Addition of stories Hospital region Oberaargau SRO, Langenthal

The project
With the VKF fire protection guidelines of 2015, hospital buildings in timber construction are possible. In order to meet the increased space requirements, an extension to the existing building was realized while the hospital was still in operation. In the case of hospitals, the supporting structure of the fire-section-forming components must meet 60 minutes of fire resistance in encapsulated construction (R60-RF1 or EI60-RF1). This high requirement is prescribed in normal office and residential buildings only for the vertical escape route. The load transfer of the addition to the existing building fabric was only possible at a few defined points. This results in large spans for the timber construction and correspondingly large beam deformations.

The construction
The addition is a skeleton building structure in timber construction. Vertical loads could only be transferred selectively and at specific locations into the existing solid building structure. In the roof, the spans of 7.7 meters were bridged with a partially insulated box girder. An underslung beam bridges an inner courtyard with a span of 16 meters.

The challenge
Forming the fire compartments while accommodating the large deformations of the girders and the sliding connections was a major challenge. A specially designed connection of the interior walls to the roof allows the roof elements to deform without transferring loads to the walls. The fire protection authorities approved this special construction with an "approval in individual cases". Another challenge is the high installation density that is common in a hospital.