BMW - acoustic centre Aschheim

Case Study

The design of the new acoustic centre of the BMW Group was a tremendous engineering challenge. RIB's software solution ensures transparency of planning costs from start to finish

Spectacular projects are nothing unusual for the engineering company Lenzer + Strutz in Gauting near Munich. Nevertheless, the team under the project management of Harald Schreiber, Markus Siegl and Daniela Rajczy have excelled themselves with the design of the new Acoustic Centre of the BMW Group at the company’s Aschheim site. Except for the structural engineering, technical outfitting and electrical design, they performed all the tasks involved in the complex design process besides acting as general planners. “None of us have ever been confronted with such challenges in our career before,” reminisces Markus Siegl, responsible for Construction Phase 1 of the airborne sound reduction laboratories in Aschheim.

Automotive at its Best

The result is certainly impressive: The model plant for the automobile industry opened by the BMW Group on July 23rd is the only one of its kind in the world. Working to the owner’s specifications and after complex simulation calculations of Müller-BBM GmbH, the Munich engineers designed a completely new exterior noise test stand and window and ceiling test stands, which in variable combinations of reverberation chambers and free-field rooms create new possibilities for further complex acoustic measurement techniques and detailed analysis. “The icing on the cake” for all manufacturers in the automotive industry all over the world, as the engineers from Lenzer + Strutz tend to call it. This does not only describe the result itself, however. Thanks to their excellent cooperation, the companies on both the planning and the building side have done excellent work in mastering the unusual and therefore particularly difficult design and construction specifications.

High-Tech meets innovative design

The overall project was divided into three sub-projects, each led by one of the three project managers. Harald Schreiber was responsible for the acoustic roller test stand, which was built on the site of a former car park. “As exterior noise measurement  in Aschheim used to be done outdoors on the test track and was therefore dependent on the weather and susceptible to ambient noise interference, our client decided to build a new building 34 metres long, 22.5 metres wide and 7 metres high,” explains Schreiber. These dimensions are given by a defined measurement cycle. Exact and true-to-reality measurements can only be taken by the BMW Group’s measurement and simulation software when the microphones are 7.50 metres away from the axis of the vehicle. “The room was additionally fitted with  1,80 metre-deep acoustic wedge lining", the project manager continues. The result is a fully anechoic chamber that enables a large number of further sound measurements to be taken. The Gauting design engineers also gave the world’s largest acoustic roller test stand a new façade: Combining architectural features typical of the rest of the site and modern design, the exterior immediately gives an indication of the state-of-the-art technology inside.

Excellent design performance

The space created in the acoustic centre by building the new test stand was used to accommodate modern airborne noise reduction laboratories; in fact, the most revolutionary known to the automobile industry to date. The construction work in the already existing building was divided into two sections, which were headed by Markus Siegl and Daniela Rajczy, respectively. “The design engineers had particularly complex acoustic specifications to consider,” reports project manager Rajczy. In order to interconnect all the test stand rooms it was necessary to build an extension to the building. It was also important to ensure that each individual room was acoustically isolated. We made about 70-80 detailed drawings,” the project manager recapitulates, “particularly because we had to keep adapting to new specifications in the design phase. The same applied to the construction companies, such as Guggenberger who were responsible for masonry construction, or Krapf GmbH who did the dry lining including the necessary underlying steel construction.” Concerning the test laboratories, the Bavarian designers had the job of building them room-in-room as well as fitting floating floor boards and “skew” walls. This creates a fully homogeneous sound field, by means of a “sound mixing chamber”, as it were: no wall may be parallel to another. Grünzweig und Hartmann GmbH were commissioned to produce a completely new type of sound-absorbing insulation element for the test stand rooms. These prototypes were developed in cooperation with the specialists from Müller-BBM.

End-to-end project lifecycle management

As the engineering company Lenzer + Strutz covers the entire scope of work of the HOAI (official scale of fees for services by architects and engineers) in its own company, it benefits from the full project management facilities of its software. Supported by RIB’s system solution for project controllers, RIB Construction Suite, all those involved in the project work on a decentral data master. Project information is transferred and processed throughout all phases. This way, risks can be safely contained and planning costs remain transparent from start to finish. From cost estimating through cost calculating, from compilation of the work specifications to billing. “The bidder tool Offerte-L is ideal for cooperating with our subcontractors,” explains Markus Siegl. “We purchased the software components once and can now provide them free of charge to all subcontractors we work with on a project. The quotations can then be re-entered into the software solution really easily via  GAEB-XML.“ Using the RIB software solution, it’s easy to exchange data with the BMW Group, too, namely via RPA format.  

For projects of such dimensions, it is essential to keep cost risks to a minimum throughout, as the three project managers all agree. The engineers at Lenzer + Strutz have already been able to rely on RIB software in numerous complex projects all around the globe, although they are particularly proud of the “icing on the cake“ in Aschheim.

Photos: BMW Group

Industries>Architecture, Engineering & Construction>Developers>Lenzer + Strutz

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