05/05 week07

REFLECTIONS

Today was spent finishing off the final model. The title of the proposal was called OPENSOURCEBAMBOOLEGO. The reason behind this name was that one of the key ideas behind the proposal was that there would be a range of basic fixings that people could use to put a bamboo structure together in whatever way they can imagine, just like a set of lego blocks. The system would also be so that anyone could create new parts to add to the system, just like an Open Source computer software.

The joints of the model were made from from timber. This was done initially as timber seemed to be the easiest material to shape and manipulate. However there were some challenges in making the joints etc. Timber required that the parts fitted together perfectly for maximum strength and this meant that the joints took quite a while to make. This type of intricacy is not ideal as it will likely make the joints quite expensive and easily damaged.

A steel alternative was made with the spare time. It was found that the steel version was structurally equally as stable as the timber version and yet much more tolerant of inaccuracies. The challenge with steel was the need to weld whenever there was a need to put different angles together. This could potentially limit the ability of the users to make and change the fixings themselves.

REFLECTIONS ON PRESENTATION

One of concerns raised during the presentation was that the joints appeared to be quite intricate and costly. Whereas the economic and social context of East Timor and the site of the project was quite poor. This difference was something that needed addressing.

There is certainly a need to simplify joints further. The time and difficulty in making the joints out of timber at the workshops is a good indication of the likely cost of a full scale mock up of the joints. Perhaps the steel alternative version of the joints is more suitable. Another option is perhaps just providing jigs or templates to create the joints. This way the transportation requirements and capital cost of the system could be reduced even further.

Another student explored an interlocking system of timber joints. This might also be a worthwhile direction of development as it would eliminate all requirements of mechanical fixings and make the structure even more robust.

04/05 week06

STRUCTURE CLADDING

Thoughts now turned to how to clad the structure. How would floor plates and exterior/interior walls be fixed to the structure? And how would these be operable?

For this, glass fixing details were analysed to see how things might be done. Glass is often fixed after a basic supporting structure is in place and this could be useful for purposes of this East Timor project. In many instances, the glass is secured without any cuts or holes. This is a useful thing for the assembly and disassembly of the cladding as it makes things simple. Some of these systems are also very useful in that the fixings act not only to support the panels in place but also lock them in place.

The operability of the structure’s cladding was also examined. How might windows and walls be incorporated? Louvre type systems seem to be the most effective and adaptable out of these.

There are also some interesting instance of overlapping panels into grooves to create a facade. Potential here to create an interlocking system for the facade.

There have also been examples of using inter slotting panels to create a self supporting structure. However, the size of the panels can create issues for handling and transportation. Thus such a proposal would not be suitable for large scale structures.

TRANSPORTATION and DISTRIBUTION

The way the structure would be distributed is an important part of this project. The focus of the project is very much on the design of the joints to utilise East Timor’s local bamboo and not require any transportation of large structural components. In effect, the only thing that would be supplied would be the joints and instructions. The rest, the structural members, floor plates, walls etc. will all be sourced locally. This would mean that shipping requirements are minimal.

This not only saves money and resources for transportation, but also allows the structure’s crucial parts to be transported to remote locations. This also opens the possibility of the proposed structure to provide emergency accommodation etc.

It would also be possible to set up the structure as a kind of “open-source” system, where everyone and anyone can create new joints based on the existing system. And it might also be possible to setup online trading of different joints and online ordering of custom joint manufacture etc.

It would be interesting to see how the units of these structures would be distributed all around the world. The joints would of course be able to work with steel members and timber members as well. The cladding and panels that create the building envelope would differ in nature and insulation properties according to their location. For example, a structure in Canada might use quite thick insulated panels, whist a structure in India might use timber screens.

03/05 week05

BAMBOO STRUCTURES

Today was spent in the workshop working towards suitable joint for use with bamboo.

The work of Shigeru Ban was also investigated. Ban’s work with cardboard tubes was particularly interesting as cardboard tubes are very similar to bamboo posts in that they are both cylindrical.

