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When our colleagues at mageba’s local subsidiary, mageba Slovakia s. r. o. (Ltd.), learned of the proposal to build a major new crossing of the Danube outside the Slovak capital – the longest bridge in Slovakia, requiring the country’s biggest expansion joints – they were excited to contribute their know-how and experience to this special project. The bridge is the main structure on the new Bratislava Bypass section of the country’s D4 motorway, which forms part of the Trans-European Transport Network and is therefore of international importance.
In fact, the Danube crossing is just one of a number of structures on the D4/R7 highway construction project for which mageba is supplying a wide range of products, including bearings and expansion joints of various types. The construction consortium, having responsibility not only for design and construction but also for financing and operation for a period of 30 years, is motivated accordingly by the contract to use only structural products that can be relied upon to provide a service life of at least 30 years with a minimum maintenance effort – and mageba is happy to oblige.
The main structure across the Danube is a concrete box girder bridge with a total length, including approaches, of 3000 m (9842 ft) – mostly with spans of about 67.5 m (221 ft) but with six longer spans of between 130 m (426 ft) and 210 m (689 ft). Large expansion joints were required at five locations along its length, each over 30 m (98 ft) long. The required longitudinal movements range between 500 mm (19 in) and 1400 mm (55 in) for each joint, and it was also specified – in keeping with the bridge’s location in a sensitive, ecologically protected area – that the noise emitted by traffic passing over the joints should be very low. Supporting the bridge designers from an early stage, and considering all other specifications and requirements, mageba proposed the optimal expansion joint solution: TENSA®MODULAR (type LR-LS) expansion joints with noise-reducing surfacing. As well as greatly reducing the noise of traffic passing over a modular joint, the noise-reducing (“sinus plate”) surfacing enables the largest movement requirement of 1400 mm (55 in) to be met by a 14-gap joint (at 100 mm (4 in) per gap), rather than the 18-gap joint (without sinus plate surfacing) that would be required at 80 mm (3 in) per gap. This is a welcome optimisation for what has become the largest-movement expansion joint on the Slovakian road network.
This impressive structure is just the latest in the long list of bridges over the River Danube for which mageba has provided a wide variety of bridge bearing, expansion joint and SHM solutions to date – such as the Pentele Bridge (TENSA®FINGER cantilever finger joints, 2007), the Danube Bridge Sinzing (ROBO®CONTROL “Portable” SHM system, 2008), the Traismauer Bridge (TENSA®FINGER sliding finger joints and cantilever finger joints, 2010), the Margaret Bridge (TENSA®GRIP single gap joints and TENSA®FINGER cantilever finger joints, 2010), the Rákóczi Bridge (POLYFLEX®ADVANCED Type PU flexible plug expansion joints, 2015) and the Mosoni Duna Bridge (RESTON®SPHERICAL bearings, LASTO®BLOCK elastomeric bearings and TENSA®MODULAR expansion joints, 2017).
With the noise-reduced TENSA®MODULAR expansion joints newly installed on the Bratislava Bypass – and many other mageba structural components used in other structures along the highway construction project – the construction consortium can relax in the knowledge that these key structural elements will serve their purpose well for at least the next thirty years, after which they will no longer be their responsibility. And the “quiet” expansion joint solution implemented on the bridge will help maintain the solitude of this beautiful and ecologically protected environment, enabling visitors to the area to continue enjoying the experience for just as long.
Bridge designer: Dopravoprojekt, a.s. TORROJA ENGENIERÍA, S.L.P.
Contractor: The consortium D4R7 Construction s.r.o. between Ferrovial Construction and PORR
Owner: Zero Bypass Ltd. (Cintra, Macquarie Capital, PORR AG and Aberdeen Standard Investments) for 30 years, then it becomes the property of the SR and the NDS administration.