Racing against the clock

FRIDAY, JUNE 8, 2007. DRESDEN AIRPORT WILL BE CLOSED FOR EXACTLY 64 HOURS AS BILFINGER BERGER ROAD LAYS THE NEW RUNWAY. KEEPING AN EYE ON THE CLOCK ON A HOT AND HECTIC WEEKEND

Friday, 15:00
The pilot of the Condor flight to Antalya gives the Airbus A320 full throttle. The passengers feel every vibration: over the decades, the effects of heat and frost have transformed the 2.5 kilometers of runway into a bumpy ride. It’s the last departure for this weekend. The rest of the flights will be diverted to Leipzig, and Dresden Airport will be closed. The new runway is 60 meters wide and immediately adjacent to the old one, the concrete will be cast over four weekends, one strip of 15 meters being laid each weekend. The new runway will be 2.8 kilometers in length, the surface course 40 centimeters thick. All of which means that 16,000 cubic meters of concrete—1,600 truckloads—will have to be cast.

That leaves just 64 hours for a genuine tour de force.“We’re casting concrete from midnight,” states foreman Werner Eiserloh, a burly man with a gray moustache.“Until then it’s all about preparation!” His people are in the process of pumping 2,800 liters of sealing compound into the tanks of a concrete finisher. Two of these 70-ton giants are under the charge of Eiserloh, whom his men jokingly refer to as the “laying magician.”“Laying” is what the experts call placing the concrete.

15:55
Workers have begun to position steel profiles, the formwork for the runway. Surveyors lay out a contact line. Later, the machines will feel their way along this guide wire. Eiserloh constantly measures the distance to the formwork: better safe than sorry. Christoph Adler, 41, Branch Manager of Bilfinger Berger Road in Dresden, hurries his BMW over the 15-meter wide strip that was cast in the first weekend in June and talks to surveyors and foremen. The site manager maintains his calm and friendly demeanor, even under pressure. It is oppressively hot. “I’m worried about the weather,” says Adler. “We could have some problems if there’s a thunderstorm.”

Saturday, 00:05
The building site is bathed in floodlight. Huge piles of sand and crushed stone stand ready. Three mobile mixers outside the gates of the airport spew out concrete. Twelve kilometers away at the railway station, three freight trains disgorge 4,000 tons of cement. Twelve trucks shuttle back and forth day and night. Another 50 trucks on the building site deliver the concrete to the laying teams. There are two of them, each with two concrete mixers working in sync - that’s the only way the punishing schedule can be met. The teams start in the middle of the runway and set off in opposite directions. A truck dumps concrete in front of Eiserloh’s leading concrete finisher, which is laying the 33-centimeter thick lower top course. The steel colossus begins to shake as 30 bottle-like vibrators ensure that the concrete flows into the formwork, where it is compacted by a compression and screed board weighing one ton. The machine, which crawls along on chains, keeps pressing steel anchors as long as an arm into the viscous mass. Excavators unload even more concrete behind the machine; the second concrete finisher uses this to lay the topmost surface course, seven centimeters thick. A worker follows, making fine grooves in the fresh surface using a hard brush. “Sometimes you just can’t beat doing it by hand,” says Christoph Adler. “The brushstrokes ensure the optimum grip for aircraft tires.” The finisher teams drag tents as large as those used in the Oktoberfest behind them—they are to protect the fresh concrete from rain.

05:10
The sun rises, a red ball in the cloudless sky. Site manager Adler is content. “It was a good night,” he says. The two finisher teams each cast concrete at a rate of 60 meters an hour and are already 600 meters apart. Adler leaves the site for a couple of hours sleep. The work goes on: the second shift continues the laying.

17:04
Glowering dark clouds have been gathering for hours. Heavy drops begin to fall. The teams have to suspend their work.

17:32
It is hailing. The 120 meters of tents immediately behind the machines protect the fresh concrete. Behind the tents, though, the runway is unprotected and for 100 meters it is pockmarked with flat indentations. “Damn, we'll have to repair that,” groans Eiserloh. But there's no time to moan: deep puddles have formed in front of his concrete finishers. “Get pumping, quickly!”

18:17
The rain has stopped, the water has been pumped away, and it’s time to get moving. A little later Eiserloh hands his finisher trains over to another foreman: change of shift.

Sunday, 05:15
Good progress was made in the night. By the time the sun rises, 2,000 meters of concrete have been cast.

09:00
Eiserloh has been on the site for three hours already when his team reaches the northwest end of the runway. “Well on schedule,” beams Adler. But the southeast team is lagging behind. The temperature on the previous day had risen above 30 degrees Celsius, so the surface of the concrete dried quicker than the men with the brushes could keep up with, resulting in defective grooves. Fifty meters had to be dug up again and concreted a second time.

14:00
Yet another problem: the surveyors are behind with marking the joints. Cuts several centimeters deep have to be made into the fresh concrete every five meters because it shrinks and cracks as it solidifies. Adler puts the pressure on. Friendly, as ever, but firm. “So many things are going on at the same time,” he says. “And with this heat the teams have less time because the concrete hardens quicker.”

18:10
Adler walks over the new strip. The joints divide the concrete neatly into squares of five by five meters, and all squares have their own stamp. “The airport guys will get a great runway,” he says quietly.

23:55
The second team reaches its goal just before midnight. On time. In 48 hours the huge machines and their operators have placed 1,600 truckloads of concrete in extreme heat. During the rest of the night the formwork will be dismantled and cleared away.

Monday 07:35
The airport is reopened and the first plane takes off, towards Zurich, Switzerland. Christoph Adler hurries to the next meeting: there’ll be another race against the clock next weekend.

The teams remained on schedule on the following two weekends in June as well: at the end of the month the workers celebrated the successful completion of the concreting works with a barbeque and free beer in the Waldmax, a popular country inn near Dresden. On August 30, a Lufthansa Boeing 737 was the first plane to take off from the new runway.

(Text & Photos: Paul Hahn)