet. Until we have an accident so large that the news can't be buried a sticking plaster will surely suffice.

[ginjag]

Steelydan, YET.... would be the word. to use, and you have a smash hit idea, sticking plasters, order a cartload and give them to AOT as a gift to keep reairing every day small cave ins.

[SOEYCHANLOY]

It seems Thais wait until things break, like airport runways with sink holes, instead of testing and doing preventative maintenance. Here is how to test runways, take preventative action, before aircraft are damaged. Could someone forward this to AOT?

Ha! Ha! Ha! My friend, nobody gives a shit at TOT. If an airplane crashes in "Soupharnabumy" they will simply say : it was the "falang" airplane no good!

Sent from my GT-S5830T using Thaivisa Connect App

[bigbamboo]

... a degreed civil engineer here... structural ... don't know it all, but do know a good bit about the subject.

... without inspecting the damages, we can only speculate on causes of the Suvarnabhumi runway failures ... but, this does not sound favorable for the AOT and Thailand's reputation as a nation capable of achieving international standards.

... a few observations ... basics:

• Concrete does not flex well... it is designed to sustain tremendous compression loads, so dropping a fully loaded A380 at 200 knots onto its surface is no problem for properly designed and constructed concrete runways; however,
  
• When subject to significant flexural (bending) loads, concrete fractures ... rather easily, actually ... concrete failure is not a slow, plastic bending, but a sharp dramatic failure ... the steel reinforcing bars embedded in the concrete is placed there to sustain the bending loads, called 'moment loads', that concrete cannot resist.
  

... what is described in the article above is a 60cm x 60cm section subsiding 5cm ... it sounds as a "punching" failure ... this is not the slow subsiding we are witnessing throughout Thailand ... the article does not describe a smooth flexing, which concrete cannot do, as with pliant materials (wood, metal, plastic, etc.) ... the article describes a concrete slab that cracked, separated and dropped 5cm below the level of the surfaces around it ... nothing about this form of concrete "punching" failure (if that is what this is) is normal ... it is not maintenance related ... it would be a dramatic structural failure.

... but a runway failure of this type should not be misconstrued as the problem ... it is not ... the runway failure as this is a symptom of a much greater problem ... the symptom could be caused by a couple of most likely sources:

• The higher probability is that inferior foundations are the most likely symptom of the problem ... no matter how competently the runway slab is designed and built, it is predicated on having a firm foundation ... a failed foundation almost invariably results in failed structures that sit upon them ... because the compacted substrate, subsoil drainage system and pilings (which I presume they used in a swamp) cannot be 100% tested (only sampled), there is a huge exposure here;
  
• Less likely is an inferior runway slab itself ... slab design is fairly straight-forward ... very well-developed, proved construction technology, materials and design standards ... the key is the foundation.
  

... the greater problem of a runway failure as this, as opposed to the symptoms of the problem, could in my view include the following, in order of likelihood:

• Most likely, is inferior quality construction practices ... not installing materials in conformance to the design... this could be simple gross mismanagement, which I've heard is not so unheard of here in Thailand ('mai pen rai' ... 'do just enough'... 'aww, you tink too mutt') ... or, if a Thai contractor did have larceny in him, relatively few co-conspiritors would have to be recruited to get away with taking inferior short cuts ... this is particularly possible when a great deal of work is done in the cool of the night, as was I believe the case here;
  
• A bit less likely, is inferior construction materials ... low-strength concrete, or low-strength reinforcing steel ... in an environment of corruption and incompetence, substituting inferior construction materials is a distinct possibility ... however, the safety factors applied in the design of structures (to international design standards) are quite forgiving ... if inferior materials were substituted, they would be substituted to massive degrees to cause a failure as this;
  
• Least likely, is inferior design ... engineers in Thailand are personally liable (civilly and criminally) for damages and deaths caused by the failures of structures they design ... to protect themselves, Thai engineers are understandably notorious for overdesigning structures to account for the corrupt building practices indemic in Thailand ... and, as mentioned above, international design standards include significant factors of safety that will forgive a measure of inferior construction practices and materials.
  

... but, going back to the top, if this runway failure is as described in the article (a 'punching' failure), this failure could well be the harbinger of a chronic decay of the runway, now underway ... unlikely that it is an isolated failure, but representative of how the entire runway was constructed.

... open 6 years now, major deficiencies at Suvarnabhumi Airport continue to mount ... these are not the isolated sort of corrections expected at the opening of new projects ... these are deeply flawed, fundamental systems deficiencies reflective of a broader mentality ... that is a concern.

... the Thai government is trying to remedially correct them, which is always inferior to doing them correctly in the first place ... leaky roof ... insufficient air-conditioning ... fire safety violations ... too few bathrooms ... radar and air traffic control system failures ... back-up power system failures ... spalling runway concrete ... insufficiently drained, highly expansive subsoils ... under-designed passenger capacity ... forget the ongoing operational problems, this is just the hardware.

... the world's latest technology, most experienced consultants and best contractors and suppliers were available to Thailand in launching it's greatest public infrastructure achievement to date ... Thailand's front door and calling card to the world is suffering signs of obsolesence ... it is 5-1/2 years old.

... anything anyone needs to know about this nation, doing business or living here, is neatly packaged in the story of the building of Thailand's Suvarnabhumi International Airport ... a remarkable story, truly.

Good info.

I'm not a structural engineer but even I'd be wary of building anything on top of a swamp....especially an airport.... and especially in Thailand.

Edited July 8, 2012 by bigbamboo

[Moruya]

So much rubbish posted in response to this story. The problem of cracking and stripping (where the bitumen comes away from the concrete below) is common. The issue here is the maintenance schedule. The sky is not falling. It is not the end of the world. Once the maintenance schedule is sorted everything will be fine. It is normal to have runways closed for resurfacing and repair work. I believe Sydney airport had a runway closed for nearly a year with maintenance and repair works taking place.

My understanding from posts from the other paper that they have found an area 60cm square sunk 5 cm.

