Thursday 29 October 2015

Week 11: Rhinoceros Session

First Session

Basic setting up, keying commands and playing around with forms.

Second Session

Building modal from plans.

Week 9: The Lure of the Continuous Skin

Case studies from OCEAN Design Research with a research area regarding Auxiliary Architecture.

What is Auxiliary Architecture?
Auxiliary Architecture is a kind of material system used to improve an existing situation. An example of a situation which redefined the fence and reduced it to merely embrace the building design; creating a less hostile atmosphere to the surrounding. It also organizes spaces and modulate micro-climatic environments that has already build up contexts in which it is not possible to modify or replace the urban fabric building.
The system is more akin to tree canopies; a differentiated array of membrane patches; construction of additional compression elements, frames or anchor points. Nets were developed as continuous or branching systems; triangular patches in hexagonal arrays.
Auxiliary Architecture is a supplementary to permanent domestic structures. In hot climates, it often provides essential shade, either as stand-alone shelter or as transitional spaces between the cool interior and sun-exposed exterior. It is a history that offers great potential for innovative sustainable solution that require little or no energy.

Projects from OCEAN Design Research
M-Envelope

Steel mesh provides three primary criteria for the M-velope. It provides the self-supporting structures, it also sets out the spatial divisions through the twisted ruled surface logic and finally through the materiality of the mesh a provision of screened conditions initiates a porous visual gradient between interior and exterior conditions.
The membranes further articulate and accentuate the spatial divisions and visual conditions set out by the logic of the steel mesh as a gradient spatial.
Consequently Auxiliary Architecture can provide an integrated approach to architectural design and sustainability. The Auxiliary Architectures research area focuses on performance-oriented research by design, the development of versatile design solutions as well as related design methods that integrate analogue form-finding with advance computational design methods.

Research Question
To what extent can we still talk about a creative process when large and crucial parts of the output are generated by a machine? Can we still claim to be designers when out level of control is reduced?

Week 10: The Scientific Vernacular (final)

To what extend bamboo is used as a façade treatment in tropical and subtropical climate?

Introduction

Bamboo constructions are well known in various countries in Asia and South America. Several famous architects; for example, Vo Trong Nghia from Vietnam and Kengo Kuma from Japan; have explored the potential of bamboo to get inspired in their designs. They apply the inherent properties of the plant in their works based in tropical and subtropical (warm) climate. Bamboo is used in a refined architectural way in terms of façade treatment or building structure where sunlight is filtered by bamboo as sunshades and privacy is kept without preventing daylight to enter. According to Kengo Kuma; he explained the vertical bamboo poles of the façade seem to give a soft, airy feeling to the overall structure. The bamboo façade screens in the spaces to invite visitor in a pleasing and delicacy manner thus creates a design that stands in between Japanese and Western approaches (Figure 1).

Figure 1: Kengo Kuma's bamboo house

Bamboo Facade

The major feature of bamboo as a façade treatment is the fact that it is open to daylight and air; as a screen wall (Figure 2). The gap between each bamboo poles are very well ventilated; thus the rays of sunlight entering through the facade look nice but do not result in overheating the house. Bamboo facade is one of the important components of a building. Not only does it give an identity to a building but it also plays the vital role of acting as an interface between the interior space and the exterior. However, another factor that affects interior and exterior comfort of the bamboo building is the climate issue; for instance the solar heat or solar radiation, temperature, wind flows, rainfall and humidity. As a consequence, the façade and climate determine how a person feels about a building from the outside as well as a whole living experience within a building.

Figure 2: Bamboo as screen wall

Construction of bamboo facade

Bamboo screen walls are extremely durable and long lasting. It can also be used in multiple climates as the bamboo is resistant to rain, excessive heat and ultraviolet rays. It has excellent environmental benefits as bamboo reduces pollution by absorbing carbon dioxide and other toxic gases. Having a comparison between trees and bamboo; trees are allowed to be used once when it is being cut down whereas bamboo is allowed to be used repeatedly as the grass grows back after being harvested. The construction of bamboo screen wall is completed in multiple ways. The most popular method uses a row of bamboo poles to tie them together with twine. In a warm climate conditions, the walls can even be constructed as an ecological growing wall. Making the bamboo screen wall is not easy due to its uneven characters on the material. The craftsmen have to be very precise about the thickness of the base and the spacing of the poles. The one way of constructing the bamboo screen wall will be placing the bamboo poles horizontally between columns. In some part of the wall, bamboos are placed side by side with appropriate joinery creating a full bamboo façade on the external face.

