New Marazzi High School – a school building entirely made of wood

Glued Laminated Timber, LVL, School buildings, XLAM

Assignment of commission

Fornale Engineering was contacted by the public administration in the early design stages of the Institute. The decision to involve us was certainly successful. The structural schemes were defined based on both the need for spatial flexibility and the requirements of building services. We chose to use only wood and wood-derived materials for this new building; the structural scheme was designed by optimizing the different materials available: LVL, CLT and GLT.

Building description

The building consists of 3 distinct sections: the school building itself, the multipurpose gymnasium and a laboratory section. The school is developed over a total floor area of 6,000 m² on 2 floors. A CLT bracing system with non-seismic-resistant LVL frames was designed. The floors are made of CLT panels on GLT beams. The gymnasium is developed over an area of approximately 1,800 m² with a maximum height of approximately 10 m. There are glulam timber trusses with a 36 m span. The laboratory section is developed over a total of 1,800 m² on two floors. In this case as well, a seismic-resistant system with CLT walls, LVL frames and CLT floors on glulam beams was chosen.

Structural scheme

The building was designed using a “heavy” frame in glulam timber and Baubuche LVL wood. The seismic bracing system was entrusted to CLT cross-laminated timber shear walls. The main structural grid has variable dimensions with a minimum width of 6.5 m and a maximum of 9 m in the laboratories. CLT cross-laminated timber floors with spans of 6.5 or 9 m were designed depending on the case. Having frequencies below 8 Hz, specific analyses were conducted on the floors for vibration verification purposes. Particular attention was given to the robustness analysis for the verification of “disproportional effects”; the building is in Consequence Class CC2b. The building was calculated to have an R60 fire resistance rating.