Airport Impressions

[Guest]

This trip bc sydney to sing with sia love the service unfortantly no bc sin to bkk.
Bkk to kl bc luthansia bc sia kl to sin

[Stewart]

This trip bc sydney to sing with sia love the service unfortantly no bc sin to bkk.
Bkk to kl bc luthansia bc sia kl to sin

In English please??

bc?
to?......ooops, that is 'to'

[katoeylover]

bc - business class?

[Guest]

(Stewart @ Feb. 11 2007,17:27)

This trip bc sydney to sing with sia love the service unfortantly no bc sin to bkk.
Bkk to kl bc luthansia bc sia kl to sin

In English please??  

bc?
to?......ooops, that is 'to'

I was going to ask the same thing

[Guest]

Sorry guys business class = bc

syd to sin by singapore air bc only way to fly i am not paying for this part of the trip

Sin to bkk on thai econ
Bkk to kul on luthansa bc again
Kul to sin on singapore bc again
well and you already know what the home trip going to be

[rxpharm]

Committee Report issued re: taxiway and runway cracks, The Nation Feb. 13/07







SUVARNABHUMI CRISIS
Cause of problems now clearer, but no answers

'No need to close airport'; firms blamed but not named; 'foreign experts needed'

Water seepage into layers of sand beneath Suvarnabhumi Airport is partly responsible for cracks and ruts in areas where heavily-laden planes manoeuvre, according to an investigation.

The Tortrakul Yomnak fact-finding committee said yesterday seepage was responsible for at least 80 per cent of taxiway damage.

But the runway cracks stemmed from a different root cause, the committee findings said. Surfaces of both runways were supposed to be coated with polymer to increase strength. The probe discovered three-thirds only of the 4,000 metre-long runways were coated.

"It's a design problem. The designer probably wanted to save costs but they forgot we have to use the other end of the runways for take offs when the prevailing wind changes in the cool season," Tortrakul said. "We can probably do away with replacing surfaces because we found no structural damage."

According to the committee, there is no need to close the entire airport. But, the committee was unable to recommend how water could be drained to minimise the potential spread of cracks on taxi lanes and taxiways in the near term, or how to improve drainage to eliminate the problem.

"Technically, there are many ways to drain the water. Other experts should determine the best way with the least shortcomings and lowest costs," committee foundation engineer Suebsak Prom-boon said. "I assume our committee's mandate expires today."

It remains unclear if other factors - such as subsidence - may have contributed to the cracks or represent a host of additional problems.

Committee soil expert Prof Dr Surachat Samphantarak said airfield settlement will not cease after draining because it is built on a layer of soft clay.

He said although clay immediately below the airport structure had been strengthened a decade ago by prefabricated vertical drainage (PVD) - draining water from the layer - untreated, deeper clay would continue to settle.

It may subside faster than the natural rate because it now has to bear the weight of the entire airport.

"Slowly but surely the clay is settling," Surachat said. "If the pavement is not strong enough we may have differential settlement in different areas. Swampy soil subsides at different rates," he said. That can result in more ruts and cracks.

"I also doubt if the PVD technique was done right. How do we know the contractors completed the drainage process. There is no data supporting the [contractors'] claim settlement in the treated soil layer was stopped [before paving commenced].

As a result of uncertainty, Airports of Thailand (AOT) president Saprang Kalayanamitr announced yesterday he will suggest the government retain international experts to inspect the airport and advise on solutions for both the airfield and passenger terminal.

"Nobody can guarantee anything today," Saprang said. "This [Tortrakul] committee has had only two weeks. The [pavement] problem will certainly continue into the future and we need help from foreign experts. But the government will have to decide if this is the way it wants to proceed because hiring experts may involve a lot of money. I was told there are few [companies] in the world that have the adequate expertise."

The affected taxi areas appear to share a common trait, Suebsak said. Water from heavy rain during construction and additional flooding after completion entered the drainage system and seeped into the 1.5-metre-deep sand layer below the pavement. Trapped water mixed with sand destabilises the sand layer, causing cracks on the surface.

While it appears ruts and cracks are confined to about 80,000 square metres of airfield now, experts said it was likely damage could spread to most of its two million square metres.