Environmental Performance of bamboo facade

Tropical and subtropical climate has an average temperature and relative humidity between 30-33ᵒC and 70-86% per month. The primary concerns of the tropical and subtropical climate in the warm humid region are high temperature and humidity. To overcome it, the main strategies are to provide maximum ventilation and shading to avoid heat storage. Bamboo screen wall provides a unique screen that protects the building from intense sun. It is able to reduce the sunlight intensity by 10% compared to a reading that is gained in an open space under the daylight. The windows and bamboo screen walls are well insulated that allows heat to egress from the building through the gaps between the poles as the wind flows through the building. It also acts as a heat recovery ventilator and provides fresh air into the building. Besides that, the bamboo screen wall reduces the temperature differences between the exterior and the interior of a bamboo facade building by 4-5 degrees throughout the day and night. The differences between indoor and outdoor temperature decreases because heat evaporates as it starts to transmit internally into the bamboo pole.

The bamboo screen wall design proves that thermal comfort throughout the year by improving air movement within the building. High rate of natural ventilation will lead to a situation where the indoor humidity levels follow the outdoor condition. The gap between the bamboo screen walls manage to achieve a ventilation rate that is more than required by the standards, hence this criteria has been addressed adequately. Continuous air flow within the room should help achieve a reasonably good quality of air.

Conclusion

Bamboo as a local material, is known as a bioclimatic design because the properties of the bamboo response towards the local climate. The main objective of bioclimatic design is to provide ‘comfortable’ living conditions with a minimum reliance of artificial energy. It is obvious that keeping the building warm in the cold season and keeping the building cool in the hot season is the main design objective for comfortable buildings for tropical and subtropical climate conditions. In conclusion, bamboo; as an alternative building material has both economic and ecological advantages in comparison to concrete and steel constructions; thus provide aesthetic and thermal comfort to the users.

Week 8: The Scientific Vernacular (progress)

How does bamboo perform thermally and aesthetically as screen walls in various climatic locations?

Introduction

There are several famous architects who explored the potential of bamboo and get inspired in their designs to apply the inherent properties of this plant in their work. We can see how bamboo structure can produce various forms and aesthetics. Moreover, bamboo has a greater tensile strength than steel. Therefore it can be easily bent. The rising concern of bamboo about rapidly depleting resources is fuelling a bamboo revolution of sorts as this simple species of grass is being used. Some architects were aware of the finite resources of our planet and devoted to invent sustainable buildings and transportation for the people. Some was driven by the simplicity and extraordinary strength of bamboo as a building component. Since bamboo is a sustainable and quickly renewable resource, it then involves in construction projects with pioneered new designs and construction methods for buildings of all kinds. Some examples are Green School in Bali and Kayu Manis Resto in Bali.

The façade is one of the important components of a building. Not only does it give an identity to a building but it also plays the vital role of acting as an interface between the interior space and the exterior (shown in Figure 1). However, another factor that affects interior and exterior comfort is the climate. The climate relates to solar heat or solar radiation, temperature, wind flows, rainfall, humidity and topography. In the climate issue, temperature is the most important thing to be considered, this is because temperature mostly refers to comfort which is influenced by other climate factors. This paper uses bamboo as the constant façade material to experiment its performances in various climatic conditions. These are all crucial in ensuring the well-being of the users of the building. The façade and climate therefore determine how someone feels about a building from the outside as well as a whole living experience within a building.

Bali Bamboo Wall

Bali region has tropical climate with 2 seasons, rainy and dry season. The highest intensity of solar radiation is up to 502W/m²; the temperature is up to 33ᵒC and the average relative humidity is between 70-86% per month. Since Bali is located near the Equator, it means that daylight hours are consistently 12 hours. The primary concerns of the tropical climate in the warm humid region are high temperature and humidity. It will need several strategies to prevent negative impacts and to take full benefits from the climate’s positive impacts. The main strategies are to provide maximum ventilation and shading to avoid heat storage.

Tropical climates are hot and humid. Therefore keeping the heat of the sun off is the top priority. Bamboo-structure building provides a unique screen that protects the building from intense sun and provides a veranda. The windows and prefabricated walls are so well insulated that the home’s primary sources of heat are the occupants and the sun and a heat recovery ventilator provides fresh air. The temperature difference between the exterior and the interior of a bamboo-structure building averages 4-5 degrees on a hot summer day.

Bangladesh Bamboo Wall

Bangladesh has a subtropical monsoon climate characterized by wide seasonal variations in rainfall, high temperatures of 36ᵒC and humidity between 63-83%.