I mean if that's true this story's a joke.

If the Thais are worried, so should we be.

An area 60cm squared is exactly twice the size of my lenovo laptop................................

How big is a runway in cm2 ???

And it's Thaksins, Yinglucks, the Governments fault..................

Pathetic.

My short post prompted all that bilge?

Marvelous!

[Moruya]

... a degreed civil engineer here... structural ... don't know it all, but do know a good bit about the subject.

... without inspecting the damages, we can only speculate on causes of the Suvarnabhumi runway failures ... but, this does not sound favorable for the AOT and Thailand's reputation as a nation capable of achieving international standards.

... a few observations ... basics:

• Concrete does not flex well... it is designed to sustain tremendous compression loads, so dropping a fully loaded A380 at 200 knots onto its surface is no problem for properly designed and constructed concrete runways; however,
  
• When subject to significant flexural (bending) loads, concrete fractures ... rather easily, actually ... concrete failure is not a slow, plastic bending, but a sharp dramatic failure ... the steel reinforcing bars embedded in the concrete is placed there to sustain the bending loads, called 'moment loads', that concrete cannot resist.
  

... what is described in the article above is a 60cm x 60cm section subsiding 5cm ... it sounds as a "punching" failure ... this is not the slow subsiding we are witnessing throughout Thailand ... the article does not describe a smooth flexing, which concrete cannot do, as with pliant materials (wood, metal, plastic, etc.) ... the article describes a concrete slab that cracked, separated and dropped 5cm below the level of the surfaces around it ... nothing about this form of concrete "punching" failure (if that is what this is) is normal ... it is not maintenance related ... it would be a dramatic structural failure.

... but a runway failure of this type should not be misconstrued as the problem ... it is not ... the runway failure as this is a symptom of a much greater problem ... the symptom could be caused by a couple of most likely sources:

• The higher probability is that inferior foundations are the most likely symptom of the problem ... no matter how competently the runway slab is designed and built, it is predicated on having a firm foundation ... a failed foundation almost invariably results in failed structures that sit upon them ... because the compacted substrate, subsoil drainage system and pilings (which I presume they used in a swamp) cannot be 100% tested (only sampled), there is a huge exposure here;
  
• Less likely is an inferior runway slab itself ... slab design is fairly straight-forward ... very well-developed, proved construction technology, materials and design standards ... the key is the foundation.
  

... the greater problem of a runway failure as this, as opposed to the symptoms of the problem, could in my view include the following, in order of likelihood:

• Most likely, is inferior quality construction practices ... not installing materials in conformance to the design... this could be simple gross mismanagement, which I've heard is not so unheard of here in Thailand ('mai pen rai' ... 'do just enough'... 'aww, you tink too mutt') ... or, if a Thai contractor did have larceny in him, relatively few co-conspiritors would have to be recruited to get away with taking inferior short cuts ... this is particularly possible when a great deal of work is done in the cool of the night, as was I believe the case here;
  
• A bit less likely, is inferior construction materials ... low-strength concrete, or low-strength reinforcing steel ... in an environment of corruption and incompetence, substituting inferior construction materials is a distinct possibility ... however, the safety factors applied in the design of structures (to international design standards) are quite forgiving ... if inferior materials were substituted, they would be substituted to massive degrees to cause a failure as this;
  
• Least likely, is inferior design ... engineers in Thailand are personally liable (civilly and criminally) for damages and deaths caused by the failures of structures they design ... to protect themselves, Thai engineers are understandably notorious for overdesigning structures to account for the corrupt building practices indemic in Thailand ... and, as mentioned above, international design standards include significant factors of safety that will forgive a measure of inferior construction practices and materials.
  

... but, going back to the top, if this runway failure is as described in the article (a 'punching' failure), this failure could well be the harbinger of a chronic decay of the runway, now underway ... unlikely that it is an isolated failure, but representative of how the entire runway was constructed.

... open 6 years now, major deficiencies at Suvarnabhumi Airport continue to mount ... these are not the isolated sort of corrections expected at the opening of new projects ... these are deeply flawed, fundamental systems deficiencies reflective of a broader mentality ... that is a concern.

... the Thai government is trying to remedially correct them, which is always inferior to doing them correctly in the first place ... leaky roof ... insufficient air-conditioning ... fire safety violations ... too few bathrooms ... radar and air traffic control system failures ... back-up power system failures ... spalling runway concrete ... insufficiently drained, highly expansive subsoils ... under-designed passenger capacity ... forget the ongoing operational problems, this is just the hardware.

... the world's latest technology, most experienced consultants and best contractors and suppliers were available to Thailand in launching it's greatest public infrastructure achievement to date ... Thailand's front door and calling card to the world is suffering signs of obsolesence ... it is 5-1/2 years old.

... anything anyone needs to know about this nation, doing business or living here, is neatly packaged in the story of the building of Thailand's Suvarnabhumi International Airport ... a remarkable story, truly.

Good info.

I'm not a structural engineer but even I'd be wary of building anything on top of a swamp....especially an airport.... and especially in Thailand.

I concur.

I wonder if the number of times it has been closed for repairs is normal

[ginjag]

Bigbamboo, Agree, but they built Bkk on top of a swamp, so the saying here is true, Thai are reluctant to change what they did before. If uncle said to boy you use a nail when fixing something into concrete then you do. When you borrow something you not normally return it, unless it's asked for back( usually it's not there anymore) if you get my drift. Thailand was doing pretty well, years ago, this friendly LOS. problem now is greed, (airport problems)

[swillowbee]

... a degreed civil engineer here... structural ... don't know it all, but do know a good bit about the subject.

... without inspecting the damages, we can only speculate on causes of the Suvarnabhumi runway failures ... but, this does not sound favorable for the AOT and Thailand's reputation as a nation capable of achieving international standards.