Ban’s structures are all assembled from cylindrical members of cardboard tubes.  The articulation and joints could all potentially be adapted for use with bamboo. Ban’s structures also explore the physical possibilities with such assembled structures. He explores not just basic orthogonal structures but also arches, composite arches and portal frames. As a lot of Ban’s work is to do with emergency shelters, they act as highly suitable precedent studies for this particular East Timor project.

Arches seem to be very interesting as a structure as they allow large floor areas to be roofed very efficiently with minimal material. Composite truss arches are also quite effective, offering superior stiffness to a simple arch. The incorporation of tensile wires between truss elements adds even more to strength of the structures.

After studying the examples, physical models were made to study the characteristics of such structures. The physical models were made using bamboo skewers and joints were created with hot glue. The bamboo skewers offered a reasonably similar material to actual bamboo posts. The skewers consisted of vertical fibres, just like bamboo posts. The skewers also offered a certain amount of flex, which is also just like natural bamboo.

02/05 week04

METAL/STEEL

Today was spent in the workshop going through steel/metal working techniques etc.

• METAL ADVANTAGES

Steel is a very appealing in that it is strong in both compression and tension and that is has a high strength to weight ratio (strength to weight ratio is a material’s strength divided by its density, the higher the ratio, the more strength per unit of weight). Steel has a ratio of 254 kNm/kg compared to a timber such as Oak that has a ratio of 87 kNm/kg (source: http://en.wikipedia.org/wiki/Specific_strength).

Steel is quite a robust material, reasonably resistant to environmental conditions and also to wear and tear.

Steel also offers greater flexibility than timber, both in terms of material strength properties as well as joining techniques. Many structures that would not be possible in timber can be done in steel.

• METAL DISADVANTAGES

The disadvantages of steel are that it is not as easy to work with as timber. The most effective way to cut/shape steel is to use mechanical means, such as saws, drills and grinders. Whilst manual means such as hacksaws etc. are also possible, these can be very time consuming, especially when dealing with large structural members.

The fixing of steel is commonly done by bolts, welding, rivets etc. Out of these riveting and welding are permanent joints and are not suitable for disassembly. Bolts would be the preferred method. Welding would also require specific welding machinery that might not be available in remote East Timor conditions.

Below are some diagrams of standard steel/metal joints:

Steel, whilst being a comparatively lightweight material, it would still be impractical to expect to assemble a structure entirely out of steel members. Such a structure and each of its members would still be very heavy and difficult to move around. Thus for a structure that is designed to be assembled and disassembled, such a solution would not be suitable.

BAMBOO

More research has also been conducted into the use of bamboo as construction material.

Traditionally, there have been many examples of buildings and structures that have been constructed out of bamboo, so there is nothing particularly special or unique about the use of this material. The traditional way of working with bamboo has been to use ropes etc. to secure elements together. Although this method is highly effective, it requires skilled craftsman who have the skill. It is also time consuming and not easily disassembled.

Below are some examples and links of traditional bamboo fixing techniques

bamboo construction guidelines

In recent years, there has also been a lot of interest from architects etc. towards the use of bamboo as a potential construction material and many have investigated projects involving bamboo. Notable architects include Simon Velez, Renzo Piano, Shoei Yoh etc. Below is a link to some modern examples of projects that involved bamboo: modern bamboo architecture.

Out of these, Simon Velez’s projects seem to be on the largest and most elaborate scale and he seems to have the most experience with the material. However Velez depends on his own group of carpenters and builders who are very experienced with working with bamboo. The fixing method that is used also seems to be primarily with permanent nails and screw etc. Not easily taken apart. This is not suited to the particular requirements of this project.

Piano and Yoh’s work are most interesting in that the joining methods employed appear to be able to be easily disassembled. These could be very useful precedents for this particular project in East Timor.

SCAFFOLDING

A rather interesting subject that has come up as a result of the investigations into bamboo structures. Bamboo scaffolding has always been a very important part of the construction industry in Asian countries. It has been known to be stronger and better than its steel counterpart. The flexibility in the bamboo members allows the scaffolding to flex and counteract the destructive forces of earthquakes and cyclones. Bamboo scaffolding is in fact fixed with wound ropes, just like in traditional bamboo construction. Whilst this is not particularly suited to this East Timor project, it has brought to attention the value of scaffolding as a quick, secure structure that can be easily transported, assembled and disassembled. Steel scaffolding works by using steel tubes as a basic component and assembling them together into large structures with a range of fixing components.