Typically bamboo houses have bamboo mat walls with bamboo posts. Flood with strong currents can destroy wall panels, get washed away and may be partially or complete lost, especially if the connections to posts are weak. Adequate number and size of perforated bamboo mat walls should be built orient along the prevailing wind flow direction to allow cross ventilation. Currently, the field study of Bangladesh traditional bamboo houses are done on several number of bamboo houses at rural and suburban areas in Bangladesh. For environmental study, temperature and humidity data are taken by thermal data logger (HOBO). The initial finding of the thermal performance study of the traditional Bangladesh bamboo house is comfortable at night in hot summer season. The maximum indoor temperature is recorded 29.5ᵒC when outdoor temperature is 29.95ᵒC. Indoor minimum temperature was recorded 26.6ᵒC when outdoor temperature is 27.12ᵒC. The indoor temperature is always lower than outdoor space. The difference between indoor and outdoor temperature decrease because of heat starts to transmit from hot spaces to cool indoor living spaces. According to this phenomenon from the tabulation, it is indicated that it has sufficient difference between indoor and outdoor temperatures.

Yunnan Bamboo Wall

The climate of Yunnan Province is warm, rainy and humid. The annual average temperature is 21ᵒC. The average temperature is comfortable so there is no strong demand for thermal and protection from heat. The main concern is to avoid the humid ground. The Dai area in Yunnan has an abundant rainfall amount which means the moisture on the ground level of a ordinary house is relatively higher than the other areas in China. Bamboo buildings have much lighter weight than the traditional and typical brick structured buildings in North China. Bamboo in Yunnan has a large productivity among local plants and the growing speed and productivity is much more considerable than timber. To be advance, the wall of stilts houses are covered by weaved bamboo strips. The gaps between the strips make it possible to let wind blow into the indoor space, which can be considered as a pattern of passive ventilation. Since bamboo has a strong adaptability to different climate, it is believed that bamboo as a material itself would not be easily changed in physical quality. Also, the Dai area of Yunnan is close to the edge of tropical area and locates in the arm and flat rural area in mountain district, so that bamboo as a main building material is excellent in consider of strength and budget reason.

Chennai, India Bamboo Wall

Chennai is located on the South-Eastern coast of India and is the capital city of the state of Tamil Nadu. The weather in Chennai is hot and humid for most part of the year. Extreme variation in seasonal temperature is prevented due to its location on the thermal equator and the proximity to the coast. The temperatures during the day is between 35-40ᵒC and around 20-32ᵒC during the nights. The relative humidity is high throughout the year with values higher than 80% during the nights and early hours of the day. During the day, the relative humidity is around 40-60%. According to studies carried out in India, the limits of thermal comfort is said to vary considerably. The thermal comfort of a person is said to lie between 25-30ᵒC with optimum 27.5ᵒC. The bamboo design proves that thermal comfort for a large part of the year can be achieved by improved air movement within the building. High rate of natural ventilation will lead to a situation where the indoor humidity levels follow the outdoor condition. Relative humidity was not considered in the current study as literature study shows that high humidity, especially in hot-humid climate will not affect thermal comfort as the users will be accustomed to it. The bamboo design manages to achieve a ventilation rate that is more than required by the standards, hence this criteria has been addressed adequately. Continuous air flow within the room should help achieve a reasonably good quality of air.

Western Europe Bamboo Wall

The environmental performance of bamboo used in Western Europe highly depends on the form in which it is used. In its natural form (the culm), in several applications, bamboo process more than 20 times as sustainable as the common western building materials timber, steel and concrete. When used as an industrial product such as wall panel; the environmental advantages of the bamboo culm are lost. Compared to most wood-based alternatives, the environmental performance of the assessed bamboo panel is slightly less favourable. Nevertheless, with some adjustments in the production process, a non-bleached sustainable alternative of the bamboo panel is possible. Furthermore, by applying a bamboo panel, technical problems related to the geometry of the culm can be avoided. Still, when choosing bamboo for its sustainability, it is recommended that the culm should be used.

Practical problems when using the bamboo culm in Western Europe are numerous and have a couple of bamboo-related main sources: the shape of the material, the irregularity of the material and the lack of knowledge and building codes. Many of these problems can be avoided through centralisation of knowledge and development of bamboo building codes. Therefore, many problems in future bamboo projects in the West can be avoided, thus saving time and money while upgrading the quality of these projects. Bamboo is a natural product with irregular shape. It is therefore suggested to be used in temporary buildings or play a role as a finishing material.

Conclusion

This vernacular architecture has grown out of simpler forms of indigenous building as done by more primitive cultures, and usually includes the same set of climate responsive parameters and similar materials but using somewhat higher technology in the construction. It has been built to reduce the range of local climatic variations; to avoid some of the heat of the sun in hot climates, to welcome the breezes when they can provide desired cooling and to admit light in sufficient amounts for task lighting and to keep out excessive or unnecessary light. Bamboo, as an alternative building material, helps in decentralizing the construction process which has both economic and ecological advantages; to control environment conditions for human comfort.

Week 7: The Scientific Vernacular (progress)

To what degree can bamboo technology control the environmental conditions of interiors and semi-interiors compared to industrial building materials?

