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| Autobahn in Essen get's new ceiling and walls A 1,500-m long road tunnel under downtown Essen, Germany, needed to have its walls and ceilings refurbished. A job in which time was of the essence, which had to be completed within a timeframe of two weeks. And it was, thanks to the smooth and successful interaction of a team of specialists from ThyssenKrupp Xervon's building preservation unit. Over 140,000 motor vehicles pass daily through the two tubes of this tunnel built in 1970. The tunnel is the city section of Germany's renowned A40 that passes through the Ruhr region at speeds, originally intended to be fast, but now mostly snailpace. So it was not surprising that the contract awarder (North Rhine-Westphalia's Roadworks department, Krefeld branch for motorways) wanted to limit the working time to a few days in order to keep as short as possible the necessary shutoff time and hence the daily traffic chaos. Within this tight time schedule, 25,000 m² of concrete walls and ceiling as well as 20,000 m² of wall tiles were in need of professional refurbishment. Additional jobs included minor structural steel and sealing work. For these jobs, the timescale of a mere week was available for each of the tunnel tubes. During these few days, first of all the concrete wall and ceiling surfaces were closely "tapped" in order to detect any damage. Crumbling concrete was dislodged, cracks were marked, hollow sections prized apart. Meter-wise the concrete refurbishers on their mobile platforms proceeded through the tunnel sections. The next step: dry sandblasting of the exposed surfaces so that the accessible reinforcing bars could be freed from rust (cleaning standard SA 2.5) and then given an initial corrosion-protection coating. In two shifts, the maintenance men worked on the tunnel, with up to 14 employed per shift. write your comments about the article :: © 2009 Construction News :: home page |