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To Get to the Other Side PUBLIC ACCESS

Sometimes You Have to Plan How to Cross Your Bridges Before You Come to them

[+] Author Notes

Executive Editor

Mechanical Engineering 128(04), 40-42 (Apr 01, 2006) (2 pages) doi:10.1115/1.2006-APR-4

This paper discusses engineering design ideas employed by P. Wirzius Heavy Assembly GmbH of Hinden, Germany, to transport heavy loads across states. In order to find a safe way to cross its bridges, Wirzius enlisted a specialist in getting heavy objects safely to their destinations, Greiner Vehicle Technology, an engineering company based in Neuenstein, Germany. Greiner says it designs systems for transporting large machinery by road or rail. Working with Wirzius, the Greiner company devised a plan to transfer some of the extraordinary vehicle weight to a temporary track system that would channel that part of the load directly to the bridge piers. Engineers working in 3D simulated the system in motion and avoided problems, like collisions, that would otherwise have needed correction later. Crews from Greiner and Wirzius tested the system at the former Butzweilerhof Airport in Ossendorf. A transport vehicle had to transport 295 tons of ballast across a 14S-meter track. The next day, they repeated the test as a demonstration for French motorway authorities.

There's a song, "Sur le Pant d'AlIignol1," about p eople-from dames and messieurs to ga rden ers, laundresses, and vine trimmers-all dancing on the bridge at Avignon. It's an old song with a catchy melody. It probably refers to a one-time landmark bridge built during the 13th ce ntury on th e site of an earli er one laid down by a saint. The bridge is gone now, but the song remains, to remind us that bridge-building goes back a long way in France.

The old bridges have not all vanished. There are many historic structures in daily service on French roads. T hey can hold up under considera ble dancing and moderate day-to-day traffic. T hey were never expected, though, to bear tru cks carrying machine parts that weigh almost 300 metric tons. Few bridges of any age are ready for that.

Aubert & Duval Group, a supplier of parts, steels, and other materials to a range of industries, had to find transport for eight machine components of that scale. They were castings for new 40,000-ton forging presses, which th e company needed to move fr0111. a Mediterranean port to its new fac tory in Pam.iers.

The presses will forge fan disks for tu rboj et en gine manufac turers, and it is exp ected that some of the engines will power Europe's new supersize j et, the Airbus A380. T his operation, called Airforge, joins another Aubert & Duval plant already operating in Panciers.

According to Bernard Finas, proj ect manager for what the company calls " the Airforge 40,000-ton proj ect," the presses have been assembled and are due to begin operating in July.

Aubert & D uval ord ered the machines from Siempelkamp Press Systems of Gernuny. T he fo rgings and castings were the work of Japan Steel Works, whi ch sent the fini shed parts to Port la Nouvelle, near N arbonne on the Golfe du Lion on th e south coast of France.

P. Wirzius Heavy Assembly GmbH of Hind en, Germany, had the job of transporting the presses overland and assembling them at the fac tory in Pamiers, south of Toulouse.

Engineers and workers (Ieftl guide an extraordinary load across a bridge on the route between Port-Ia-Nouvelle and Pamiers, France. Hydraulic lifts on the trailer transfer about 140 metric tons of the load through the improvised track directly to the bridge piers. long spans on a curve (abovel proved to be a special test for the system, which was developed by Wirzius Heavy Assembly and Greiner Vehicle Technology.

Grahic Jump LocationEngineers and workers (Ieftl guide an extraordinary load across a bridge on the route between Port-Ia-Nouvelle and Pamiers, France. Hydraulic lifts on the trailer transfer about 140 metric tons of the load through the improvised track directly to the bridge piers. long spans on a curve (abovel proved to be a special test for the system, which was developed by Wirzius Heavy Assembly and Greiner Vehicle Technology.

Some of those historic bridges made it impossible to take the most direct route from the seaport to the fac tory, so Wirzius mapped out a route th at, altho ugh roundabout, ran on maj o r hi ghways. Even on the modern roads, however, a vehicle of more than 400 tons needed special waivers from French authorities before it could set out. Delivering the presses, though, was considered inlportant to the nation, so the trip received a green light.

According to Wirzius, the route was about 230 km by road. The route included five crossings that were not up to the load of a trailer bea ring one of the huge press parts, a gross weight of 430 tons.

