Background of current methodology and its limitations in the design and application of curtain walls, worldwide.
Current curtain wall systems in mid and high rise buildings have serious limitations that result to damages during natural disasters (earthquakes & hurricanes). Being rigidly connected to the structural skeleton of the buildings, they become structural elements and follow the same deformations of the main structure of the building, unable to take large deformations during earthquakes, blasts and hurricanes.
“ALUSTET” – A Breakthrough Innovation
“ALUSTET” is an innovative concept unitized curtain wall system that revolutionizes the construction and structural behaviour of building envelopes when installed on to middle and high rise buildings.
“ALUSTET” curtain wall system is a passive energy dissipating system that protects building envelopes against major shocks due to earthquakes and hurricanes and makes the building envelope resilient.
“ALUSTET” concept engineering solutions focus towards the most economic costs, safety of human lives and properties, energy, water and material savings, healthy indoor air environment and improved operational efficiencies.
The main concept of the ALUSTET system, following a very different design approach than the prevailing standard practice of the industry is to separate the curtain wall of each floor from those of adjacent floors, in such a way, so that the displacement of the one storey to be independent from the others.
ALUSTET system is designed to allow excessive displacements under earthquake and wind loads well beyond the existing worldwide building code requirements, it is airtight and water impermeable and has achieved the highest of scores in several international Laboratory tests and curtain wall mock up tests of various building projects.
Specifically the ALUSTET system:
- is capable of resisting 20% higher forces than Katrina hurricane/typhoon , based on full – scale laboratory tests according to ASCE standards.
- can withstand all recorded California earthquakes, based on full- scale laboratory tests, according to UBC 97 standards. See Earthquake laboratory Test
- exceeds the US Government blast requirements, based on a finite elements analysis
The system has become the best functional and economic choice for complex double curvature facades and those requiring 3D curved & segmented unitized panels.
ALUSTET system due to its excellent earthquake and wind resistance properties has set new standards in the application of curtain walls sector worldwide.
However, in addition to its excellent structural behaviour and technological superiority to existing systems, the advantages of the new concept are numerous:
- Projected (operable) windows can be continuous along the entire perimeter of the building.
- Architectural freedom. To the area of the windows there are no mullions, and thus the width of the vision panels can be as wide as the architect wants. The same possibility exists for the spandrel area (glass, stone, aluminum, composite panels etc).
- The fixed parts (spandrels) can be made of any cladding material, like granite, marble, aluminum composite panels, wood and metal panels, etc.
- The floating part of the curtain wall can extend from floor to ceiling, if so desired.
- External shades can be installed on cantilever supports fixed on the studs and coming out through the vertical joints of adjacent panels.
- The ALUSTET system is modular (unitized panels), can be manufactured off-site and the various units can be easily replaced during the life of the building.
- ALUSTET system is not face sealed.
- All vision fixed panels can be converted at any time easily to projected windows.
- The installation of the curtain wall panels takes place from the interior of each floor, thus it is more cost effective and not affected from any weather conditions. The use of scaffolding during erection can be diminished or even eliminated.
- The installation may be conducted at any location of the building, independently in different floors (great advantage for replacing old facades – recladding – without disturbance to the occupants of the building).
No need of any sequential procedure.
- Fire proofing between the slab and the fixed part of the curtain wall system is much better performing than conventional systems and thus provides protection against interior fire spread to adjacent floors.
- The glass panels are not bonded directly on the mullions of the structure of curtain wall.
- Water tightness and air tightness are achieved without using silicones.
- ALUSTET system is capable of resisting wind pressures corresponding to hurricane category extreme 5 (ASCE 7) and blasting pressures according to US Ministry of Defense Codes.
- Each glass unit or cladding panel can be removed without removing adjacent glass units or cladding panels.
- Cabling can be installed horizontally through cavities along the horizontal beams (lintel or sill) and then run vertically.
- Provides better indoor environmental conditions (all windows can be projected)
- The concept of ALUSTET system allows construction of functional and safe compact double skin facades for the energy efficient building envelopes of the so called GREEN BUILDINGS
- The concept of ALUSTET System is ideal for rehabilitation projects i.e. replacement of existing facades without interrupting the operation of the building.
In few words the ALUSTET system is competitive in terms of safety, quality and cost.