... a few observations ... basics:

• Concrete does not flex well... it is designed to sustain tremendous compression loads, so dropping a fully loaded A380 at 200 knots onto its surface is no problem for properly designed and constructed concrete runways; however,
  
• When subject to significant flexural (bending) loads, concrete fractures ... rather easily, actually ... concrete failure is not a slow, plastic bending, but a sharp dramatic failure ... the steel reinforcing bars embedded in the concrete is placed there to sustain the bending loads, called 'moment loads', that concrete cannot resist.
  

... what is described in the article above is a 60cm x 60cm section subsiding 5cm ... it sounds as a "punching" failure ... this is not the slow subsiding we are witnessing throughout Thailand ... the article does not describe a smooth flexing, which concrete cannot do, as with pliant materials (wood, metal, plastic, etc.) ... the article describes a concrete slab that cracked, separated and dropped 5cm below the level of the surfaces around it ... nothing about this form of concrete "punching" failure (if that is what this is) is normal ... it is not maintenance related ... it would be a dramatic structural failure.

... but a runway failure of this type should not be misconstrued as the problem ... it is not ... the runway failure as this is a symptom of a much greater problem ... the symptom could be caused by a couple of most likely sources:

• The higher probability is that inferior foundations are the most likely symptom of the problem ... no matter how competently the runway slab is designed and built, it is predicated on having a firm foundation ... a failed foundation almost invariably results in failed structures that sit upon them ... because the compacted substrate, subsoil drainage system and pilings (which I presume they used in a swamp) cannot be 100% tested (only sampled), there is a huge exposure here;
  
• Less likely is an inferior runway slab itself ... slab design is fairly straight-forward ... very well-developed, proved construction technology, materials and design standards ... the key is the foundation.
  

... the greater problem of a runway failure as this, as opposed to the symptoms of the problem, could in my view include the following, in order of likelihood:

• Most likely, is inferior quality construction practices ... not installing materials in conformance to the design... this could be simple gross mismanagement, which I've heard is not so unheard of here in Thailand ('mai pen rai' ... 'do just enough'... 'aww, you tink too mutt') ... or, if a Thai contractor did have larceny in him, relatively few co-conspiritors would have to be recruited to get away with taking inferior short cuts ... this is particularly possible when a great deal of work is done in the cool of the night, as was I believe the case here;
  
• A bit less likely, is inferior construction materials ... low-strength concrete, or low-strength reinforcing steel ... in an environment of corruption and incompetence, substituting inferior construction materials is a distinct possibility ... however, the safety factors applied in the design of structures (to international design standards) are quite forgiving ... if inferior materials were substituted, they would be substituted to massive degrees to cause a failure as this;
  
• Least likely, is inferior design ... engineers in Thailand are personally liable (civilly and criminally) for damages and deaths caused by the failures of structures they design ... to protect themselves, Thai engineers are understandably notorious for overdesigning structures to account for the corrupt building practices indemic in Thailand ... and, as mentioned above, international design standards include significant factors of safety that will forgive a measure of inferior construction practices and materials.
  

... but, going back to the top, if this runway failure is as described in the article (a 'punching' failure), this failure could well be the harbinger of a chronic decay of the runway, now underway ... unlikely that it is an isolated failure, but representative of how the entire runway was constructed.

... open 6 years now, major deficiencies at Suvarnabhumi Airport continue to mount ... these are not the isolated sort of corrections expected at the opening of new projects ... these are deeply flawed, fundamental systems deficiencies reflective of a broader mentality ... that is a concern.

... the Thai government is trying to remedially correct them, which is always inferior to doing them correctly in the first place ... leaky roof ... insufficient air-conditioning ... fire safety violations ... too few bathrooms ... radar and air traffic control system failures ... back-up power system failures ... spalling runway concrete ... insufficiently drained, highly expansive subsoils ... under-designed passenger capacity ... forget the ongoing operational problems, this is just the hardware.

... the world's latest technology, most experienced consultants and best contractors and suppliers were available to Thailand in launching it's greatest public infrastructure achievement to date ... Thailand's front door and calling card to the world is suffering signs of obsolesence ... it is 5-1/2 years old.

... anything anyone needs to know about this nation, doing business or living here, is neatly packaged in the story of the building of Thailand's Suvarnabhumi International Airport ... a remarkable story, truly.

As a degreed civil engineer, why have you not gone into detail about subsidence, the causes of it - re building on swamp land, the dispersion of water from the supporting sub-strates (sand and limestone in this case), the causes of air pockets and sub-support ground failure when the water which supports those substrates is dispersed, tapped, drained, and so on as the list goes on.

I was hoping for some asertions from a 'civil' engineer to some of my previous posts and statements, which I sourced from general knowledge, and even quoted an internet source.

Would you care to go into detail about the subsidence happening below the concrete slabs, as I think most don't have a problem with the runway surface construction.

-mel.

Mel

Lets be fair, the post by swillowbee is quite awesome and full of excellent information. If he types like me it probably took 25 mins and a cup of coffee. The additional info you want would be great but give the guy a chance, only so many hours in the day eh!

I like you understand that the geology is the issue, What swampy does not want is very wet rainy seasons followed by prolonged periods of heat and drought. The subsequent fall in the level of the water table and the accompanied 'shrinkage' are the conditions that could see gaping holes appear, but in the nature that swillowbee describes, sudden, violent and dramatic, and enough to ruin your day if you are in the stages of a take off run or landing.

To give you an idea of how dramatic and sudden these things occur when the wrong geology is in place, check out the mother below that opened in Guatemala after a tropical storm!!! Photoshop not involved!

It was exactly this kind of extreme scenario and those in Florida that I wan't referring to though mate.

It's the constant smaller troughs that develop all over the place, roads sinking in BKK and everywhere as a result of poor substructure laying, and a non-undertsanding of sedimentary requirements below, in the first place, that's the worry. For this to be now happening below runways..... well... I have no words really to explain the catostrophes awating, nor the ignorance of the authorities to just cover them up with blind blankets of what they believe is crack filling as the ultimate answer.

