Bamboo has been part of life of Mixia people. The villagers have been using the material in the construction of houses, fences, water channels and even for the existing bridge. Our vision is to integrate this fascinating renewable resource further into the people’s life and hence bamboo will be used in most of the structural components of the new bridge.
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QWERTY Design Team
Wu Zhi Qiao Bridge Design Competition
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DESIGN CONCEPT
•Our team has adopted a scheme of bamboo arch with suspended deck. Inspired by the swaying of bamboos during breeze, the single arch will have their two supports on different sides of the deck. This is to mimic the ability of bamboos to sway in all directions of its longitudinal axis. •Bridge deck is to be supported by two main longitudinal beams. Each beam is made of two bamboos poles tied together to increase the beam shear and bending capacities. Structural robes (nylon or organic) that can be found from the nearby town are used to tie the main deck to the arch. Bamboo cross beams and bamboo mat (interlaced bamboo strips) will complete the decking. •Steel shoes of nine-hole slot will be used to support the bamboo arch. The base plate will be bolted to competent volcanic rock on the river banks. The span of the bridge deck will be increased to 22m to ensure that an allowance of about 1m from the river bank is achievable for the base plates.
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SUSTAINABILITY
•Locally available materials are used for the bridge. bridge Steel shoes for the arch are the only component that required special technology from contractor. However, this is a one-off assignment. Also, the shoes are not heavy and can be carried manually. Installation requires a small drilling machine that can be easily transported to the site by villagers. villagers •Skills that exist amongst villagers (tying, splitting bamboos) are required for the bridge construction. •Treated bamboo can last for about 10 years. To ensure this, 10mm-diamter holes will be introduced at the bottoms of the slots to channel any rain water away. This is to ensure that all components of the arch are dry throughout the year and hence decomposition will not take place. •The deck is above 4.5m above river bed. This is the ensure the deck will not be washed away even when river water level reaches its maximum. •With the new bridge, transportation of goods, cattle for agricultural work and better access to the market and healthcare will improve the livelihood of the villagers. villagers
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BAMBOO TREATMENT
•As bamboo is susceptible to pest attack, treatment is required. Fresh bamboo will be submerged in water for about 6 weeks. The river can be a good option for the purpose as treatment in stagnant water tends to create foul smell and effectively pollute the water body. The immersion is to remove bamboo nourishment that is attractive to insects. •The bamboo is then air-dried for another 6 weeks before being used for the construction.
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Construction Method