To find a safe way to cross its bridges, Wirzius enlisted a specialist in getting heavy objects afely to their destinations, Greiner Vehicle Technology, an engineering C0111- pany based in N euenstein, Germany. Greiner says it designs systems for transporting large machinery by road or rail. That, in fac t, is what the company's bridge- crossing solution involved, both road and rail, but not in a conventional sense.

Michael Greiner, the company's e EO, said his en gineers could either strengthen the bridges or find a way to reduce the stress on them. Rather than trying to rebuild or shore up the structures, the company took the second course, which is where the rail part comes in.

Working with Wirzius, the Greiner company devised a plan to transfer some of the extraordinary vehicle weight to a temporary track system that would channel that part of the load directly to the bridge piers.

According to the Greiner company's executives, the timeline of their job for Wirzius meant that they needed to have as many parts of the project as possible taking place at the same time. To make things a little more challenging for Greiner, when it took on the job, the company was switching its design software from a 2-D system to a 3-D product, OneSpace Designer Modeling, fi'om Co Create Software in Sindelfingen, Germany.

A CAD rendering of the hydraulic lift system and track design. Greiner was adopting new 3-D software, from CoCreate, during the project.

Grahic Jump LocationA CAD rendering of the hydraulic lift system and track design. Greiner was adopting new 3-D software, from CoCreate, during the project.

The change went well, according to Michael Greiner. "While we were still designing, we were running the production line," he said. "Some local suppliers were also producing individual components even before the entire design was complete."

Given that the company had to have a workable system ready for Wirzius in less than a calendar year, the jump on production was necessary.

According to Jo ch en Saile r, tec hni ca l d esign er at Greiner, engineers working in 3-D simulated the system in motion and avoided p ro blems, like collisio ns, th at would otherwise have needed correction later.

Crews from Greiner and Wirzius tes ted the system at the former Butzweilerhof Airport in Ossendorf. A transport vehicle had to transport 295 tons of ballast across a 14S-meter track. The next day, they repea ted the test as a demonstration fo r French motorway authorities.

Transport from Port la N ouvelle to Pamiers started with two castings, each lifted by an SOO-ton hydraulic gantry onto a separate Goldhofer platform trailer. Each trailer had 20 lines of swing axles three across and was dr ive n by a trac tor fore and aft. Each trailer also carried a hydraulic ga ntry, with two cylinders in front of the casting and two close behind. T hey would be the means of transferring weight from the road to the track.

The convoy included a fleet of tru cks that carried the parts of the track. Wirzius calls it the R oll -On, Roll-Off system and holds patents for it.

The temporary track was designed to cover spans as great as 60 meters. The first crossing had two central spans of 27.S meters each. T he track-building team began by laying steel mats at load-bearing points on the bridge. The rails over the mats were box girders 1.5 meters high with bolt-and-flange couplings. This bridge needed a total of eight for each side of the track- five that were 10 meters long and three S meters long. With the help of a crane, team members jockeyed the pieces into place.

Once the track was secure, the gantries on the trailer came into play. They extended outward and then brought down steel wheels onto the improvised tracks. The four hydraulic cylinders of the gantry transferred a total of about 140 tons of the load to the track system, which channeled the weight directly to the bridge piers. The bridge surface held the remaining 290 tons.

The team disconnected the tractors and used a tru ckmounted winch to haul the trailers one at a time across the bridge at a rate of about 4 meters a minute. Observers accompanied each trailer to make sure the wheels followed reference lines painted on the road.

The convoy did that five times along the route, over spans of different lengths. The span of one bridge extended almost 60 meters between supports and lay. on a curve.

The trailers progressed on the highway at speeds ranging from 15 to 30 km an hour, and stopped at points along the route, while the teams assembling the tracks prepared crossings ahead. Delivering the castings two at a time, the convoy made four trips in four weeks to get everything to Pamiers.

The itinerary had to be carefully plotted and the schedule kept. Traffic was diverted from the sections of highway that the co nvoy was using. Bridge sections were closed and traffic detoured for a day or more as tracks were laid, crossed, and dismantled. R ail traffic had to be suspended to let the convoy pass a grade crossing.

The trucks carried an identifica tion that read "convoi exceptionnel. The description sounds fair enough.

Each trailer was the size of a barge being pulled by one huge tractor and pushed by another. The trailers were accompanied by a fleet of trucks, motorcycles, and support vehicles. T here were policemen, highway officials, and a cast of engineers, techni cians, drivers, and assemblers. They may not have been exactly dancing, but they were all on the bridge together.

Copyright © 2006 by ASME
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