SR article

Cafetaria

Another possible income generating facility for the Pavilions could be a cafetaria. This article will elaborate on the design process towards 5 possible designs and a recommendation.

One of the income generating facilities that will be a part of the Pavilions is a cafeteria. This will be a place where people from the village as well as the employees of the Pavilions are able to have a seat and enjoy a meal. Since the three Pavilions that have now been build are not yet meant for the kitchen area, a temporary solution should be thought of. The chef of the cafeteria should be provided with a space to cook which protects him from sun and rain. Also a seating area for the guests should be thought of. Initially designs were made for just this temporary cafeteria. After meeting with SRI another matter was brought to the attention.  SRI will sell some of the products produced by their crop fields and carpentry workshop. Since there is no market space in the middle of Okana yet, the intention is to create one near the SRI. So the intention is to not only create a selling space for the SRI, but create an area where people from Okana  can sell their products as well.  The market stand will firstly be only manned by the person also in charge of cooking food, later, when there is more products available, there could be opted for a second seller. The second set of designs are a combination of this market stand and the cafeteria.

The aim for both designs is to suit the Pavilions both esthetically and fits the theme of sustainability and bamboo awareness. Taking these factors in consideration a design for a cafeteria and a market stand has been created. In this chapter of this report this design will be discussed. Firstly some general information on building with bamboo will be given, followed by a detailed explanation of the  first designs. After this the second set of designs is discussed. Finishing off a recommendation will be given with an estimation of the costs.

Bamboo

Over the last years building with bamboo has become more and more popular. It is a strong, durable and a sustainable material. Bamboo grows to its full size in about a year and needs about three years to obtain its high strength (Village Volunteers, 2010). Bamboo can best be harvested when the starch content is at its lowest, it will then not be infected by insects as much. This is during certain periods of the year. Un dried bamboo has the same strength as dried and treated bamboo, but is susceptible to vermin and fungus infestation.  Also, during drying bamboos shrinks up to 10 percent, which needs to be taking in account when building with un dried bamboo (Boer & Groth, 2010). Besides many chemical processes to treat bamboo, it can also be soaked in water for 4 to 12 weeks. This removes the nourishments for insects inside the poles. To be able to build a durable construction using untreated bamboo the main factor is to avoid cavities in your construction, which is where insects will huddle. Freshly cut bamboo can be bend into the desired shape and will maintain this after boiling (Village Volunteers, 2010).

Bamboo also has some restrictions. Since the fibres only grow in longitudinal direction bamboo only has its strong load bearing quality in this direction. Even though the tensile strength is higher than that of steel in this direction, no possibility has been found yet to connect bamboo in such a way that these tensile strengths can be transferred. Cross loading  therefore should be minimised (Bamboo as a building material, 2002). Looking at a roof construction the horizontal forces due to wind and flood waves should therefore been taking in consideration. An option is to use cross bracing in the structure, which ensures the horizontal forces to be taking in by the longitudinal fibres of the crossed bamboo. Also, Bamboo cannot be in contact with moisture or soil. Even treated bamboo in direct ground contact will deteriorate in 6 months to 2 years.  Bamboo protected by a stump base made by cement will last a minimum of five years longer. (Arya, 2010)

 

Cafeteria; first designs:

A temporary solution for the kitchen and cafeteria. It should shelter about 4 tables and the kitchen. When the 4th pavilion is build, this temporary shelter could be moved next to this 4th pavilion as a sheltered terrace. Also will be a place of shade until the actual tree has grown to a big enough size. 

FIrst designs2

Concept 1: Original

Creating bamboo structure and combination of papyrus and canvas roof after the original design. This will have the measurements of the 4th pavilion. The hole in the middle will end in a column/rainpipe in the middle of the pavilion. Points of interest:

  • View inside will be obstructed by the watercolumn
  • Make sure the rain goes not in the direction of the possible 4th

Concept 2: Simple derivative

Creating a bamboo structure and combination of papyrus and canvas roof after a simplified design of the fourth pavilion. Both fronts will have the asymmetric slope, but these will be in the same direction on both sides. Therefore the side roofs will just be going down in the same slope. This will ensure the rain to just glide of the roof. Points of interest:

  • Front esthetically fits the pavilions, sides won’t
  • In combination with the possible 4th pavilion will have same esthetic problems as well. Might not be that big of a problem, since it is a very open structure. And won’t be directly attached to the 4th

 

Concept 3: Roof extension

Creating a bamboo structure and combination of papyrus and canvas roof  after the wall extensions design. The two pavilions attached together are in front elongated by a wall. This concept inverts this wall and will end at the highest point of  the future 4th pavilion. The rain will just glide of the sloping roof.  Points of interest:

  • The surface area sheltered by this concept will be less.
  • When attached to the possible 4th pavilion need to be thought about a water drainage on the side.