That is owing to increasing traffic and because the layer is already saturated.

A drainage solution is needed before the next wet season. "I say most of the taxi lanes and taxiways have been trashed," Suebsak said.

Experts said the key issue was that water should never have seeped into the sand layer and suggested drainage systems were "clearly not designed properly".

"The designer probably forgot the two-year period of pavement construction was long enough for a lot of rainwater and other water to get into the sand layer," Suebsak said

The committee could not provide the names of the designers.

Lack of information and cooperation from AOT staff and board members was cited as a "major stumbling block" affecting problem solving and operations.

"We were frustrated we didn't get the information we asked for," Saprang revealed. "But now I have removed people who were part of the problem. I hope the situation will get better with the new people I have put in charge."

Nantiya Tangwisutijit

The Nation

No word on how this may affect the decision to reopen Don Muang - likely not that many airlines will move back as it is strictly voluntary at the moment.

TIT!

[Snick]

To sum up

No one knows what going on, since their do not seem to be any final plans. What plans their are the employees of AOT will not hand over to the directors and inspectors. No one knows what processes were used during construction, if they were the correct processes, and if the contractors didn't just cheat. This includes the runway subsurface, the electrical work, the wielding, the railway line, etc..

The runways may or not be usable, since no one has any idea what process was actually used on the subsurface, and the sand base may or may not be eroding due to the presence (or not) of water.

The terminal may or not overheat and catch fire during the next few months, since the refrigeration electrical units are located in a place where they are likely to overheat.

If it does catch fire it is unknown what would happen since an evacuation plan has never been tested, even if one exists. Nor are exit signs clearly marked.

When the rainy season arrives it is not known if the terminal roof will leak or not.

20% of the air bridges are broken - but no one knows why yet, so they can't fix them or know if the rest are in trouble.

On the bright side, it does seem to be the nail in Thaksin's coffin.

[rxpharm]

Snick, you've done an excellent job - I was thinking about how to sum up all the news reports, you've pretty much nailed it. There are some people who still think this is still all strictly political propaganda to make Thaksin look bad, but there are enough problems that cannot be faked and are real.

Anyway, just need to wait and see how they will fix the problems - after spending 150 billion baht building this one (about 3.75 Billion USD when the exchange rate was 40 Baht:1 USD the good old days).

Mardhi hit the nail on the head when he said he wonders how much of the 3.75 billion ended up in BMW/Mercedes/Rolex show rooms instead of actually building a world class high standard airport.

TIT!

[Snick]

My Thai friends told me they took 30% off the top...I think the take was even higher !

There is not a single aspect of the airport that is not corrupt.

They overpaid for the bomb scanners, bought more than they needed, and formed a separate company to sign off on the deal ( which they did in a day and got millions of $$$ for )

The luggage carts costs are insanely high ( I think I heard $500 USD each )

The security contract is exorbitant, and is locked in for 10 years.

King's group got 50% more retail space then the paid for

The Air Conditioning contractor was an ice making company, with listed assets of $50,000 USD

etc, etc, etc....

[bangkoksins]

I have said it before and will say it again. This whole thing is political.

I would not bother too much with any media right now as the guys in power do not even know what is happening, and as I also said previously some journo's with big names seem to have a personal agenda against Suvarnabhumi.

This issue is no longer about the airport. This is now about International confidence in investing in Thailand.
 
I suggest we do not sum up (especially suming up newspaper reports we can not vouch for) without solid evidence.

I can claim stuff you would find incredulous, from sources you would find incredible, yet I do not as there is too much politics involved with this entire debacle.

As I said in many posts ago. Follow the money. Who is losing money? Answer that (it aint a difficult question) and it becomes a lot easier.

[mardhi]

To a degree of course its political - just look at our own employers and when something goes wrong, the last guy to have left always gets the blame for it even if it was nothing to do with him. Comments along the lines of "well its a good thing we got rid of him and wonder what else he f*&^%d up" normally follow to justify how on top of things the bosses are.   Thats human nature, you deflect attention in politically charged companies and blame the guy who cannot defend himself.  I have seen it happen countless times.    