Introduction

From the external perspective, as objects for the eye of a distanced beholder, bamboo buildings appear first as works of art, as arrangements of volume and void and colour, as sculpture. The eye is pulled by the building’s appearance into its plan into its use; emphasizing the most important dimensions of buildings lie inside. The experience of the interior makes the provision of internal spaces to shelter people and help them order social occasions. None of these developed in extreme climates.

We humans have desire a certain minimum level of comfort inspite of the weather or location. The major elements of climatic environment which affect human comfort are air temperature, air movement and humidity through our bodily heat transfer of heat gains and heat loss and noise level. Therefore, shelter is the main instrument for fulfilling the requirements of comfort. It modifies the natural environment to approach optimum conditions of livability.

The building envelope is the physical separator between the interiors and exterior of the building. Components of the envelope are typically walls, fenestrations, roofs and floors. In this paper, a brick-concrete building is selected as a baseline with the same floor area and window ratio as the bamboo-structure building; is compared to distinguish intrinsic differences of the technical potentials of the environmental conditions of interiors and semi-interiors.

Thermal Insulation

Envelope insulation being assessed through energy use and carbon emission is identified within the boundary of the functional requirements of the building.

According to Dongwei Yu et. al., they indicate the bamboo-structured building has an embodied energy or carbon of 3003.4Mj/m² and a thermal resistance of 168.9kg CO₂/m²; in contrast to having a brick-concrete building of 3532.90Mj/m² of embodied energy used and 326.1kg CO₂/m² of thermal resistance.

The embodied energy and carbon parameters the envelope in the two types of buildings with regard to main envelope materials, bricks used in brick-concrete building have Pe.k = 2409.8 and Pc.s = 192.8 in contrast to Pe.k = 53.6 and Pc.s = 3.13 for the bamboo-structure building. Therefore, the walls of the bamboo-structure building have lower embodied energy and carbon and higher performance thermal insulation than those of the brick-concrete building. It implies that the bamboo-structure building has a promising perspective to be one of the sustainable buildings. In general, the embodied energy or carbon on a volumetric basis increases with the increasing density; while the thermal conductivity decreases with the increasing density.

Wind Pressure

Roof with walls that pass breeze but not rain is the most ideal for building by maximising natural ventilation. Both positive and negative pressures occur simultaneously when wind interacts with a building. The differences between a bamboo-structure building and a brick-concrete building are the open eaves and porous bamboo slats for walls and floor that maximize natural ventilation. The most extensive use of bamboo in construction is for the walls and partitions. They are the major elements that carry the dead load and live load of the building. An infill between framing members is required to complete the wall to protect against rain, wind, animals; and to provide in plane bracing to ensure the overall stability of the overall structure when subjected to horizontal forces.

Wind can cause an increase or decrease in pressure within the building. Internal pressure changes occur because of the porosity of the building envelope (eg, openings of doors and windows, air infiltration through walls that are not absolutely airtight).

When a building is pressurized, the internal pressure pushes up on the roof. This push from below the roof is combined with the suction above the roof, resulting in an increased wind load on the roof. The internal pressure also pushes on the side of the rear walls. This causes the roof cover damage (eg. Metal edge flashing lifted) and window damage (eg. Outer panes of windows broken) occur due to the pressure of the aerodynamic forces. The monitored wall section was subjected to air pressure differentials, outdoor-to-indoor, within ±18 Pa, which is typical for most brick-concrete buildings.

When a building is depressurized, the internal pressure pulls the roof down, reduces the amount of uplift exerted on the roof and pulls in the windward wall, which increases the wind load on external wall. Therefore, the air pressure differential outdoor-to-indoor reduces to the range in between -9 to +2Pa.

Solar Shading

Acoustic

Bamboo-structure building is also a sound barrier that drowns out noise. But, the screen must be dense and at least 3 to 8 feet wide; thus depending on the cause of the noise. According to forestry experts, bamboo has a reflection, absorption and blocking effect to sound wave. It can greatly reduce noise level by 10-15 dB. Therefore, bamboo-structure building creates a unique sound environment and soundscape. But brick-concrete building has a higher noise transmission loss of 32-36 dB. It is already known for its specified for noise barriers. According to Anderson (1984), Effects of vegetation on human response to sound, a 10 dB reduction makes a sound appear to be half as loud as our human ear does not perceive sound in a linear way. Therefore, bamboo-structure building is sufficient to reduce noise at the surroundings.

Conclusion

Modal Making Week

Inspiration from Vietnam's Bamboo Architecture

The modal below explains the understanding of the ability of the bamboo as an alternative building material.

Bamboo has offer a rapidly renewable resource. It's panelling adds beauty and flare to shelter; thus bamboo panels can be placed around posts, ceilings, walls and more.

Varied spacing and thickness of the bamboo canes creating the walls of the house, each defining a different level of fluidity from one space to the next.