Technical Challenges of Large Movable Scaffolding Systems

Abstract The method of construction of decks of bridges and viaducts with several spans using movable scaffolding systems (MSS) is very efficient and competitive. This solution is generally used for the 40 to 60 m span range. Over the last few years, new experiences have been acquired and new solutions have been developed for the 70 to 90 m range (large MSS or LMSS). In this range, unexpected economical results may be achieved if the number of spans is high and/or if the costs of piers and foundations are relatively high. With LMSS it is possible to achieve very high productivity ratios. The application of LMSS implies significant technical challenges. Some are similar to the more common MSS, but others become more relevant. This paper discusses bridge–equipment interaction including main vertical loads on the bridge, horizontal forces on piers, wind actions, wind-induced vibrations on piers with MSS stabilization, accidental MSS-induced actions, thermally induced horizontal displacements, and deflection control. Two real examples are presented. The design criteria recommendations are listed in the conclusion section.