20-09-2012, 01:47 PM
TENSEGRITY BASED POULTRY SHED
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ABSTRACT
Tensegrity is a developing and relatively new system which creates amazing, lightweight and
adaptable structures, giving the impression of a cluster of struts floating in the air. They are a
special class of light-weight space truss structures, where the tensile elements are made of cables.
They are easy to construct and are light in weight. Another main advantage is that they can be
folded. Thus they will prove useful in coming years when structures which are space efficient
will be required.
Bamboo is a non characterized and non validated material which is readily available in
rural areas in India and has great scope as a building material.
The combination of the concept of tensegrity and bamboo as a building material has a vast
potential to result in eco-friendly, economical, structurally optimal structures which are lightweight,
earthquake resistant, transportable and storable. Thus we can have shelters or even
permanent structures made at a fraction of existing costs and still be more eco-friendly.
The objective of this project was to fabricate a “TENSEGRITY BASED POULTRY SHED”
structure using bamboo struts and jute ropes and the basics in tensegrity. Main emphasis was on
light weight quick fabrication, ease in folding and dismountability. The individual elements were
separately tested in the lab, and found suitable to resist likely loads
INTRODUCTION
DEFINITION OF TENSEGRITY AND TENSEGRITY STRUCTURES
"The word 'tensegrity' is new invention and contraction of the phrase 'tensional integrity.'
Tensegrity describes a structural-relationship principle in which structural shape is guaranteed by
the finitely closed, comprehensively continuous, tensional behaviours of the system and not by
the discontinuous and exclusively local compressional member behaviours. Tensegrity provides
to the structure ability to yield increasingly without ultimately breaking or coming asunder"
Tensegrity structures are three-dimensional space structures built of struts and cables attached to
the ends of the struts. The struts can resist the compressive force; the cables resist the tensile
forces. Most-strut-cable configuration which one might conceive is not in equilibrium, and if
actually constructed will collapse to a different shape, only strut-cable configuration in a stable
equilibrium will be called tensegrity structures.
PROPERTIES OF TENSEGRITY STRUCTURES
The tensegrity concept can be defined in terms of push and pull, where push is provided by struts
and pull is provide by cables have a win-win relationship with each other. Pull is continuous and
push is discontinuous. The two balance each other producing the integrity of tension and
compression. Tensegrity structures consists only compression struts and tension cable members.
These fundamental phenomena do not oppose, but rather complement each other. Tensegrity is
the name for a synergy between a co-existing pairs of fundamental physical laws of push and
pull, or compression and tension, or repulsion and attraction.
APPLICATIONS OF TENSEGRITY
I. The qualities of tensegrity structures which make the technology attractive for human use
are their resilience and their ability to use materials in a very economical way. These
structures very effectively capitalize on the ever increasing tensile performance modern
engineering has been able to extract from construction materials.
II. In tensegrity structures, the ethereal (yet strong) tensile members predominate, while the
more material-intensive compression members are minimized. Thus, the construction of
buildings, bridges and other structures using tensegrity principles could make them
highly resilient and very economical at the same time.
III. In a domical configuration, this technology could allow the fabrication of very large-scale
structures. When constructed over cities, these structures could serve as frameworks for
environmental control, energy transformation and food production. They could be useful
in situations where large-scale electrical or electromagnetic shielding is necessary or in
extra-terrestrial situations where micrometeorite protection is necessary. And, they could
provide for the exclusion or containment of flying animals over large areas, or contain
debris from explosions.
IV. These domes could encompass very large areas with only minimal support at their
perimeters. Suspending structures above the earth on such minimal foundations would
allow the suspended structures to escape terrestrial confines in areas where this is useful.
Examples of such areas are congested or dangerous areas, urban areas and delicate or
rugged terrains.
V. In a spherical configuration, tensegrity designs could be useful in an outer-space context
as superstructures for space stations.
VI. Their extreme resilience makes tensegrity structures able to withstand large structural
shocks like earthquakes. Thus, they could be desirable in areas where earthquakes are a
problem.
BAMBOO AS A BUILDING MATERIAL: NEED AND ADVANTAGES
There has been a furious construction activity in the developing world, especially India
and China, for the last one and a half decades. Although not directly visible, construction
industry is one of the most polluting industries in the world. Production of both concrete and
steel cause considerable deterioration of the environment.
Producing every ton of cement results in the emission of at least one ton of carbon dioxide
(CO2). Roughly 5 to 10 percent of global CO2 emissions are related to the manufacture and
transportation of cement. Similarly, production of every ton of steel is accompanied with the
release of over two tons of CO2 in the atmosphere.
The developing economies need millions of houses for their growing population, a big
part of which is homeless, the fast growth rate necessitates infrastructure development in the
form of suitable space for offices and industries. While acknowledging the need for building
more structures, it is also most important to keep the environmental issues at the forefront.
It is here that engineered bamboo can be of great value to civil engineers owing
to several noteworthy features.(Bhalla et al. ,2008)