Bauer soon finishes specialist foundation engineering work for the KARL business complex

In the heart of Munich district Maxvorstadt and right by the studio of Bayerischer Rundfunk, Bavaria's public broadcasting service, a new office complex is being built on the former premises of car dealership and service company Münchner Automobilhandel und Service GmbH (Mahag). The new business quarter known simply as KARL was designed by leading British architect David Chipperfield, whose most famous works include the Neue Museum in Berlin, among others. The 7,500 m2 site is to have a two-level underground car park, a green rooftop terrace, a restaurant, offices, and a courtyard that will be accessible to the public and created by famous Swiss landscape architect Enzo Enea (find out more about the project at www.karl-muenchen.de).

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As part of the project, BAUER Spezialtiefbau GmbH was commissioned by the client KARL München GmbH & Co. KG to carry out a range of specialist foundation engineering works for building a deep excavation wall anchored in multiple layers. To this end, 380 individual replacement bores reaching a maximum depth of 10 m were firstly drilled using a BAUER BG 30. Here a total of approximately 2,000 drilled meters were backfilled. To lower and regulate the groundwater, a dewatering system was installed in the form of wells. During the works, old sheet pile walls and steel girders were also found and these had to be removed as an additional measure.

Construction of the roughly 4,200 m2 Mixed-in-Place wall could then be started. This task involves using an RG 25 S as a drilling rig and an RG 16 as a vibratory rig to produce the MIP elements with a diameter of 550 mm and down to a depth of 15 m. Due to the high loads to be exerted by planned subsequent building development, the MIP wall is being secured with up to four anchor layers using the twin rotary drive method. Overall, approximately 4,500 m of anchors are being built with the aid of a KLEMM KR 806-2 DK, where the length of the anchors will range between 15 and 21 m and the number of strands will vary between four and seven. Bauer is also creating a sheet pile wall anchored in one layer to act as a supporting structure for the ramp area. The main works are expected to be completed in December 2018.