Concept 4: Powerhouse

Creating a bamboo structure and combination of papyrus and canvas roof after the design of the powerhouse. A very slight slope (will visually be neglect able) will ensure the rain can flow of the roof.

  • Doesn’t fit the rest of the design esthetically.
  • Same height through the whole building. Might be too low.
  • Very simple/ easy to construct. Will probably be the cheapest.

 

Cafeteria and market stand

After meeting with the chairman of the SRI there has been decided to go in a different direction. The location of the cafeteria has been changed. In this case the cafeteria will be closer to the main road, which creates the possibility for it to be combined with a market stand. To minimise costs a different type of roofing has been chosen. Since at the moment quite some bamboo is left over from the construction, it would be the optimal solution to use this as the main material. The cafeteria roof will be (partly) made out of split bamboo laid next to each and its seem covered by another halved bamboo. The market stand will be covered by canvas. This to ensure it can be rolled up when weather circumstances get to rough.

Bamboo roofing

In the following designs the construction has no walls. This will reduce the horizontal forces on the construction due to wind. It does take away a part of the stability of the structure. Making sure the bamboo poles are securely anchored should give a stable enough construction. Cross bracing the corners will ensure this stability is guaranteed, but is not necessary. Since the tensile strength of bamboo in the longitudinal direction is comparable to steel, the poles will be able to carry the weight of the roof. (Bamboo as a building material, 2002). According to the research of Siopongco the bamboo roofing which has been opted for to cover the chefs area has a max overall span of 3 meters (INBAR). Therefore the construction will need an extra bamboo support in the horizontal direction. This is not needed for the canvas part.

One other aspect about building a stall with no walls is taking into account the effect of the wind. As stated in the Binar bamboo hut guideline to avoid suction and uplifting by wind the roof slope should be between 22,5 and 30 degrees, depending on the area and position of the stall (Arya, 2010). Looking at the position of our cafeteria and the climate of the Okana area, the chosen slope of 22.5 should suffice.

Lastly, since bamboo creates some restrictions in building due to the longitudinal fibers, it is important to think about the joints that should be used. Recommended for the main construction are steel tension clamps. This technique is mainly used in the construction of the pavilions. A long bolt is inserted through the upper bamboo into the cut of the vertical bamboo. A bolt goes horizontally through a lower part  the vertical bamboo through a ring at the end of the first bolt. This ensures that cross loading is carried by the bolt and not the bamboo itself. For the roofing J-bolts are advised. The bolt goes through the upper halved piece of bamboo and hooks around the framework (INBAR)

In the next part the 5 created designs will be mentioned. All five of them will need to have a foundation consisting of a concrete stump to protect the main bamboo poles from the soil.

second designs
second designs2

Design 1:

Creating bamboo structure and bamboo roof using the wall that is already there to create a separation between main road and compound. The roof slope will go downwards towards the pavilions. Points of interest:

  • Span of the roof will probably need more support.
  • Both market stand and cafeteria will be inside the compound, limiting space for both. This could be solved by having the visitors not eat under the roof. This will be a problem when the weather doesn’t allow this.
  • Since the ground inside the wall is lower than the ground outside this will create a problem when selling.

Design 2:

Creating bamboo structure and bamboo roof using the wall that is already there to create a separation between main road and compound. Inside the wall will have a roof covering enough space for the chef to cook under. Visitors will be seated outside, possible under umbrellas. Outside the wall the market stand will cover enough space for SRI to sell their products. This covered area will be covered by canvas. Since the stand is on the main road it will allow other villagers to come and join. Points of interest:

  • Canvas needs to be able to resist the rough weather Okana endures during rainy seasons and is therefore limited in its size.
  • Canvas will increase the costs, since, unlike the bamboo, it is not in possession yet.
  • Canvas needs to be cleaned regularly.
  • By having the canvas slope downwards the structure seems less open. Noted here though that most of the market stands around Okana are designed this way.