Oh! and Edit: No disrespect to you swillowbee, I was looking for further evidence of the ground subsidence and not surface failure, from a qualified person.... thaz all folks!

.

MEL1, you are of course correct -- no offense taken. Let me continue and try to relate how the geotechnical conditions below the Suvarnabhumi Airport have huge implications to its stability.

The engineer’s design for the runway itself is not so difficult – there are few unknowns, variables are all estimable and much advanced design technology exists.

The foundations upon which the runway is built is another animal altogether, especially when is located on a swamp, which are generally soggy, clay soils – a muddy muck. While building here can be done by competent engineers and contractors, the geology beneath Suvarnabhumi Airport is the least favorable upon which to build anything, except maybe a world-class swamp. But, the decision to build here was undounbtedly made by Thai politicians, whose knowledge of heady technical subjects are now notorious thoughout the modern world ... (sorry, I couldn't help that).

The underpinning geology and the criteria for designing a foundation is the domain of geotechnical engineers, specialist in assaying the structural capacity of the soils upon which structures are built. Before design commences, geotechnical engineers drill test borings throughout a construction site, from which they extract soil samples, evaluate the sampled soil characteristics in a laboratory and make recommendations to the structural engineers on the foundation design.

The foundations they recommend fall into two broad categories:

• Deep foundations – bored or driven piles sunk deep into the soil to a point that they can bear on solid rock, or have enough friction along their lengths that they can resist substantial downward and upward loads; and,
  
• Shallow foundations – foundations that might be at, or only a few meters below, the bottom of the building structure above, which spread the building loads over the soil beneath upon which they directly bear.
  

All of the area about BKK is an ancient alluvial plane, built-up from soils deposited over the millennia by the Chao Phraya River which has probably meandered all over this region for hundreds of kilometers in all directions. These soils are typically very poor and contain large amounts of clay, which is the worst soil on which to build. Clayey soils:

• Are incapable of supporting a lot of weight spread over their surface; and,
  
• Move around a lot, even seasonally, expanding and contracting depending upon their water content. Being that Thailand still floods frequently, a blinding warning light would have been shrieking at the engineers on this second point.
  

Add to that the regional subsidence that is occurring all about BKK, caused by pumping down the water table, and you have a challenging design.

Shallow foundation designs on expansive soils are expected to move – the hydrostatic pressures driving soil expansion and contraction is too great to reasonably resist. That movement can be designed for, so that elements of the foundation move as a single monolith. However, the differential movement of a single concrete foundation element is what causes failure – concrete doesn’t take well to bending , which is a consequence of trying to ‘float’ on top of an expanding and contracting bed of clayey soil that is moving all over the place, in different directions and rates.

So, my guess is that the foundation design for Suvarnabhumi runways are deep foundations – deep piles are the overwhelming choice for most any foundation in this region.

How regional subsidence plays into that, I do not exactly know. Frankly, I believe regional subsidence poses far less a threat to foundations than the structural character of the very dynamic local clayey soils beneath the Suvarnabhumi runway.

This part is important – an absolutely critical key to building on clayey soils is:

• Draining it to optimum water content;
  
• Once stabilized, maintaining that steady water content; and,
  
• Making certain that water does not migrate in and out, which causes it to expand and contract.
  

To achieve this, the proper design and construction of a high quality subsoil water drainage system is absolutely essential.

The design of a subsoil water drainage system is not so difficult – again, plenty of history and some great technology out there. But, the installation of the system itself is rife with exposure. It has to be right – there are no short-cuts, or material substitutions that won’t affect the final product – reducing the sizes of the drainage pipes, compromising the select gravel and sand mix in which they are enveloped, substituting a cheaper low-quality geo-textile filter fabric, not compacting the substrate adequately are all false savings a contractor can offer to reduce costs.

And, it is buried, so can easily conceal a legion of mistakes and compromises.

If it is not done correctly, the drain lines eventually build-up with silt, stop intercepting the water that wants to migrate in and out, and the clayey soils return to their natural state, expanding and contracting with enormous forces, driven by hydrostatic pressures that crack even a thick slab of reinforced runway concrete.

I am about all written-out here guys -- maybe a proper geotechnical engineer can chime in and properly characterize what I’ve attempted on the geotechnical aspect.

As for the forum members who say a chunk of runway “about twice the size of my laptop computer” is nothing about which to be concerned, I’ll do you better than that. A strip of rubber tire about the size of three rows off your laptop keyboard, sucked off the runway into an engine caused the Air France Concorde to auger in.

Maybe a chunk of concrete the size of your laptop’s CPU, chipped up by the nose landing gear into an engine on takeoff would do the same. Does that not worry you? ... even just ... a little?

Again, the failure of this small section is not the problem, but a symptom of what could be a far greater concern – a continuing decay of the entire runway system, until it is a patchwork of separate ‘floating’ chunks of concrete all bound together at the surface with epoxy grout.

If this is the “punching” failure described in the article, this might not be over.

Edited July 8, 2012 by swillowbee

[Rob8891]

Swillowbee, you deserve a medal, (and a long rest after all that typing)..... Thanks... it was highly informative, readble and not a single cheap-shot in it.

I'm flying into Swampy on Wednesday..... after reading your report, I have to admit in advance that any loose masonry on the runway will be entirely due to me,,,,.

[Reasonableman]

Very clear explanation for we laypersons. Thanks so much. RM

[KireB]

Flew in from Shanghai this afternoon and it was great, circling around the bay of Bangkok 3 times, seeing all those islands, Pattaya in the distance and all. Beat Google earth, just a shame that we, again, arrived 50 minutes too late. Immigration was flawless and took 2 minutes to be honest (avoid Immigration section 2 and go for 1 or 3!)

[hellodolly]

... a degreed civil engineer here... structural ... don't know it all, but do know a good bit about the subject.

... without inspecting the damages, we can only speculate on causes of the Suvarnabhumi runway failures ... but, this does not sound favorable for the AOT and Thailand's reputation as a nation capable of achieving international standards.

