Skandinaviska Glassystem (SG) has a deserved reputation for producing unique facades using predominantly glass, steel and aluminium. In the Spring of 07 the company was asked to produce the facade for a six storey office block in Copenhagen that would present two entirely different aspects depending on the viewpoint. Viewed from the one side, the building would appear to have facade that was basically a glass wall. Viewed from the opposite side, the facade would appear to be completely finished in marble. The same effect was required for all four sides of the building - a total area of 4,000m2.
Achieving such an effect involves the use of a complex geometric arrangement. The traditional approach would have been to create a steel latticework on to which the travatin (a type of marble) stone cladding and glazing units would be attached. However, in the case of this building this was simply not feasible in terms of building loads, cost and installation time. A solution was required that would be significantly lighter than the steel latticework, would allow rapid installation and would preserve the architect’s original vision. In addition any solution would need to meet the prevailing fire regulations.
Working closely with Diab, SG has developed an innovative, modular system that makes extensive use of sandwich composites (based on Divinycell P structural core) to support both the glass and marble elements. Divinycell P was chosen because it was able to meet the structural requirements of the application and was able to pass the fire testing that was carried out at SP Fire Technology in accordance with appropriate Danish building regulations.
Once the decision was taken to adopt a lightweight composite approach, the laminates were designed. These were based on the use of Divinycell P recylable core, tri-axial e-glass reinforcements and polyester resin. The laminates were designed on the assumption that the composite elements of the modules would take all static and dynamic (wind) loads.
Finite Element Analysis
Diab Technical Service engineers carried out FEA (Finite element analysis) to evaluate the global behavior of each module and its reaction forces into the concrete.
In addition testing was undertaken at the Diab mechanical test laboratory in Laholm, Sweden to ensure that the method by which the 30 mm thick travatin cladding was attached to the sandwich composite component would meet Danish building regulations. The marble is both glued to the panel and secured with metal fittings.
Sandwich Composite Benefits
Each module is approximately 4 x 4.5 metres. As the system is significantly lighter than the traditional approach - by a factor of around 4:1 - it is well
within the permitted building loads. Taking a lightweight approach also facilitates very rapid installation by a much smaller team than would normally be the case. Further time and cost is saved by the fact that the modules can be installed directly to the steel reinforced, concrete floors of the building virtually as soon as the floors are complete and without the need for additional supporting steelwork.
Other benefits of taking the sandwich approach include the fact that the system offers inherent insulation properties, does not rust or corrode and is basically immune from moisture uptake even if the uninstalled modules are left exposed to the elements on the building site for a prolonged period of time.
To exercise complete control over of every stage of the project, SG has (again with support from Diab) set up a new dedicated production facility to manufacture the various modules using an industrialized production system based on Diab Core Infusion™.
Diab Core Kits
To facilitate the infusion process Diab is supplying SG with complete core kit sets for each module type. As the core is used as the resin transfer medium, it is first grooved and perforated to ensure rapid flow rates. Then the individual kit parts are shaped and rebated as necessary using CNC machines. The benefits of this approach is that lay-up time is significantly reduced and the actual infusion is both more predictable and repeatable resulting in a more consistent and higher quality end product. In addition, for SG there is zero core material wastage. Actual infusion time per module is 180 minutes.
As the pioneers of this concept, Diab has unrivalled experience in the manufacture of core kits. In the case of the ‘cladding’ kits, Diab was able to speed the kit manufacturing process by directly importing to its CAD/CAM systems the digital drawings produced by SG.
Once the composite elements are completed they are transported to another Skandinaviska Glassystem facility that is located close to the actual building site in Copenhagen. Here the glazing units and travatin cladding are installed. The decision to make the assembly a two stage process was deliberate in order to minimize damage to the relatively fragile travatin and to reduce transportation costs and problems (especially during winter).
Installation of the completed modules onto the building is carried by just a four person team using a specially developed, re-useable mounting fixture.
The modules were installed on the building and this process was completed in the first few months of 2009.
JEC Innovation Award
The innovatory nature of this cladding system was recognized by the JEC organization. At a special ceremony at the JEC Composites Show in Paris at the end of March 2009, SG and Diab was presented with a JEC Innovation Award.