An innovative method of sustainable wooden modular construction has been selected for the building of 32 schools in Berlin by 2025
6 of these schools have already been constructed and the rest will shortly be underway. One of the schools is made up of almost 100 modules, each 3-m wide and 8-m long.
All of the modules have been prefabricated offsite and assembled on the construction site. Construction is under The Senate Department for Urban Development & Housing and Metsä Wood’s Kerto® LVL beams have been used.
The decision was made by the structural designers to use beams made of the high-performance and easy-to-process GLVL (Glued laminated veneer lumber).
To achieve a column-free floor plan for classrooms, 8-m long lightweight high-performance GLVL beams had to be used at the joint of the modules.
Sebastian Hagspiel, project manager at Kaufmann Bausysteme elucidates: “For structural reasons, glulam was not suitable for this project. Steel beams were also not a solution for us or the architects.”
Wooden modular construction: fast and economical
Berlin is keen to become the world’s major metropolis for wooden modular construction or at least one of them. Right now, three-storey wooden schools are being built in Berlin by Austrian prefabrication constructor Kaufmann Bausysteme (KBS).
“6 schools have already been built and a total of 32 schools are to be built by 2025. The speed of the offsite construction method was a decisive factor. With the prefabricated wooden modules, the construction time can be halved” explains Hagspiel.
‘LVL is stronger in strength-to-weight ratio than steel’
The GLVL was manufactured by Holzwerke Bullinger using Metsä Wood’s Kerto LVL.
Ingo Faller from Bullinger’s sales department describes the process as efficient: “We have updated our standard glulam process so that we can use LVL beams. The GLVL beams have a high bending strength.
“In the GLVL process, laminated veneer lumber (LVL) beams are glued together. Compared to glulam, LVL is uniform in quality and therefore has an extremely high static load-bearing capacity.
“As a result, GLVL beams have a much higher flexural strength. Interestingly, LVL is stronger in strength-to-weight ratio than steel.”