... a few observations ... basics:

• Concrete does not flex well... it is designed to sustain tremendous compression loads, so dropping a fully loaded A380 at 200 knots onto its surface is no problem for properly designed and constructed concrete runways; however,
  
• When subject to significant flexural (bending) loads, concrete fractures ... rather easily, actually ... concrete failure is not a slow, plastic bending, but a sharp dramatic failure ... the steel reinforcing bars embedded in the concrete is placed there to sustain the bending loads, called 'moment loads', that concrete cannot resist.
  

... what is described in the article above is a 60cm x 60cm section subsiding 5cm ... it sounds as a "punching" failure ... this is not the slow subsiding we are witnessing throughout Thailand ... the article does not describe a smooth flexing, which concrete cannot do, as with pliant materials (wood, metal, plastic, etc.) ... the article describes a concrete slab that cracked, separated and dropped 5cm below the level of the surfaces around it ... nothing about this form of concrete "punching" failure (if that is what this is) is normal ... it is not maintenance related ... it would be a dramatic structural failure.

... but a runway failure of this type should not be misconstrued as the problem ... it is not ... the runway failure as this is a symptom of a much greater problem ... the symptom could be caused by a couple of most likely sources:

• The higher probability is that inferior foundations are the most likely symptom of the problem ... no matter how competently the runway slab is designed and built, it is predicated on having a firm foundation ... a failed foundation almost invariably results in failed structures that sit upon them ... because the compacted substrate, subsoil drainage system and pilings (which I presume they used in a swamp) cannot be 100% tested (only sampled), there is a huge exposure here;
  
• Less likely is an inferior runway slab itself ... slab design is fairly straight-forward ... very well-developed, proved construction technology, materials and design standards ... the key is the foundation.
  

... the greater problem of a runway failure as this, as opposed to the symptoms of the problem, could in my view include the following, in order of likelihood:

• Most likely, is inferior quality construction practices ... not installing materials in conformance to the design... this could be simple gross mismanagement, which I've heard is not so unheard of here in Thailand ('mai pen rai' ... 'do just enough'... 'aww, you tink too mutt') ... or, if a Thai contractor did have larceny in him, relatively few co-conspiritors would have to be recruited to get away with taking inferior short cuts ... this is particularly possible when a great deal of work is done in the cool of the night, as was I believe the case here;
  
• A bit less likely, is inferior construction materials ... low-strength concrete, or low-strength reinforcing steel ... in an environment of corruption and incompetence, substituting inferior construction materials is a distinct possibility ... however, the safety factors applied in the design of structures (to international design standards) are quite forgiving ... if inferior materials were substituted, they would be substituted to massive degrees to cause a failure as this;
  
• Least likely, is inferior design ... engineers in Thailand are personally liable (civilly and criminally) for damages and deaths caused by the failures of structures they design ... to protect themselves, Thai engineers are understandably notorious for overdesigning structures to account for the corrupt building practices indemic in Thailand ... and, as mentioned above, international design standards include significant factors of safety that will forgive a measure of inferior construction practices and materials.
  

... but, going back to the top, if this runway failure is as described in the article (a 'punching' failure), this failure could well be the harbinger of a chronic decay of the runway, now underway ... unlikely that it is an isolated failure, but representative of how the entire runway was constructed.

... open 6 years now, major deficiencies at Suvarnabhumi Airport continue to mount ... these are not the isolated sort of corrections expected at the opening of new projects ... these are deeply flawed, fundamental systems deficiencies reflective of a broader mentality ... that is a concern.

... the Thai government is trying to remedially correct them, which is always inferior to doing them correctly in the first place ... leaky roof ... insufficient air-conditioning ... fire safety violations ... too few bathrooms ... radar and air traffic control system failures ... back-up power system failures ... spalling runway concrete ... insufficiently drained, highly expansive subsoils ... under-designed passenger capacity ... forget the ongoing operational problems, this is just the hardware.

... the world's latest technology, most experienced consultants and best contractors and suppliers were available to Thailand in launching it's greatest public infrastructure achievement to date ... Thailand's front door and calling card to the world is suffering signs of obsolesence ... it is 5-1/2 years old.

... anything anyone needs to know about this nation, doing business or living here, is neatly packaged in the story of the building of Thailand's Suvarnabhumi International Airport ... a remarkable story, truly.

Good info.

I'm not a structural engineer but even I'd be wary of building anything on top of a swamp....especially an airport.... and especially in Thailand.

Well I am not a engineer either. But I have a little knowledge of concrete.

I can not imagine how a section 60cm by 60cm in the middle of a huge slab could shrink enough to sink 5 cm. In English that is a 2 foot by 2 foot slab in the middle of a huge slab separating and sinking 2 inches.

For this to happen the concrete would first have to crack and then shrink enough so that the rough edges would allow it to sink 2 inches. For sure shoddy construction would be involved such as improper compaction of the base no rebar in the area and I am fairly sure the plan called for rebar closer together than 2 feet apart and inferior concrete.

Even with inferior concrete it would have shrunk as much as it was going to in one year. Just sounds fishy to me.

[animatic]

While that Guatemalan sink hole is extreme.

But having the weight and down force of a full sized jet liner, hit a weakened area of tarmac, is enough to make it drop instantly a foot or more if it is undermined, and that could send a plane instantly careening off course.... disaster of massive proportions if it heads towards another loaded plane waiting to take off.

This is not a simple no worries issue.

and McDonnlel Douglas MD 81 weights 72,575tons

Hard landing limits:

More than +2.0 g or sink rate in excess of 10 ft/s (600 ft/min)

If any of these values is exceeded a hard landing inspection must be performed.

For Boeing aircraft it's from 1.7-2.1 g's

A typical transport has a deceleration rate on landing of 0.7-1.5g.

...where the load factor

N = (Force on the Shock)/mass/gravity = acceleration/gravity = vertical acceleration rate in g's.

