Bamboo Architecture for Sustainable Communities Andrea Fitrianto Architecture Sans Frontières Indonesia andrea@asf.or.id
Abstract Bamboo architecture offers some answers to the 21st century challenge that lies in realms of ecology and the social. In introducing bamboo architecture to communities, attention shall be given towards a more holistic way in capitalizing local resources; that is including materials, technologies, required knowledge and skill-sets, and the social capital. Bamboo as fast growing giant grass distinct itself from trees. The difference in structural characteristics and properties between the two is also known. This paper argues for particular appropriate technologies with bamboo, which emphasize practicality and effectiveness in using available resources within the community. That is through working with round bamboo with bugs resistance treatment, with steel bolt joinery, and community participation throughout all project stages, from planning to design, to construction. In doing so, it will raise strong ownership to the build structure, and ultimately contributes to the long term goals of sustainability. Examples and illustrations drawn from author’s experience in planning and development of community projects using bamboo i.e. a pedestrian bridge in Davao, Philippines, community centers in Yogyakarta, and an alternative school in Bogor, Indonesia. Key Words: bamboo, sustainability, participation, urban
Bamboo in the 21st Century The discourse on global warming, climate change, and sustainability, which has been around for the last few years, is not going anywhere but here to stay. It has crosses disciplinary boundaries and it enters architectural discourse too. Through its capacity to capture carbodioxide and to produce biomass, bamboo provides some preliminary answers to the global challenge. Although, how big or significant bamboo may take role in sinking carbon from the atmosphere is still debatable (Liese, 2009; Lobovikov et al., 2009). Nonetheless, this has been the point of departure of bamboo into contemporary architecture (Meinhold, 2010). Vitruvius believes that architecture requires strength, beauty, and functionality. Bamboo has been providing these three basic ingredients of architecture to communities and cultures since the time immemorial; bamboo is versatile and being use to make baskets, flutes, fans, partition walls, carriages, bridges, etc. Nevertheless, along the course of modernization and the intensified use of information technologies bamboo has been left behind; as the poor man’s timber. But now, even the rich and the inspired adores bamboo and put bamboo for their favourite tropical villas and off-grid cocoons (Meinhold, 2014). So far, the phenomenon has been correctly addressed by the architecture academia. There‟s an urge in rediscovering bamboo when we see students flock bamboo seminars, courses and workshops (Irwantoro, 2014). And there is an increase of academic publication on bamboo which takes architectural perspective. In light with this, few things matter in how to go through the re-learning curve of bamboo, what kind of bamboo attitude we needed to develop. Bend, but do not break. Be like a bamboo!
2 perhaps is the phrase which carries the wisdom of flexibility that is needed when dealing with constraints, academic boundaries, mental fixations, social conformity, etc. Yet, we shall not exclude local community which has been keeping bamboo groves, maintaining practical know-how that often amazes us (Soeprayitno et al., 1988). Local communities pass indigenous knowledge from generation to generation to make these available for us to date.
The Elements of Construction There is a striking commonality among some twelve-hundreds identified species of bamboo (Lobovikov et al., 2007). Though vary in size, bamboo culms consist of around 60% parenchyma cells, 40% fibers, and whereas 10% is vessels (Liese, 1992). The fibers, which is appear densely at the outer skin of a bamboo culm, accounts for culm‟s load bearing capacity. While the parenchyma tissue which holds the fibers together reacts as a “shock absorber.” Transversal section of a culm shows unique characteristic of bamboo, that is distinct from wood. This has been inspiring numerous research in engineering, on standardizing test methods, and eventually to exploit bamboo‟s remarkable strength (Janssen, 1988, 2000), thus bamboo joinery development shall tally with. The ultimate challenge in working with round bamboo is that connection design is tricky due to the natural shape of a culm; it is tapering, it is hollow, it is hard outside but softer inside, and finally, the relative distance between the joint and the node has to be considered.
Choice of Joinery Through centuries of building traditions, such as practiced in Southeast Asia, bamboo joinery relies much on the use of dowels and rope lashing (Dunkelberg, 1985). But, since 1980s researchers have been trying to modernize bamboo joints by incorporating steel bolt, gusset plate, wood and mortar fill in connections (Mishra, 1988; Morisco and Mardjono, 1995; 2003), even using steel cord for a particular way of lashing (Widyowijatnoko and Trautz, 2012). When proven for effectiveness and safety, further challenge to these experimentations is how to make the newly invented joint affordable and available for public use, thus may contributes to greater good. In regard with this, bolts and mortar fills gain more popularity. Placed either in perpendicular or in parallel to the grain, bolts are being used in connections, to transfer load between bamboo poles. In presence of bolts or metal rods, sand-cement mortar filled into the bamboo cavity, thus when it completely cured, it can transfer load between the bolt(s) and the internal surface. The strength of this method perhaps lies in its practicality; in the appropriate use of common materials and from the widely available tools it needs.