So fast forward to the white elephant now known as "so-who-can-we-blame International airport" and everything gets blamed on the previous government of the day.   Yet do you seriously expect Khun T had any clue about the engineering details of sand layers 10m below the runways - of course he does not, he is not an engineer for starters, he just wanted a good job done to make him look good - however somebody has seriously f*&%^d up with the engineering overseeing of the whole project.   Lets not forget that the owner has not actually built an airport before so their engineers probably know as much as Thaksin.  Thats why when you see a huge building going up, you have plastered on the wall, the names of countless different engineering companies that DO know about this kind of thing and they work under a managing contractor and seperate architecht firm.  However as much of this was done by Thai contractors, I seriously doubt they had the balls to say "hang on a minute, this is going to be a disaster" as its not a Thai way for the top guy to lose face.    Simple really.  

Cheers
Mardhi

[Snick]

And I say its corruption. Corners were cut and the people who got the contracts were never the best qualified (or even qualified at all).


Interestingly I had lunch with two architects today, one Thai one Foreign, and when I asked about the airport they both agreed that foreign experts need to be brought in and that everyone in the country is busy pointing the finger at some one else.

[TTChang]

(Snick @ Feb. 08 2007,08:30) The old 500 Baht Airport Fee (for international departure) is now 700 Baht  It will be added to all new tickets.  
(I Think) If you bought a ticket before Feb 1st for departure after Feb 1st, you will have to pay the 700 Baht AT THE TICKET COUNTER,

Left LOS last friday.  Wasnt asked to pay anything - ticket purchased in December.  

Presumably Etihad Airways paid my 700 baht, which I'm now saving for a 'rainy day barfine' on my return in May/ June !! 

[rxpharm]

From Bangkok Post March 11/07 - an explanation of why there are problems with the taxiways and runways at the new airport. It is a real problem and not an imaginary political plot to make someone else look bad.

Here is the link:

Distress in the Tarmac

DISTRESS IN THE TARMAC

Because the airport site is located in the floodway of Bangkok's eastern suburbs, it requires both effective flood protection and drainage systems to avoid problems caused by water seepage into the sand blanket under the airport's taxiways and runways, writes PROF WORSAK KANOK-NUKULCHAI



Last October, when the first sign of rutting was spotted in five of the six taxilanes and in one taxiway at the Suvarnabhumi International Airport, the Engineering Institute of Thailand (EIT) assigned a team of experts to join the preliminary investigation. The investigation revealed that the damage was caused by the premature failure of asphalt base course due to the separation of asphalt binder from aggregate surface in the presence of moisture, commonly known as "stripping". It was quite evident from the milled damage area that water seeped from the sand blanket underneath the cement-treated base (CTB) through expansion joints.

The key question is: How, and also how long, has the water been trapped in the sand blanket?

This article intends to provide technical facts to the readers who want to understand what really happened to the airfield pavement of this brand new airport.

Figure 1: Typical distress in the taxiways and taxilanes.



WORRYING OBSERVATIONS

On 27 October 2006, about 2-3 weeks after the official opening of the airport, the first signs of distress were spotted at several locations in the taxiways and taxilanes, in the form of rutting, rutting with shattering and split, and rutting with hairline cracks (figure1). Since then, a similar pattern of failure has developed heavily in five of the six taxilanes and along the east parallel taxiway. Although both runways are still in good structural condition, plastic deformation of the asphalt wearing course was observed near the takeoff position. The extent of the damage is summarised in the table above.

Suvarnabhumi airport covers an area of 20,000 rai (3,200 hectares). In its first phase, the airfield serves its hourly 112 flights with two runways, six taxiways and six taxilanes. The tarmac consists of three layers of asphalt concrete, namely the base course (23 cm thick), the binder course (6 cm thick), and the wearing course (4 cm thick). Underneath are four layers of the cement-treated base (CTB), 18 cm. thick each, sitting on top of the sand blanket (approximately 80 cm thick) left over from the ground improvement process.

Excavation to test the connectivity of the trapped water.

