GARS-NEPAL.TIBET Earthquake Emergency
Retropolis is a modular wooden primary structure system for community re-construction. The wooden elements consist of simple glue-lam pillars and beams with wooden joints and CLT (cross-laminated timber) plates. The structure can work as independent houses, or as being combined for communities in different size.
The modular system provides adjustable individual shelters for family units and collective kitchens, sanitary units and community gardens. Special containers will be used for rain water collection, composting of organic waste and sludge treatment. The environmental technology units are developed together with the VTT Technical Research Centre of Finland.
The cost-effective / cheap glue-lam and CLT is produced as an industrial side-product of the more commercial CLT production. The material is not as “beautiful” and finished as the normal commercial CLT, but it has equal structural capability. The primary structure has high earthquake performance and fire-resistance. The roof structure is out of 2/4” LVL (laminated veneer lumber) with corrugated steel sheet roofing. All the wood material is PEFC certified ecological timber. The elements can be assembled together and dissembled without any special tools.
Cross-laminated timber (CLT) is a sheet-structured, multi-functional, structural timber product. CLT is produced by gluing structural timber into layers, each layer perpendicular to the previous one. Structural CLT most often uses spruce or pine. As a construction material, CLT most closely resembles traditional precast concrete. CLT is an especially viable option in load-bearing structures as well as floors thanks to its versatility and characteristic strength properties.
CLT structures are proven to be extremely earthquake resistant in several locations. CLT provides cheap structural overcapacity compared to other building materials. Under limit-state conditions, CLT exhibits ductile failure mechanism. In other words, CLT is capable to carry loads, even if it is damaged. This property translates in safe structures in which accident loads do not cause escalating failures. All wooden elements of the Retropolis primary structure contribute to the lateral resistance, providing structural safety and redundancy. Connections for CLT are extremely simple. This also results in quick construction times compared to concrete.
Standard 60 cm diameter concrete drums are used for foundation. The wooden structure is lifted above the ground in order to let the rain and storm waters run freely under the Retropolis. The uplifted structure also helps to prevent from snakes and insects.
The interior corridors which are leading into the courtyards in front of the collective kitchens act as wind chimneys which will ventilate the Retropolis community structure bio-climatically.
All building parts are designed to fit effectively into standard 20/40 ft. sea containers. Wood is light-weight in terms of transportation and can be chopper-lifted to the site in case needed.
The secondary structures, such as dividing walls and facades are made out of local materials and recycled construction waste.
1. On the fast shelter use the primary structure can divided and glad into private units by temporary materials, such as:
· tent canvas
2. On the upgraded use the primary structure can be divided and glad with local materials and recycled and semi-temporary materials, such as:
· stone baskets with recycled construction waste
· sand bags with recycled construction waste or sand if available
· weak concrete: soil mixed with cement, construction waste and straw
· recycled bricks
· local stones, mud bricks
è The primary structure will in effect take care of all the structural load and earthquake performance. The secondary structure is not considered to have any structural value.
Author: Casagrande Laboratory, Finland
Representative of Author: Marco Casagrande, Architect
Construction Engineer: Timber Bross Ltd., Finland
Materials: Glue-lam pillar 18x18 cm
CLT panel 60 mm
LVL structural wood 2/4″
Corrugated steel roofing panel
Concrete drum D=60 cm
Environmental technology: VTT Technical Research Centre of Finland