 

Design 3:

This design is mostly the same as design 3. Difference is that the market stand slopes down towards the Pavilions, creating a much more open structure. Points of interest:

  • Canvas needs to be able to resist the rough weather Okana endures during rainy seasons and is therefore limited in its size. By sloping it more outwards this limitation will be even more.
  • Canvas will increase the costs, since, unlike the bamboo, it is not in possession yet.
  • Canvas needs to be cleaned regularly.

 

Design 4:

As in the previous designs The chefs area will be covered by bamboo. In this third design the market stand will be made out of canvas. Difference is that the market stand will be retractable, which takes the limits due to heavy storm away. This retractibility is due to a scharnierend joint at the bottom. Points of interest:

  • Canvas will increase the costs, since, unlike the bamboo, it is not in possession yet.
  • Canvas needs to be cleaned regularly.
  • By having the canvas slope downwards the structure seems less open. Noted here though that most of the market stands around Okana are designed this way.
  • The market stand has to be retracted in time for a storm or heavy rainfall, also all the produce needs to be moved before it gets ruined by the rain.
  • Availability of this specific joint is scarce and a bit expensive.

Design 5:

In this last design the chefs area is also covered by the bamboo. To accommodate the visitors a retractable canvas roof is opted for on the inside of the wall. The bamboo structure is permanent, creating a kind of pergola which fits in the team of bamboo awareness. The canvas can be rolled down and hooked at the end in the same manner of a Dutch market stand. No additional umbrellas would be needed. The market stand is made in the same way as design 2. Points of interest:

  • Canvas will increase the costs, since, unlike the bamboo, it is not in possession yet.
  • Canvas needs to be cleaned regularly.
  • By having the canvas slope downwards the structure seems less open. Noted here though that most of the market stands around Okana are designed this way.
  • Canvas needs to be able to resist the rough weather Okana endures during rainy seasons and is therefore limited in its size.

 

 

Design 1

Design 2

Design 3

Design 4

Design 5

Material costs

5

3

3

3

2

Labour costs

2

3

3

3

3

Use of Bamboo

5

4

4

4

4

Complexity

2

3

3

1

2

Need for extra umbrellas

5

1

1

1

5

Open structure

1

3

4

3

3

Preparation of compound

1

3

3

3

3

Maintenance

4

2

2

2

2

Weather restrictions

4

2

1

5

4

Possibility for other markets to join

1

4

5

4

4

 Table 1 - factors

Conclusion:

In table 1 a short overview of factors is given rating them from 1 to 5 for each design. 1 being the worst option and 5 the best. Looking at this to fit both the theme of bamboo awareness as well as suit the needs of SRI the best, recommended is design 5. Mainly since this is the only design which will cover enough area without needing additional umbrellas and also has a clear division between cafeteria and market stand. Creating a structure out of bamboo which is functional as well as esthetically suits the Pavilions will hopefully show the community how versatile this material is. Having the market stand on the outside creates an open market for other community members to join. Table 2 shows a short expected cost overview of this particular design. Hopefully this cafeteria will be implemented in the future, creating more income for the Pavilions and have a market stand gathering the community.

 

Amount

Total costs (Kenyan Shilling)

Canvas

36 m2

 19800

Cement

2 bags

1400

Ballast

 5 wheel barrows

1500

Sand

 5 wheel barrows

1000

Steel tension clamps

5

 400

J-bolts

8

 400

Labour costs

2 workers 4 days

2800

Bamboo

 350 meter

0

Bolts

1 kg

300

Additional hardware

---

500 

Nails

2 kg

200

 

Total:

28300 ksh

 

Total in Euro:

256.05

 Table 2 - cost overview

Bibliography

Arya, D. A. (2010, May 25). Guideline for wind and earthquake resistant construction of bamboo huts in Bihar. Patna: Bihar state disaster management authority.

Bamboo as a building material. (2002). Opgeroepen op oktober 27, 2002, van www.bambus.com: www.bambus\new\eng\reports\buildingmaterial\buildingmaterial.html

Boer, D. d., & Groth, M. (2010). Bamboo Building Essentials The Eleven Basic Principles.

INBAR. INBAR technical report no16.

Village Volunteers. (2010). www.villagevolunteers.org. Opgeroepen op November 20, 2016