Supreme engineering combined with tribological expertise

>Wherever moving parts have to function smoothly under high loads, reliable lubrication is a must. The new lifting bridge Pont Jacques-Chaban-Delmas near Bordeaux in France is a case in point. Klüber Lubrication was commissioned to provide specialist lubricants to all its friction points and met expectations by applying three speciality lubricants which exactly matched the requirements of the works.

>The Pont Jacques-Chaban-Delmas is an impressive lifting bridge built of concrete and steel. Opened in spring 2013, it links two districts of the city of Bordeaux across the Garonne. At 433 metres long and 43 metres wide; it provides two lanes for cars in each direction as well as paths for pedestrians and bicycles on each side. Two additional lanes in the middle of the bridge are reserved for public transport. The most impressive part of the bridge is its 117 metres long middle span, which is lifted to allow the passage of large vessels calling at the port of Bordeaux. Lifted about 120 times per year, the bridge takes about 11 minutes to reach its lifted height of 53 metres.

>The lifting bridge's most prominent features are four freestanding pylons reaching up 77m from their bases. It is these pylons that have to support the lifting middle section's full weight of approximately 2750 tons. The lifting mechanism of the bridge works like a giant elevator: counterweights in the form of four metal bars with a total weight of 2694 tons run up and down inside the pylons. They are connected to the middle section of the bridge by sets of cables running via pulleys four metres in diameter, which are mounted at the top of the pylons. In the bases of the pylons, the cables are wound onto drums. The lubrication of this extraordinary design with its many moving parts proved demanding, which is why Klüber Lubrication was entrusted with all friction points.

>All moving parts in this mechanism are subject to extremely high loads and their lubrication must be reliable and failure-proof. Some of the friction points are difficult to access and relubrication intervals need to be as long as possible. Moreover, as Bordeaux is situated near the Atlantic coast, its air is rich in salt, so significant corrosion protection is required. Another requirement of the client was to use only a small number of different lubricants to simplify lubricant usage.

>Following an analysis of the system, Klüber Lubrication recommended three special lubricants offering the characteristics needed to optimally satisfy the individual requirements of the numerous friction points involved. The bearings of the cable drums and the winches required a grease with a very high viscosity; Klüberlub BE 41-1501 is a special grease for rolling bearings running slowly under heavy loads. It is based on a highly viscous base oil, special soap thickener and extremely effective pressure and anti-wear additives.

>Klüberplex AG 11-462 was specifically developed for marine applications; wet atmospheres and salty conditions. Klüberplex AG 11-462 is resistant to high loads and provides excellent corrosion protection and wear protection even at low temperatures due to specially selected solid lubricants and additives. Visual acceptability is improved through the use of a white lubricant and lubricant coverage is simple to inspect. Klüberplex AG 11-462 offers versatile uses across gear rim and pinion drives, bearings; the couplings, joints, locking mechanisms and guideways of the lifting middle section are also lubricated with Klüberplex AG 11-462 simplifying lubricant usage, stocking and selection.

>For the gearboxes Klübersynth GH 6-320, a synthetic high-temperature gear oil based on polyglycol was selected for its high resistance to scuffing and micropitting as well as very good wear protection to extend gear and bearing life. Thanks to the excellent anti-ageing and oxidation resistance of its synthetic base oil, Klübersynth GH 6-320 attains a much longer service life than mineral oil-based lubricants resulting in longer service intervals. The optimised friction behaviour of the polyglycol base oil reduces power loss and improves gear efficiency, whilst its excellent viscosity-temperature behaviour supports the formation of a sufficient lubricant across a wide temperature range.

>The reliable lubrication of moving components is essential to protect installations against failure, especially if they are as large as in this example. Klüber Lubrication has the comprehensive expertise required and actively assists from the planning through commissioning to operation.