Therefore, further research was conducted into scaffolding components and how they work.

Scaffolding steel tubes hold a certain degree of similarity to that of bamboo posts. They hold similar physical properties in terms of strength, compression and tension characteristics. They are also similar in shape, in that both are cylindrical. Is there the possibility of using steel scaffolding fixing components to assemble bamboo members?

Some physical modelling was done to test this idea. Some discarded scaffolding parts were found and experiments were made to test whether it was actually possible to fix bamboo elements together with scaffolding components. Unfortunately, it was difficult to find bamboo elements of a large enough size, as such PVC tubes were used as a substitute. The experiment was quite successful. The joint was quite strong and there was also a small amount of adjustment possible to account for differing bamboo post sizes. The use of scaffolding components would mean that it would be possible to source a primary structural material (bamboo) locally and minimise transportation needs. And only transport the fixing components required for the structure.

REFLECTIONS

to use bamboo feasibly in this project, a quick and simple assembly/disassembly method is required. Traditional techniques are very time consuming and require expert knowledge.

precedents of Piano and Yoh’s projects and also of scaffolding components suggest possible joints that would allow simple assembly of parts together by anyone

such a joint system would also save a great deal of transportation as most of the structural elements could be sourced locally and only the fixing parts would be shipped to the site.

bamboo is vulnerable to deterioration over time, although this is not a big problem for the use of bamboo as it is a very cheap and readily available, whatever structural system is proposed will need to be able to replace structural elements easily.

it is also realised that all of the joints considered so far have required a kind of “sequential” assembly and disassembly, in that the structure could only be put together in a certain order. This reduces the flexibility of the structure and also can create a lot of problems for maintenance. An example of the problems that could result can be seen in the Nakagin Capsule Tower by Kisho Kurokawa, where the apartment capsules have to be unloaded in a certain order, so that to replace ones at the bottom would require all those above to be removed. This challenge will need to be resolved.

01/05 week03

TIMBER/WOOD

Today was spent in the workshop going through woodworking techniques, common joints, standard connector fixings etc.

• TIMBER ADVANTAGES

Timber appears to be a material thats easily worked. To shape the material, all that is required is really just a saw and some very basic carpentry skills. The joining of separate timber members together is a little more complex and requires a good knowledge of proven timber joints and how the material will expand and shrink with different environmental conditions. Although there are limitations as to how timber components can be assembled together, there are many fixing components/mechanisms readily available to allow difficult assemblies.

• TIMBER DISADVANTAGES

However, there are also many disadvantages to timber. Timber is quite a heavy material, especially when members need to support heavy load, large loads will require some quite large timber members. This characteristic will certainly limit the ability of individuals and small groups of people to erect large scale structures. It will also require that transportation and lifting equipment such as cranes, trucks etc. will need to be employed. In the context of the potential project in East Timor, the need for such equipment could pose a challenge. The mass and size of the timber that might be required could also pose significant challenges for transportation. It does not seem very realistic if the entire construction is prefab and every single component needs to be transported to the site in East Timor.

Timber is also assembled in traditional constructional with nails, screws and glue etc. These ways of fixing are permanent. Fixing components will have to be used if the structure is to be assembled and disassembled.

BAMBOO

A material that is similar to timber is bamboo. Bamboo also happens to be abundant in East Timor. Bamboo is very strong and very light. However there are limitations and challenges to working with bamboo. Bamboo must be carefully treated to ensure that it will stand up to the weather and insects. Bamboo is a difficult material to shape, the cylindrical post shape  is not the easiest profile to work with. As bamboo is a totally natural material, there are also natural distortions.

Below is a link to some basic information on the characteristics of bamboo.

bamboo basic information

REFLECTIONS

1. minimising transportation requirements is a challenge
2. minimising use of heavy mechanical lifting, moving equipment is also a challenge
3. more research could be done on bamboo as a construction material
4. there could be potential to integrate the use of bamboo with other materials such as timber, steel and glass