96 Hours in August

The development of Bremen’s runway 09/27 can be traced back to 1937. This aerial view illustrates the strengthened segments that are provided at each end. (CAB)

Tom Allett spoke to Alice Hossain about Bremen Airport’s decision to close down for the duration of its forthcoming runway resurfacing and lighting project.

About 450 flights will be affected by Bremen’s temporary closure. (KEY-Tom Allett)

While it isn’t completely unheard of, it is still a rare event for a commercial airport to close down completely during a runway resurfacing project rather than carry it out in stages over many nights.
However, City Airport Bremen in northern Germany will do just that for a period that is scheduled to cover 96 operational hours between the evening of Monday August 6 and the early hours of Saturday August 11.
The airport’s current runway comprises the primary centre section which is 6,673 x 147ft (2,034 x 45m) in length, with a 984ft (300m)-long section of reinforced asphalt surfacing at either end to cope with the outsize Airbus Beluga freighters which are regular visitors and have a take-off weight of around 150 tonnes.  The original concrete runway of approximately 2,132ft (650m) was laid down in 1937.  It was extended 1,968ft (600m) to the west in 1939, and by a further 1,868ft (575m) to the east in 1949.  All three of these sections were made up of 9.5in (24cm) concrete slabs.  Also in 1949 a 689ft (210m)-long runway head was added at the eastern end which included a 12in (30cm)-layer of concrete and 13.8in (35cm) of sand.  At the same time a layer of red sand asphalt 4in (10cm) thick was inserted under the centre-section’s concrete slabs, and a 12-13.8in (30-35cm) layer of sand was applied under the remaining sections.
This formed the basis of the runway that subsequently received various layers of bitumen asphalt reinforcements with an average thickness of 15.5in (40cm) in 1963, 1966, 1971, 1980 and 1990.  As a result, the runway’s foundations are now covered with several layers measuring about 2ft 3.5in (70cm) in depth.
Two years before the next resurfacing was scheduled to take place, the airport undertook a detailed study to decide on the best process.  Should it opt for the most common practice of completing the resurfacing work in short sections carried out over many consecutive nights, or take the alternative option of closing down and diverting all flights elsewhere in order to complete the task in the minimum amount of time?
Bremen hired the small but experienced German engineering company, Airport Consulting Engineers GmbH (ACE), to undertake the comprehensive study and subsequent work.  The firm, which has about 20 employees, has previously completed successful runway refurbishments at Frankfurt-Hahn and Malta’s international airport.
Alice Hossain, Bremen Airport’s Head of Communications told Airports International: “The study found that if we closed down completely and allowed the refurbishment work to continue around the clock, as we have a night curfew here, we would only lose 96 operational hours.
“We estimated that doing it this way would be about €1.5m [US$1.8m] cheaper than the alternative and it would be a much more environmentally-friendly choice, especially for our neighbours.”
The development of Bremen’s runway 09/27 can be traced back to 1937. This aerial view illustrates the strengthened segments that are provided at each end. (CAB)

Ms Hossain pointed out that hundreds of vehicles would be needed to complete the task, and the noise and pollution involved with moving each one on and off site every night for an expected three-month period would obviously be much greater than if they could remain in place for the duration.
Having decided on the procedure, the next problem was to choose the best date to carry it out.  Studying past weather data revealed that the first two weeks of August had the lowest average rainfall and, by selecting the latter half of that window, the airport avoided interfering with the busiest traffic.  Nevertheless, no airport wants to send its passengers to another one; not even for a limited amount of time.  There is always the danger that if the customer is exposed to the competition, he or she might prefer it.
Ms Hossain commented: “Some 450 flights and about 39,000 passenger seats will be affected, but the airlines and travel agents have known about the closure since December 2011, so they were able to stop selling tickets some eight months in advance, thereby minimising the number of people that have had to change their plans.  Of course, as this is taking place in August, the amount of business traffic is low compared to other times of the year.”
During the forthcoming work, about 27,000 tonnes of existing runway material will be removed and replaced by 28,000 tonnes of new asphalt, covering a total surface area of about 1,001,043 sq ft (93,000m2).  Overall, some 100,104 sq ft (9,300m2) of surface markings must be put down, but the engineering team has decided that no special friction-related top surface is required.
A significant proportion of Bremen’s runway lights will also be replaced.  This involves work being done before, during and after the asphalt replacement, though the preparatory and follow-up work will take place at night in order to avoid any operational disruption.
Safegate is managing the airfield lighting work and will oversee the replacement of the runway centreline lighting system (RCLS) and the touchdown zone lights (TDZL).  About 500 lights and 22,309ft (6,800m) of cable conduits will be fitted.
The total cost of the resurfacing and lighting work is approximately €5.6 million (US$7m), all of which will be paid from the airport’s existing income; no extra passenger taxes or fees will be introduced to cover the costs.
Weather and engineering work permitting, Bremen is scheduled to re-start flights from 06:00 local on August 11, 2012.
The author would like to thank Alice Hossain and Edda Obi-Ejoh from the media communications office for their help in producing this article.