80-Ton Load, Zero Tolerance: How Thomas Linder Designed Radiation Shield Using RFEM

Project Description and Geometric Design

Constructed in the West Neutron Beam Hall of the Heinz Maier-Leibnitz Research Neutron Source (FRM II), the radiation shielding structure “LaDiff” was designed to enclose the entire experimental area and safely shield radiation emissions. The structure is intended to allow for experiments with neutrons in a controlled environment.

The enclosure has a trapezoidal floor plan measuring approximately 10.0 m x 6.5 m, with no obstructive interior columns. On the diagonal side, the slab features a semicircular opening for material transport into the experimental room, which is supported by a ring beam resting on two columns. From there, radially arranged ceiling beams with variable cross-section depths distribute outward.

Technical Challenges and Digital Design

To ensure maximum radiation protection, the entire structure was covered with 5 cm thick lead cladding mounted on 10 mm thick stainless steel plates. Managing the resulting 80-ton load of the cladding while strictly adhering to minimal deformation tolerances was a key challenge for the team. It was also necessary to construct the entire substructure from a special, non-magnetic stainless steel.

To solve this problem, the engineers used comprehensive 3D building models in RFEM as early as the preliminary design phase to obtain reliable foundation loads for the highly indeterminate structural system. During the design phase, every member of the specialized frame, including the stability analyses, was precisely calculated. The seamless integration of the workspace and printout reports ensured that every adjustment was immediately documented in a way that was transparent to the structural engineer.

It builds trust when, as an engineer, you can verify all the design checks and the program isn't a black box.

Using the Steel Design add-on, I was able to easily design the members made of this specific material, including the stability analyses. Not every program can do that—most are limited to standard steels.

Thomas Linder TuB Tragwerk GmbH

Why Dlubal Software?

For Thomas Linder and his team, Dlubal Software is the top choice for projects ranging from simple structural systems to highly complex 3D models. The software consistently impresses with:

• Maximum multi-purpose capability: Suitable for everything from multi-story buildings to specialized scientific structures or renovations in timber structures, where nonlinear hinges account for slippage in dowel connections.

• Integrated efficiency: Free features, such as the wind and snow load generators, save valuable time during structural load introduction.

• Reliability & clarity: Highly efficient structural analysis, backed by responsive support, gives engineers confidence in their results at all times.