Close to Münchner Freiheit in the Schwabing district, the state capital is planning the general overhaul and expansion of the Oskar-von-Miller-Gymnasium and the Maximiliansgymnasium. Both were built before World War I and share a horseshoe-shaped building complex. After the Second World War, the venerable school building had to be rebuilt and comprehensively renovated at the end of the 1970s.

Building in historical ambience

While preserving the historical building fabric, the technical building equipment and the entire static load-bearing system of the listed existing building will be renewed over the next four years. The challenges include the replacement of ceilings, the installation of a new roof construction and the strengthening of the foundation by underpinning. In addition, the inner courtyard will be put to maximum use by installing an underground gymnasium and an extension building as a specialist class wing.

Photo: Michael Stibitz

Complex shoring works

As technical leader in Arge, the Max Bögl Group was commissioned with extensive special civil engineering, drainage and earthworks. The main trades are jet grouting and large bored pile work. A back-anchored excavation pit with bracing base in the former gymnasium is being constructed by means of jet blasting for the new construction of an underground ventilation centre. This technology will also be used to underpin the strip foundations of the building wings and the head structures of both grammar schools. The new gymnasium and extension buildings will be constructed in excavation pits surrounded by simply back-anchored, overlapping pile walls. The existing groundwater levels, in conjunction with the depth of the gymnasium, require a lift protection with micropiles and a lowering of the groundwater level.

Three-layer excavation pit

Progressive explosive ordnance soundings, additional temporary steel girder structures with wood infill, low-pressure injection work and various steel girder frames are to be integrated into the work process. The special civil engineering works are supplemented by the excavation of the three-layer subsoil from filling, quaternary gravel as well as tertiary clays/slides and sands. After thorough analysis, the excavated material is sent to a qualified, proven disposal facility. The construction period for the complex remediation work extends from September 2018 to November 2020 - with a core construction period between October 2018 and May 2020.