PROJECT DESCRIPTION:
The Nato High School design seeks to remedy the perpetual cycle of destruction and reconstruction by streamlining construction methods through prefabrication. The system proposed is primarily a steel braced frame structure comprised of a kit of parts that is manufactured within the controlled environment of the workshop. The modular system is easily transportable as all parts can be shipped via container and assembled on site with minimum construction knowledge.
All components are derived from standard, readily available and easily produced structural steel shapes ranging from angle irons, steel tubes and structural tees. The roofing members are a bow truss system comprised of steel angles that can be shipped pre-assembled. Attachment of members is a combination of bolt-on and welded systems.
After erection of the main structure, finish materials are comprised of locally available materials. For the Nato High School, Philippine mahogany and Narra wood are used for their beauty, durability and resistance to pests. The use of these woods occur in the sliding storm panels and interior ceiling finishes of the classroom buildings.
The modular, prefabricated quality of the design benefits the school in many ways. Buildings can easily be expanded or reconfigured as program needs change. Construction is simple and straightforward, and minimizes waste while efficiently using material during its production within the shop. This, combined with its use of readily available materials, makes for an elegant yet robust construction system.
Strength and Durability
Since strategies of heavy, brittle construction have failed to stand up against typhoons in the past, we have taken the opposite approach in using a material that is light and strong. Like a bamboo reed that bends in the wind, the structure is designed to flex but not break in the presence of extreme lateral forces. The tensile qualities of steel allow the design to achieve this “bend but not break” concept.
The proposal uses two redundant systems to resist lateral movement. The first is a series of infill shear panels of wood stud and sheathing construction. The second is a series of diagonal tension braces. By working together, damage from high wind speeds and earthquakes is minimized. The more structurally transparent areas of fenestration and access are protected by heavy “storm” doors which slide over and shield these openings from extreme winds and driving rain. The storm doors also help to secure the buildings during hours of non-operation.
Uplift and overturning forces are resisted by hold down connections as well as a unique design feature. The profile and angle of the shed roof have been designed similar to an inverted airplane wing, or airfoil, to create down force on the building as high speed winds pass over them.
Sustainable Site and Building Design
The site is organized along a skewed grid system. East-west grid lines are spaced 3 meters to echo the modular dimensions of the classroom buildings. North-south lines are oriented towards the prevailing wind to promote cross-ventilation throughout the site. Landscaped areas hold indigenous ground cover plants, while hardscaped areas are of a permeable surface such as grasscrete and porous concrete to minimize flooding levels and increase surface water filtration.
The buildings have been designed around the concept of the “Ocean Breeze Filter”; filtering screens of louvers at either side of each building promote natural cooling through cross-ventilation, allowing for nearby shore breezes to “filter” through the building during humid days. Operable intake vents at the base of walls also allow low, cool air to infiltrate and force hot air out of the building through elevated vents on the south facades. Large southern overhangs shield interior spaces from direct solar gain, yet still allow reflected daylight to naturally illuminate the classrooms. Building orientation is set to maximize exposure to the northeasterly prevailing wind and minimize harsh western exposure to the sun.
The roof design utilizes high R-value rigid insulation, while its sloped design sheds water during rains and collects them into cisterns for landscape use during the dry months. The wood elements of the building are from local, renewable sources, which can range from narra to bamboo. The steel elements can be re-used at the end of the buildings life-cycle, as well as originate from recycled sources. The durability and strength of the steel structure will ensure an extended life span.