Plastic deformation was observed on the wearing course at the turn-around segment of the taxiway leading to the takeoff position of the runway (Figure 2). This location is normally under maximum load when the plane takes off with a full load of fuel. The high shearing stress that causes plastic deformation was imposed by braking, accelerating or turning traffic. Plastic deformation is greatest at high temperatures, especially for the AC 60/70 binder grade used in this case. The occurrence of the plastic deformation at this location is therefore a common phenomenon and only routine maintenance is required to repair this type of distress. Aside from this surface distortion, both runways are in good structural condition.

Initial investigation was made by coring the asphalt concrete pavement at a diameter 100 mm throughout its 33 cm thickness from the damaged areas (Fig. 3). The following observations can be made:



- All core samples from damaged area show evidence of asphalt stripping at the base course, a typical effect of soaking water, while core samples from undamaged areas show good condition.

- The water had infiltrated into and confined in the asphalt concrete base course for a long period. Thus, the base course has been immersed in and impaired by the water.

- As a result of asphalt stripping, asphalt binder was separated from aggregate surface, leading to premature loss of strength and stability of the base course.

- The load of the aircraft had then impaired the failed asphalt concrete pavement, causing rutting on the surface.

Based on the core samples, laboratory tests have indicated the correct job mix and aggregate gradation of the asphalt concrete material. This was also confirmed by a separate test at the Highway Department.

To expose the cement-tested base (CTB) for visual inspection, an area of asphalt concrete pavement was milled at the damaged area of the taxilane. It was evident that there was no sign of damage or subsidence in the CTB. However, traces of water seepage were clearly observed (Fig 3) along the rim of the expansion joints in the CTB. This evidence of seepage further hinted that a large quantity of water might still be trapped in the sand blanket.

On January 31, a test pit (Fig 3) was dug on Taxiway T11, where damage was found to be extensive. After the excavation went through CTB and exposed the top surface of the sand blanket, water seeped through the sand immediately until the water level reached about 20 cm above the sand blanket (or roughly at +0.0 MSL). The water stayed at that level even when attempt were made to clear the water.

Interestingly, to prove that water in the sand blanket is fully confined with no connection outside, a deep excavation was made nearby, but outside the pavement area. After the excavation, the dug hole was completely dry. No sign of water from the sand blanket had receded into this empty hole.

Meanwhile, Highway Department experts have tested the samples of sand and CTB from this test pit and reported that all materials tested have met the standards.

Figure 2: Surface deformation of the runway.



HOW WAS THE WATER TRAPPED?

Based on the official report of the investigation committee appointed by Airports of Thailand Public Company (AOT), the following reasons had been given for the trapped water:

1. Runoff of rainfall water was collected and retained within the airport compound in the pockets of sand used to fill fishponds, swamps and waterways prior to the airport construction. Water from this source might find its way into the sand blanket.

2. Surface water spilled from the drain age canals, during the flooding period, over the top soil around the unpaved neighbourhood into the sand blanket.

Figure A1: Natural and consolidated soft clay deposits.

3. Surface water once trapped underground was not able to escape due to the lack of a subsurface drainage system. This was aggravated by the blockage of culverts and other underground structures.



4. Based on soil boring records, thin sand layers may exist originally within the soft clay layer at a level about 10 metres deep. Some of these sand layers may cross path with the leftover PVD, thus allowing running shallow ground water to seep upward into the sand blanket.

On the last point, some geotechnical experts argued against this possibility. At the end of the PVD preloading, the extra surcharge consisting of crushed rocks was removed. Thus, it is no longer possible for water to move up to the surface through the PVDs against the hydraulic gradient and against gravity at the end of consolidation process.

Figure A2: Consolidation process of soft clay under the airfield pavement.

In addition, there is hydraulic back-pressure from the trapped water in the sand blanket making it impossible for such hydraulic upward flow to occur.

Because the airport site is located in the floodway of Bangkok's eastern suburbs, it requires both effective flood protection and drainage systems. The aim is to prevent flooding from flash floods, as well as to drain away rainwater in the catchments of the airport compound. The design of the polder system includes the perimeter polder dike, internal drainage system, two pumping stations and a perimeter road (Fig 4).