Add 1 for g-force.

The fact that aircraft landing gear is termed landing gear and not take-off gear implies that the most critical part of their design concerns landings.

Landing is the phase of flight that dishes out the greatest stresses to landing gear.

Seasoned air travelers may have experienced a particularly hard landing where they wondered how the wheels of the plane survived the jolt, while naval pilots routinely impose extreme loads on their gear when literally hitting the deck of aircraft carriers. Calculating the impulse force on the landing gear uses formulas from physics....

....Use the basic force formula F = ma to solve for total force of the 32,000 pound aircraft decelerating from 12 feet-per-second downward. Substituting, F pounds force = 32,000 pounds X 53.83 feet/sec^2/32.2 feet/sec^2 (acceleration of gravity) = 53,495.65 pounds force/ 2 main landing gear = 26,748 pounds to each gear strut for the 0.2223-seconds it takes to deflect the suspension 16 inches.

Read more:

How to Calculate Force Impulse on Landing Gear of Aircraft | eHow.com http://www.ehow.com/...l#ixzz202FsOi1G

Soooo, lets drop

26,748 pounds repeatedly

on your typical Thailand cement over land fill construction,

and see how long it holds up,

after being under mined by sub-terrain water flows.

Let's now assume a direct hit on a undermined weakened point.

This is not about shrinkage, but lateral forces applied repeatedly.

Edited July 8, 2012 by animatic

[PaullyW]

swillowbee,

I also wanted to thank you for taking what must have been a decent amount of time to offer your input. It's not often that TV members (myself included) actually make so much effort. A very big thank you. Now, if ONLY the Thai 'media' could get someone (anyone; Thai or non-Thai) to offer a similarly detailed opinion of what the heck is going on, we would be able to have an even better conversation. Sadly, my expectation is that we will only get these silly, unintelligent pieces that barely scratch the surface requiring us to speculate -- as always.

[ratcatcher]

While that Guatemalan sink hole is extreme.

But having the weight and down force of a full sized jet liner, hit a weakened area of tarmac, is enough to make it drop instantly a foot or more if it is undermined, and that could send a plane instantly careening off course.... disaster of massive proportions if it heads towards another loaded plane waiting to take off.

This is not a simple no worries issue.

and McDonnlel Douglas MD 81 weights 72,575tons

Hard landing limits:

More than +2.0 g or sink rate in excess of 10 ft/s (600 ft/min)

If any of these values is exceeded a hard landing inspection must be performed.

For Boeing aircraft it's from 1.7-2.1 g's

A typical transport has a deceleration rate on landing of 0.7-1.5g.

...where the load factor

N = (Force on the Shock)/mass/gravity = acceleration/gravity = vertical acceleration rate in g's.

Add 1 for g-force.

The fact that aircraft landing gear is termed landing gear and not take-off gear implies that the most critical part of their design concerns landings.

Landing is the phase of flight that dishes out the greatest stresses to landing gear.

Seasoned air travelers may have experienced a particularly hard landing where they wondered how the wheels of the plane survived the jolt, while naval pilots routinely impose extreme loads on their gear when literally hitting the deck of aircraft carriers. Calculating the impulse force on the landing gear uses formulas from physics....

....Use the basic force formula F = ma to solve for total force of the 32,000 pound aircraft decelerating from 12 feet-per-second downward. Substituting, F pounds force = 32,000 pounds X 53.83 feet/sec^2/32.2 feet/sec^2 (acceleration of gravity) = 53,495.65 pounds force/ 2 main landing gear = 26,748 pounds to each gear strut for the 0.2223-seconds it takes to deflect the suspension 16 inches.

Read more:

How to Calculate Force Impulse on Landing Gear of Aircraft | eHow.com http://www.ehow.com/...l#ixzz202FsOi1G

Soooo, lets drop

26,748 pounds repeatedly

on your typical Thailand cement over land fill construction,

and see how long it holds up,

after being under mined by sub-terrain water flows.

Let's now assume a direct hit on a undermined weakened point.

This is not about shrinkage, but lateral forces applied repeatedly.

Animatic, I hope you meant kilograms?

[metisdead]

A post has been removed for failure to use quote function leading to misunderstanding of who posted what.

[hellodolly]

A post has been removed for failure to use quote function leading to misunderstanding of who posted what.

That would be me.

What I was doing was thanking swillowbee for explaining that yes we did have the technology to build a airport there.

He in no way implied that they had used it. He just briefly explained how it could have been properly done.

I personally think to many corners cut and money pocketed to do the job properly.

I am also sure the plans were laid out to do the job properly.

The one thing I can not understand is how a 4squre foot piece in the middle of the slab with rebar in it could crack wide enough on four sides to allow it to sink 2 inches. If it had been on a corner it would easily be explained. It obviously had no rebar through that section.

[whybother]

I don't see that there should be any issues with building an airport on a swamp. I know of a few airports built on water.

Sent from my shoe phone

[jerrysteve]

Whats are the lives from a crash of a jetliner compared to the amound of tourist dollars anyway.

More news like this needs to be circulated in newspaperws around the world along with unsolved murders of foreigners and all categories of crime.

The more newspapers that are circulated around the world with negative news surrounding Thailand, the better. Perhaps it will cause them to finally get their act together.

Constantly hitting them hard in their pocket books is the only thing that just might get their attention.

[Mr Red]

At least swampy doesn't have this ...

http://content.usatoday.com/communities/ondeadline/post/2012/07/us-airways-plane-gets-stuck-in-tarmac-because-of-the-heat-/1

[animatic]

While that Guatemalan sink hole is extreme.

But having the weight and down force of a full sized jet liner, hit a weakened area of tarmac, is enough to make it drop instantly a foot or more if it is undermined, and that could send a plane instantly careening off course.... disaster of massive proportions if it heads towards another loaded plane waiting to take off.

