Maximum results in a minimal space.

Works: Bridge of composite Steel and Concrete Structure

Location: Pörstental, Germany

Project features: this work followed the demolition of the previous bridge on the A9 Berlin-Nuremberg motorway. ALPI designed a carriage for the construction of the reinforced concrete deck on the structural member of steel. The shaped formwork and bracing of the ALPI carriage were designed using MECCANO components, while the main structure of the full-plate primary girder TAP 2500 acted at the same time as tracks for its movement. The formwork used for the wings was hung directly from the carriage. The structure was assembled on site following the indications by the contractor, with constant assistance from an ALPI specialist who followed all the phases, including the structure movement. The formwork was raised using a mobile crane, and was advanced along saddles welded to the steel structure fitted with special rollers. The side could be opened to allow it to be moved without the need for disassembly and reassembly. The "drawer" formwork units for the central part, propped for casting, also slid along brackets placed inside the steel structure with sliding guides. The whole structure was built for a total of six casts, each 16 m, to guarantee rapid execution of the works. The total width of the carriage equalled that of the works, 18 m. As the bridge stood alongside another bridge, a further difficulty overcome by ALPI was the design of a formwork opening mechanism with maximum functionality while working in a very small space.