Background
The use of bamboo in architecture has recently regained new
value because of sustainability. Bamboo, as a natural, versatile,
and renewable, is generally regarded as sustainable material.
There is potential that bamboo can be used more extensively in
all parts of a building, as architectural and structural elements.
One of the most critical issues of bamboo being used in a
building structural system is durability. Currently there is no
building standards or regulations regarding its performance and
maintenance. Bamboo is relatively vulnerable to insect and
fungus attack. More importantly, it has a tendency to crack easily
around the joint/connection parts. In most cases, bamboo may
be more suitable for temporary structure, rather than
permanent structure. In term of bamboo structural design, the
joint systems are the most significant aspects, as they have a
direct impact on building appearance and construction
techniques. In fact, the weaknesses of bamboo structure are
their joint systems and their inherent insufficient material
strength. In other words, if the joint system does not work
properly, the overall structure would have to be demolished
earlier than its expected lifespan. ‘Kashiihama House for All
Project’ is a pilot project in Kyushu University, in which a
temporary architecture is constructed for the purpose of
investigating the Mousou bamboo engineered joints and frame
truss system. To set up the project ‘Kashiihama House for All’,
the researchers faced many specific problems that were similar
to the real constructions: such as budget, construction period,
self-construction, detachable structure, laws & regulations,
limited area and transportation. The research project intended to
address these problems, especially the safety concern.
The research investigated the bamboo architectural design
and construction possibilities, by utilizing the inherent structural
property of Mousou bamboo, application of effective practical
connections, and application of frame truss system. The selected
joints came from fundamental technologies commonly used in
modern bamboo architecture. ‘Bolted Joint’ and ‘MortarInjection’
can be used along with bolted joint, to fix a bolt inside
bamboo, preventing it from crushing against perpendicular force.
The advantages from using both of these joints include
convenience, effectiveness, workability, etc. If bolted joint is
used along with mortar injection, the bamboo structure would
become permanently fixed and undetachable. In this case, the
requirement of the ‘Kashiihama House for All’ or ‘KHFA’ project
program would not be met, and transportation would become an
issue. The commonly-used post-tension construction connection,
‘Sheath Steel Tube’, would be inserted through the drilled hole
to prevent mortar concrete from solidifying the joint.
1.2 Objectives
There are four objectives of this research. 1) A bamboo
structural and joint system was investigated. 2) The overall
structural design was improved through material basic strength
experiment, joints and frame experiments. 3) Potential lightweighted
detachable building components were examined. 4) A
pilot project ‘Kashiihama House for All’ was constructed with all
the construction term issues resolved.