Picture 1. Communty volunteers preparing hook bolts during Davao bridge project.
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Andrea Fitrianto Bamboo Architecture for Sustainable Communities
Among practicalities of steel bolt is that it can be prepared using threaded bar that is sell in local market in length of 1 or 3 meter. There are three types of threaded bar commonly found; the bluish high-tensile stainless steel, the dark-colored iron bar and light-colored galvanised iron threaded bar. The first has superior performance, but the latter has just appropriate performance while still affordable. Threaded bar is cut to the lenght needed, or to bend the bar‟s end to make a hook bolt. All can be done at the project site. As a rule of thumb, the ideal size of the bolt is one-tenth of the size of the bamboo. That is, 10 mm bolt to connect bamboo poles of 10 cm in diameter, 6 mm bolt to connect poles of 6 cm, and so on. Proportion matters since bolts require drilled holes which removes bamboo fibers. Also mind the thickness of bamboo, or the wall, it has to be thicker than the bolts, thus the wall shall not be easily sliced by the bolt. The following are projects that was primarily use of steel bolts. Moreover, compressive joints were emphasized to ensure design effectiveness, structural integrity, and eventually, the safety of the community level infrastructure.
Pedestrian Bridge in Davao The bamboo footbridge in Matina community, Davao, Philippines is a community infrastructure project financed by a loan and built through bayanihan mutual help (Fitrianto, 2013) that was driven by the urgency of need (Alperovich, 2013b). In use since June 2011, the project was showcased in a government‟s publication on “best practices” in climate change adaptation (Claudio, 2012). Soon after its completing, a flash flood which take place on midnight 27 June 2011 drowned the bridge by one meter deep at the center post. Flood debris batter the trusses, thankfully seamless mold of reinforced concrete between the 10 cm thick platform and the foundations hold the bridge. Entering its fifth year in use, it is safe to say that the borate preservation of the bamboo, using vertical soak diffusion method, works satisfactorily. While, another aspect of the bridge that is worth a discussion is on the topics of bamboo design and joinery.
Picture 2. Community-built bamboo bridge in Davao, Philippines.
Arch is the most classical approach to bridge design that is also applies to modern bamboo bridges, such as those designed by renowned architect Simón Vélez and builder Jörg Stamm. Natural bend of bamboo gives precedent to structural design. Arch offers a minimum risk of Parahyangan Catholic University| 3 Bandung, West Java Indonesia, July 31, 2015
2 transversal torsion, or buckling effect, in case of asymetric load. In truss design, Howe truss system practically provides construction height as base for roofing. Morevover, it allows simpler joinery design as tension and compressive structural members interconnect and neutralizes each other (Stamm, 2009).
Picture 3. Joinery designs and analysis from Davao bridge project.
The complete recipee for a long-lasting, permanent bamboo structure is applied in Davao bridge project i.e. (1) provision of concrete foundation which keep the bamboo away from ground humidity (2) sufficient roof pitch and adequate eaves overhangs which protect the bamboo away from rainwater, and finally, (3) the bridgeâ€&#x;s existence relies on social infrastructure, that is the community guardiance. The bridge is guarded 24x7, is lit by night, and there is fee collection of one peso per passenger. This have had been providing fund to pay minimum maintenance expenses such as thatch replacement and renewed protective coating which was done last year. In an ordinary day, there is approximately 500 passengers pass the bridge.
Community Centers in Yogyakarta When some community members of Kampung Pakuncen in Yogyakarta came to consult for building a community center, the only available site within the kampung was the air space above the drainage channel which splits this river bank settlement (Alperovich, 2013a). Aware of the technical constrain, it was thought that the centre shall be built with concrete beams and a concrete slab. But, even to cover a merely 5,5 meter gap, concrete structure would cost much beyond affordability of the community. So, the community decided to use bamboo for the project. They took a loan from a local savings and community self-help organization called Kalijawi. In fact, the Kampung Pakuncen leaders were inspired by their peers in Kampung Jatimulyo, another riverbank community which is located upstream in Winongo river.