This is not a simple no worries issue.

and McDonnlel Douglas MD 81 weights 72,575tons <<< lbs. not tons

Hard landing limits:

More than +2.0 g or sink rate in excess of 10 ft/s (600 ft/min)

If any of these values is exceeded a hard landing inspection must be performed.

For Boeing aircraft it's from 1.7-2.1 g's

A typical transport has a deceleration rate on landing of 0.7-1.5g.

...where the load factor

N = (Force on the Shock)/mass/gravity = acceleration/gravity = vertical acceleration rate in g's.

Add 1 for g-force.

The fact that aircraft landing gear is termed landing gear and not take-off gear implies that the most critical part of their design concerns landings.

Landing is the phase of flight that dishes out the greatest stresses to landing gear.

Seasoned air travelers may have experienced a particularly hard landing where they wondered how the wheels of the plane survived the jolt, while naval pilots routinely impose extreme loads on their gear when literally hitting the deck of aircraft carriers. Calculating the impulse force on the landing gear uses formulas from physics....

....Use the basic force formula F = ma to solve for total force of the 32,000 pound aircraft decelerating from 12 feet-per-second downward. Substituting, F pounds force = 32,000 pounds X 53.83 feet/sec^2/32.2 feet/sec^2 (acceleration of gravity) = 53,495.65 pounds force/ 2 main landing gear = 26,748 pounds to each gear strut for the 0.2223-seconds it takes to deflect the suspension 16 inches.

Read more:

How to Calculate Force Impulse on Landing Gear of Aircraft | eHow.com http://www.ehow.com/...l#ixzz202FsOi1G

Soooo, lets drop

26,748 pounds repeatedly

on your typical Thailand cement over land fill construction,

and see how long it holds up,

after being under mined by sub-terrain water flows.

Let's now assume a direct hit on a undermined weakened point.

This is not about shrinkage, but lateral forces applied repeatedly.

Animatic, I hope you meant kilograms?

LOL Thanks mate that would be 77,000 pounds

Weights

MD-81 - Operating empty 35,329kg (77,888lb),

max takeoff 63,505kg (140,000lb),

or 67,810kg (149,500lb) with JT8D-217As.

MD-88 - Operating empty 35,369kg (77,976lb),

max takeoff 67,810kg (149,500lb).

http://www.airliners...ats.main?id=109

In any case, the point being that significant stresses are placed on runway tarmacs

anytime an airliner lands, or just sitting still. If undermined by water, the cement is under-supported, no matter how much rebar in it, it will crack and eventually give way under the vibrational stress of other planes landing and sheer force of weight/gravity.

Edited July 9, 2012 by animatic

[Konini]

I want to thank everybody for the information in this thread. I have learned more about civil engineering in the last 3 days than in almost 50 years. Also huge kudos to those who are knowledgeable for putting things simplistically and in terms that the layman could easily understand. If I have read correctly, one thing concerns me; 15 minutes to repair. Back home it would take a full day for a 60x60 pothole to be fixed by the road crew, including the Stop/Slow man (2 day course - SERIOUSLY. A friend got a job at the council and had to go to South Melbourne for a 2 day course on operating the Stop/Slow lollipop. Honestly, I'm really not kidding. This happened).

Still unclear though if it would be a bumpy landing or a major disaster.

[Pseudolus]

From each drama, an opportunity. how long until we hear Hottie Yingluck proclaim

"Thailand to be Hub of Sink Hole research in 3 years; Airport moved to Don Muang as continued tourism growth exceeds all expectations" .

Edited July 9, 2012 by Pseudolus

[swillowbee]

.

I want to thank everybody for the information in this thread. I have learned more about civil engineering in the last 3 days than in almost 50 years. Also huge kudos to those who are knowledgeable for putting things simplistically and in terms that the layman could easily understand. If I have read correctly, one thing concerns me; 15 minutes to repair. Back home it would take a full day for a 60x60 pothole to be fixed by the road crew, including the Stop/Slow man (2 day course - SERIOUSLY. A friend got a job at the council and had to go to South Melbourne for a 2 day course on operating the Stop/Slow lollipop. Honestly, I'm really not kidding. This happened).

Still unclear though if it would be a bumpy landing or a major disaster.

.

... "a bumpy landing or a major disaster"?

... a runway slab failure is unlikely to be a dramatic collapse of the runway, creating a gaping hole as the sinkholes we view on YouTube ... it would more likely be an incremental cracking and separation of sections from the large monolithic slab that engineers designed... if subjected to a loaded aircraft hitting the runway at 150+ knots, the differential movement around the cracks would likely cause the concrete to break away, creating small chunks of loose concrete.

... on landing ... I imagine aircraft landing gear and tires are designed to take quite a shock load ... seems to me that a moderately rough landing is the worse it could cause, were the failures not spotted and temporarily patched ... (probably filling it with a high strength epoxy grout ... but, that does not repair the cause of the problem, which is likely beneath the runway slab).

... on takeoff ... it seems to me the greater risk is that the nose gear of an aircraft on takeoff chips one of these loose pieces of concrete off the pavement and into an engine intake ... modern aircraft jet engines are designed to work even after taking a whole frozen goose through the length of the engine and puking it out the exhaust looking as goose crap slammed through a strainer at Mach 2 ... however, I am uncertain how an engine at full takeoff thrust would pass a piece of concrete ... a bit harder than Canada goose beaks and eyeballs.

... you might have seen sailors, lined up shoulder to shoulder, policing an aircraft carrier deck before the start of air operations ... they are removing debris ... I am sure airports do the same thing, routinely ... I couldn't guess what is normal debris and what is abnormal debris (size, frequency, and character), and if the failure of a concrete runway as described above is as risky as it seems it could be.

... I don't know guys ... I think the story is not over ... with the horrendous Thai political fighting here, the truth about what they find out there will probably be deformed beyond all recognition.

Edited July 9, 2012 by swillowbee

[PaullyW]

From each drama, an opportunity. how long until we hear Hottie Yingluck proclaim

"Thailand to be Hub of Sink Hole research in 3 years; Airport moved to Don Muang as continued tourism growth exceeds all expectations" .

