By David Reed, UT EditorBerlin- Elastogran GmbH's sandwich plate system (SPS)-steel sheets sandwiching a thick layer of polyurethane elastomer-has found another civil engineering application: reinstating an ailing section of Berlin's underground railway system.In just four weeks, a 100-year-old bridge on the over-ground Schönhauser Allee section of the city's U2 railway was renovated using the SPS technology, without any disruption to the service. This avoided the need to provide a replacement bus service, a significant cost which would also have increased congestion in the fast-changing city, a statement from Elastogran indicated.London-based Intelligent Engineering, ThyssenKrupp Stahlbau from Duisburg, Germany, and Elastogran collaborated on the pilot project, which aimed to demonstrate the superiority of the new technology. Experts from Aachen's Technical University (RWTH) monitored the project throughout, in order to provide an overall evaluation of the performance and trial data.Following normal preparatory work including grit-blasting, testing of the surfaces and repair of cracks, the steel construction work began. Holes were drilled in the cross girders, drainage tubes were sealed off and, finally, new prefabricated steel plates were attached, forming a new underside of the structure. The cavity between the existing bridge deck and new steel plate was then filled with about 25 kg of PU elastomers per square metre and, as soon as the material had cured, new drainage holes were drilled. After a final lick of paint, everything looked as good as new, Elastogran said.Other bridge projects are in planning, among them being a motorway bridge in Germany, the firm added."