Tropical developing economies are some of the most vulnerable societies to natural disasters and by 2050, some 50% of the world’s population will live in the tropics. Over one quarter of the urban population of South East Asian tropical developing economies reside in non-adequate housing. The UN Sustainable Development Goal 11 (SDG11), targets by 2030 the access for all to adequate, safe and affordable housing, and suggests that the building of sustainable and resilient buildings utilising local materials should be a catalyst for development. Cement production is the third-largest source of anthropogenic emissions of CO2 and could rise by 23% by 2050 given current trends. Sand for construction is also being un-sustainably sourced which in the coming decades will affect the concrete supply chain. We need to look at new sustainable, locally available natural materials for construction, and architects will need to respond to this challenge and develop new processes to work with natural materials which ensure structural integrity and affordability. Tropical developing economies are large producers of bamboo, a material with good tensile and compressive properties and a low carbon footprint when sourced locally. Bamboo can be worked with simple tools and can be grown locally on a village scale or even a family scale. Bamboo can also absorb CO2 and stabilise slopes to tackle the effects of deforestation.
If we are to increase the use of renewable materials, then we should look to non- or marginally-engineered building materials to ensure that the most affordable form of bamboo, ‘full culm bamboo’, (also named ‘round bamboo’) is used. Bamboo will degrade in a structure if not designed or built correctly. Exposure to UV light and moisture can bleach, crack and encourage fungal growth causing structural and aesthetic damage which impacts greatly the perception of bamboo in the mind of potential end users, reinforcing a notion of bamboo as temporary, or the ‘poor man’s timber’.
Computational design tools allow the architect to visualise ideas and they can be modified and analysed interactively, though this modification can still be time consuming. Generative design software allows us to build on this process and specify relationships among parameters and instantly output versions or iterations of a design. This is algorithmic modelling in which we design an algorithm to take a set of input parameters to generate a defined output of a design which responds to our needs.
As suggested by Willis and Woodward in 2005, it may be impossible to achieve a direct correlation between digital data and a constructed building. Some design parameters like material flaws, grain directions and inconsistent densities will be difficult to anticipate in modelling software. However, this gap between the building and the model will continue to narrow.
We will use the tactility of bamboo material and physical models to explore the properties of bamboo at scale. In the computer we will generate, test and refine our designs with the bamboo material considerations of buildability and durability. Using generative design tools we will push our designs for full-culm bamboo as far as possible in the computer establishing how far digital design tools can and should be used when designing for full-culm bamboo.
The structural system we are looking at in this course is one of a planar truss which is developed from a catenary arch and will be constructed using bolted joints. The choice to use a planar truss is one of buildability and construction site safety. A planar truss can be built flat on the ground and rotated into place in the building. This is done by laying out all the bamboo poles cut to size with the correct cut type on the ground and bolting them together before lifting this up into place in the structure. The adoption of bolted joints, which are used previously in timber constructions, leads the extensive utilization of bamboo to bigger construction than those with traditional joints. With these modern connection systems, it is possible to connect many bamboo poles at once to create a bunch of poles as large columns, high beams or multilayer frames to serve wider span or higher structures. The characteristics of these connections brings forth a specific bamboo architecture with a specific aesthetic appearance.
Although we will design and work with bolted joints, a vast array of the possibilities of joining bamboo will be presented during the workshop, based on the classification of bamboo joint by Andry Widyowijatnoko (2012). An example of lashing based, high tensile strength bamboo joint is called bamboo radial compression joint (barcom joint) with multiknots. This and other type of joints can be proposed in the projects developed in this workshop.
If we can develop greater syntheses between the digital and naturally variable, as designers we can obtain tools which can increase the use of renewable natural materials with variability such as bamboo, and begin to propose new applications for sustainable natural materials.
At the end of the course one design could potentially be built in the Summer of 2021 in Bandung, Indonesia.
Background text and images are taken from the published work of the course directors:
Widyowijatnoko, Andry, (2012), Traditional and Innovative Joints in Bamboo Construction.
Naylor, John Osmond (2020) The Opportunities and Challenges of Using Parametric Architectural Design Tools to Design with Full-Culm Bamboo.