Well, she already made a statement proclaiming that the airport issues are nothing to worry about. What kind of country has a PM or similar make statements about its airports? I thought it was so strange.

[Moruya]

From each drama, an opportunity. how long until we hear Hottie Yingluck proclaim

"Thailand to be Hub of Sink Hole research in 3 years; Airport moved to Don Muang as continued tourism growth exceeds all expectations" .

Well, she already made a statement proclaiming that the airport issues are nothing to worry about. What kind of country has a PM or similar make statements about its airports? I thought it was so strange.

We all remember Chalerm telling us that there were no bombers in the country. Then the Keystone bombers came.

[Skywalker69]

... a degreed civil engineer here... structural ... don't know it all, but do know a good bit about the subject.

... without inspecting the damages, we can only speculate on causes of the Suvarnabhumi runway failures ... but, this does not sound favorable for the AOT and Thailand's reputation as a nation capable of achieving international standards.

... a few observations ... basics:

• Concrete does not flex well... it is designed to sustain tremendous compression loads, so dropping a fully loaded A380 at 200 knots onto its surface is no problem for properly designed and constructed concrete runways; however,
  
• When subject to significant flexural (bending) loads, concrete fractures ... rather easily, actually ... concrete failure is not a slow, plastic bending, but a sharp dramatic failure ... the steel reinforcing bars embedded in the concrete is placed there to sustain the bending loads, called 'moment loads', that concrete cannot resist.
  

... what is described in the article above is a 60cm x 60cm section subsiding 5cm ... it sounds as a "punching" failure ... this is not the slow subsiding we are witnessing throughout Thailand ... the article does not describe a smooth flexing, which concrete cannot do, as with pliant materials (wood, metal, plastic, etc.) ... the article describes a concrete slab that cracked, separated and dropped 5cm below the level of the surfaces around it ... nothing about this form of concrete "punching" failure (if that is what this is) is normal ... it is not maintenance related ... it would be a dramatic structural failure.

... but a runway failure of this type should not be misconstrued as the problem ... it is not ... the runway failure as this is a symptom of a much greater problem ... the symptom could be caused by a couple of most likely sources:

• The higher probability is that inferior foundations are the most likely symptom of the problem ... no matter how competently the runway slab is designed and built, it is predicated on having a firm foundation ... a failed foundation almost invariably results in failed structures that sit upon them ... because the compacted substrate, subsoil drainage system and pilings (which I presume they used in a swamp) cannot be 100% tested (only sampled), there is a huge exposure here;
  
• Less likely is an inferior runway slab itself ... slab design is fairly straight-forward ... very well-developed, proved construction technology, materials and design standards ... the key is the foundation.
  

... the greater problem of a runway failure as this, as opposed to the symptoms of the problem, could in my view include the following, in order of likelihood:

• Most likely, is inferior quality construction practices ... not installing materials in conformance to the design... this could be simple gross mismanagement, which I've heard is not so unheard of here in Thailand ('mai pen rai' ... 'do just enough'... 'aww, you tink too mutt') ... or, if a Thai contractor did have larceny in him, relatively few co-conspiritors would have to be recruited to get away with taking inferior short cuts ... this is particularly possible when a great deal of work is done in the cool of the night, as was I believe the case here;
  
• A bit less likely, is inferior construction materials ... low-strength concrete, or low-strength reinforcing steel ... in an environment of corruption and incompetence, substituting inferior construction materials is a distinct possibility ... however, the safety factors applied in the design of structures (to international design standards) are quite forgiving ... if inferior materials were substituted, they would be substituted to massive degrees to cause a failure as this;
  
• Least likely, is inferior design ... engineers in Thailand are personally liable (civilly and criminally) for damages and deaths caused by the failures of structures they design ... to protect themselves, Thai engineers are understandably notorious for overdesigning structures to account for the corrupt building practices indemic in Thailand ... and, as mentioned above, international design standards include significant factors of safety that will forgive a measure of inferior construction practices and materials.
  

... but, going back to the top, if this runway failure is as described in the article (a 'punching' failure), this failure could well be the harbinger of a chronic decay of the runway, now underway ... unlikely that it is an isolated failure, but representative of how the entire runway was constructed.

... open 6 years now, major deficiencies at Suvarnabhumi Airport continue to mount ... these are not the isolated sort of corrections expected at the opening of new projects ... these are deeply flawed, fundamental systems deficiencies reflective of a broader mentality ... that is a concern.

... the Thai government is trying to remedially correct them, which is always inferior to doing them correctly in the first place ... leaky roof ... insufficient air-conditioning ... fire safety violations ... too few bathrooms ... radar and air traffic control system failures ... back-up power system failures ... spalling runway concrete ... insufficiently drained, highly expansive subsoils ... under-designed passenger capacity ... forget the ongoing operational problems, this is just the hardware.

... the world's latest technology, most experienced consultants and best contractors and suppliers were available to Thailand in launching it's greatest public infrastructure achievement to date ... Thailand's front door and calling card to the world is suffering signs of obsolesence ... it is 5-1/2 years old.

... anything anyone needs to know about this nation, doing business or living here, is neatly packaged in the story of the building of Thailand's Suvarnabhumi International Airport ... a remarkable story, truly.

Good info.

I'm not a structural engineer but even I'd be wary of building anything on top of a swamp....especially an airport.... and especially in Thailand.

I concur.

I wonder if the number of times it has been closed for repairs is normal

Good post.

[Skywalker69]

Whats are the lives from a crash of a jetliner compared to the amound of tourist dollars anyway.

More news like this needs to be circulated in newspaperws around the world along with unsolved murders of foreigners and all categories of crime.

The more newspapers that are circulated around the world with negative news surrounding Thailand, the better. Perhaps it will cause them to finally get their act together.

Constantly hitting them hard in their pocket books is the only thing that just might get their attention.