Basically, the internal drainage system for runoff water consists of:

1. The unlined primary canals and reservoirs both with the bed at -1.90 m MSL. Based on the design criteria, water level in the primary canals and reservoirs must be maintained not higher than -1.40 m MSL.

2. The secondary canals with concrete linings. The canal bed of the secondary canal is -1.15 m MSL. It is designed to be dry except during the raining.

The primary and secondary canals are interconnected by ditches to ensure that the runoff water from the pavement area will flow under gravity towards the two pumping stations located at the south corners of the site. In the operating manual, water in the primary canals and reservoirs must always be controlled at the pumping stations to ensure that the water level is maintained at -1.40 m MSL or lower.



With the design assumption that no rain water runoff can leak into the sand blanket, no subsurface drainage system exists to systematically drain trapped water from the sand blanket. This might be a weakness in the design criteria of the airfield pavement.



Figure 3: Illustration of milled pavement in the taxilane T11, a core sample of asphalt concrete, trace of the water seepage at CTB joint and the test pit.

WHAT'S NEXT?

In its press release issued on 15 February 2007, the Engineering Institute of Thailand (EIT) strongly recommended that, similar to a first-aid treatment, trapped water should be drained out urgently to minimise the potential spread of cracks on taxi lanes, taxiways, and even on runway. This immediate action should be carried out with the consent and cooperation of all concerned parties including the project management consultants, the designers and the contractors.

Alternatively, the AOT should seek temporary protection from the court to implement the required first-aid treatment without damaging its rights under the contract. Meanwhile, it was reported that the AOT plans to commission a team of international experts to carry out an in-depth technical investigation in order to recommend long-term remedies.

Prof Worsak Kanok-Nukulchai, PhD is dean of the School of Engineering & Technology at the Asian Institute of Technology. He is also vice-president of the Engineering Institute of Thailand and a member of the Royal Institute.

Illustration of taxiways and taxilanes.



GROUND IMPROVEMENTS

Suvarnabhumi Airport compound is situated on formerly agricultural land, fish farms, swamps and waterways. A thick deposit of soft clay is found over 10 metres deep, with 100-120% water content, on top of medium stiff clay and stiff clay with water content of 50-90% and less than 50% respectively.

Soil is a multiphase system, comprising a solid phase (soil particles) and a fluid phase (air and water) called the pore fluid. For soft clay, the higher the volume of the fluid phase, the weaker and more compressible the soil mass. Therefore, any reduction of water in the pores of the soil, which decreases the volume of the soil mass (Figure A1) and subsequently increases the particle-to-particle contact, increases the strength of the soil and reduces its compressibility at service stage.

To be suitable for airfield pavement, pore water in the soft soil must be squeezed out to result in water content around 80%. Thus, the soft clay is transformed into medium stiff clay. This consolidation process can be accelerated by a modern technique using Prefabricated Vertical Drains (PVD).

PVD is a plastic tube core wrapped in a filter jacket, made of non-woven polyester or polypropylene geotextiles or synthetic paper. PVDs drain soil by squeezing out pore water, a process that can be accelerated by adjusting the spacing of PVDs. In this process, water flows a lot more quickly horizontally towards the drain and then vertically along the drains towards the permeable drainage layer at the top. The step-by-step procedure of consolidation using PVD is illustrated in Figure A2.

Figure 4: Profile of the flood protection and the drainage system.
Overview of east runway, taxiways and the drainage system.




Quite technical explanation, but it seems to indicate the initial designers of the airport assumed that there would be no water seepage coming into the sand blanket underneath the runways and taxiways. The other possibility might be substandard materials or methods might have been used that allowed water seepage to happen - but this is not proven.

Anyway, the problem MUST be fixed before it gets worse to make sure the airport runways and taxiways will be safe for all flights. You can only imagine what cracks on the runway would do to a plane landing or taking off.

TIT!

[Torurot]

Blimey, Crikey & gosh, there's a lot under your feet when your flying. Guess 300+ tonnes puts a wee bit of stress on things, and who wooda thought it ever rains much round outer Bangkok. Shit, even Mrs Marsh knew it got into the chalk.