Major works @ BRU

[DannyVDB]

Dear all,

I am a little bit confused regarding the following message in the newsletter of 11/2014 of BRU:

During summer 2015, Brussels Airport will execute a complete renewal of runway 25L/07R. The construction work will last 4 months in total, with the first two weeks of August as the most critical phase. Therefore during that period there will be a significant reduction of slot capacity.
These operations are part of a general maintenance and renovation program in order to maintain the safe and efficient operation of the runways. The previous renovation works on this scale date from 1985.

I thought there were recently quite some works. What is it they will do - for the first time since 1985! - that they need 4 months (I remember they did some works over the past years, usually in August, but that took only a few weeks).

Second question: what could be the impact of these slot reductions?

Cheers,
Danny

[RoMax]

If it takes 4 months and they haven't done works on such a scale since 1985, it must be really extensive structural work. Would be interesting to have more information on this.

[Airbus A330]

Runway 25L will probably be strenghtened during these works

[DannyVDB]

What does that mean exactly, strenghtening the runaway.

I thought that they already replaced the landing/lighting systems, so it must be more than that ...

D

[flightlover]

The works done to the runway in the past years most probably existed of improving the top layers off the runway. This takes just a few days/weeks depending on how extensive those works are (i.e.: removing the top layer and resurfacing it).

The duration of the works planned for next year suggest works will most probably include the underlying layers also.

[Airbus A330]

Different runways at a same airport don't have necessarily the same "strenght" (I'm not sure if it's the most accurate word).

By "strengthening the runway", I mean increasing the strenght for heavier aircraft and some people told me that 25R is stronger than 25L (maybe one of the reasons why the empty Lufthansa A380 had to land on 25R?).

The duration of the works planned for next year suggest works will most probably include the underlying layers also.

That's what I think.

[jan_olieslagers]

The official data is easily available from the online AIP, but how to interpret these figures? 67 F/A/W/T, 62 , 80 , ... ?

01 014.43° 2 987 x 50 67/F/A/W/T 505314.39N
0042929.68E THR 183 ft
ASPH 505446.54N
0043007.27E TDZ 184 ft
141 ft

19 194.43° 2 987 x 50 67/F/A/W/T 505439.64N
0043004.46E THR 113 ft
ASPH 505312.94N
0042929.09E TDZ 131 ft
141 ft

07R 069.89° 3 211 x 45 62/F/A/W/T 505321.89N
0042855.40E THR 175 ft
ASPH 505356.19N
0043123.88E
141 ft

25L 249.89° 3 211 x 45 62/F/A/W/T 505356.19N
0043123.88E THR 159 ft
ASPH 505320.54N
0042849.53E TDZ 165 ft
141 ft

07L 065.38° 3 638 x 45 80/F/A/W/T 505400.12N
0042734.43E THR 129 ft
ASPH 505445.58N
0043011.76E
141 ft

25R 245.38° 3 638 x 45 80/F/A/W/T 505441.55N
0042957.79E THR 110 ft
ASPH 505356.64N
0042722.39E TDZ 112 ft
141 ft

[Zorba]

Information on Runway PCN decoding can be found here:

https://en.wikipedia.org/wiki/Pavement_ ... ion_number

[jan_olieslagers]

Huh, quick service, as so often - dank u wel !

[sn26567]

Wouldn't it be an opportunity to extend the taxiway until the threshold of 25L ?

[jan_olieslagers]

But that would require a lot more work than redoing the surface and/or the lower layers of the runway - to begin with a second tunnel for the Tervuursesteenweg.

[Homo Aeroportus]

... some people told me that 25R is stronger than 25L (maybe one of the reasons why the empty Lufthansa A380 had to land on 25R?).

Don’t think this was too much of an issue especially for a lightweight A380. A fully loaded 773 at MRW on his way out to take-off affects much more the pavement.

Actually, the required strength of a pavement is a combination of three things :
• the weight (mass) it is to support ,
• the dynamics, i.e. how quickly the load is applied and retrieved,
• the number of passes, i.e. number of times per year that this load is applied on the pavement.

Whether rigid (hydraulic concrete) or flexible (hydrocarbon / asphaltic concrete, aka asphalt/tarmac), the pavement transmits the load to the under layers in an elastic fashion. It is this sandwich as a whole that must be able to withstand the load and the repetition that leads to a permanent set.

Somewhat oddly, runways are not the paved areas that suffer the most. Although the puff (or bang ) on landing is spectacular, the slow moving aircraft on a taxiway or even worse, the long standing aircraft on the apron, creates a much more demanding situation.
This is why at EBBR/BRU the TWYs leading to Cargo (Alpha 6-7) or on the way out to T/O like Bravo 8 have a PCN of 120, 50% higher than the RWY.
Same for heavy aprons like 9 (Cargo) and 55-56 (VVIPs, “West Platform”) with PCN 120.

Although rare, i.e. not significant in terms of permanent set, another bad-day scenario is the following that must be considered to avoid creating cracks or sinking in :
A fully loaded bird takes off and just before V1 goes for an RTO. Fuses deflate a few tires and the heavy A/C returns to the stand. With possibly as many as 5 deflated tires on the same leg of a 773 or 388, you end up having 50% of the mass resting on that landing gear being applied to the pavement via the only remaining intact wheel on that strut. Hopefully the deceleration to stop will be smooth and will not induce an additional horizontal strain on the pavement.

Think also of a heavy, and long, aircraft such as 773 or 388 coming to stop but with an abrupt deceleration. Due to the whiplash effect, the vertical load through the nose gear increases significantly. Example for an A388 at MRW, static load is 40T (at max forward CG) but with deceleration of (standard max considered) 10ft/s² it is now 70T being applied on the pavement, possibly on the footprint of a single tire (then a real bad day).

A monolithic pavement runway has a very long life expectancy but also a much higher cost than an asphaltic one, that is usually good for about 25 years. So if BRU says that the last in-depth re-construction of 25L was back in 1985, it must be due for a complete rehab soon indeed.

H.A.