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Andrea Fitrianto Bamboo Architecture for Sustainable Communities
Bamboo is not strange to people of Yogyakarta. There is a thriving market for few kinds of native bamboo that is including pring apus (Gigantochloa apus), pring petung (Dendrocalamus asper), pring wulung (G. atroviolacea), and pring legi (G. atter). However, the common use for market bamboos are for temporary constructions and scaffoldings. Thus, the poles are often too young and weak and its resistance to bugs (Dinoderus minutus) is not assured.
Picture 4. Compressive joints with steel-bolts and mortar fill (left, middle), power drill (right), used by community volunteers in building the Kampung Pakuncen community center in Yogyakarta.
In Kampung Pakuncen some community members volunteer in the project were construction workers. So, it was advisable to use available skills and labor in the project, but need to outsource treated bamboo that can prolong the lifetime of the strucuture. A local company Bambubos offer poles of apus, wulung, and petung at affordable price. This collaboration, help reduce development cost down to USD 2.500 and ensure sustainability of the community center. Until now the Pakuncen community center serves multi-functionally, from hosting meetings to tiedying workshops, from hosting wedding ceremonies to funeral wakes.
Picture 5. The community center in Kampung Jatimulyo, Yogyakarta done through gotong-royong mutual help.
Alternative School in Bogor In city of Bogor, a group of young parents strive to build and run a primary school which taught principles of ecology and Islam. The school project was intended as an alternative to the existing schools in the city which suffers by common problems of overcrowding amidst hard Parahyangan Catholic University| 5 Bandung, West Java Indonesia, July 31, 2015
2 environment of “concrete jungle.” In late 2012 the group began the project and decided to build the school with bamboo (Arkom Indonesia, 2013). Cost effectiveness and pupils‟ safety was among the main criteria. When the project was completed in early 2013 and obtained around 300 m2 effective floor area, the project costs around USD 45.000.
Picture 6. Alternative school has to be affordable and safe: elliptic plan increases structural integrity
The school was built on elliptical plan with row of columns separated in 5 meter distance. Each column complex host a range of bamboo poles vary in length and inclination, thus create undulating roof ridge. The composition of bamboo columns gave a unique overall look in which, according to a student, resembling a dinosaur. Roof slope is maintained between 45-60o to ensure free flow of rainwater in a climate with prolonged wet season. The synclastic roof configuration creates form-active surfaces which enhances structural stability and integrity (Maurina et al., 2014). Indeed, the choice for natural roof cover of daun nipah (Nypa fruticans) requires replacement after 3-4 years of use. After a year in operation the school administrator were looking for financing posibilities to support school‟s expansion and they propose the building as bank collateral. However, the local bank refuse to accept it and excuses that the school building is unconventional and nonpermanent, therefore is not worth as a loan collateral. In this case, the choice of building materials have excluded the school from the available financing system. But, perhaps this is a reminder for bamboo promoters, builders, and enthusiasts to be self-sufficient and always strive for local resources including when it came to budget and project financing.
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Andrea Fitrianto Bamboo Architecture for Sustainable Communities
Discussion As shown in the case of Davao bridge, community centers in Yogyakarta, and the school in Bogor, bamboo architecture provides solution to community‟s immediate needs. These real needs were nuanced by the imperatives of necessity and of urgency. In the case wih the urban poor, scarcity had been brought for long by inequality and lack of social justice, as seen in the case of the bridge project in Davao and community centers in Yogyakarta. In Bogor, the bamboo school gives hope to a community of growing middle class in demand for quality education which entails particular kind of built environment; a school made of bamboo. Through the examples given, bamboo projects serve as platforms for participation and allow community members to gather, plan, design, and construct together. This is evident in the pedestrian bridge project and the community centers. The available space for participation is influenced by the technology and method being uses; the use of round bamboo and steel bolt connection. Community participation sow local ownership (Fitrianto, 2014) and eventually promote sense of place. Both are essential components of sustainability through place-making. The centers in Yogyakarta contribute in building social capital at community level and beyond (Hersh, 2013; Kamil, 2014). Furthermore in sustainability, the dimension of time remains a variable. How long we expect a building to serve? And among other long-lasting questions, is bamboo an ultimate answer to the great challenge of humanity i.e. to turn to another and live in harmony with nature, or is it merely some kind of exotic ritual of pseudo-naturalism to satisfy our unquenchable thirst in consuming statuses and symbols? As the wind blows, we shall not expect answers from the wailing bamboo, nor from the twisting groves which signify a coming typhoon. We shall bend but not break.
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