Modern Bamboo Structures – Xiao et al.

(eds)
© 2008 Taylor & Francis Group, London, ISBN 978-0-415-47597-6

Design and construction of a two-story modern bamboo house

G. Chen
Institute of Modern Bamboo, Timber and Composite Structures (IBTCS), Hunan University,
Changsha, Hunan, China

Y. Xiao
Institute of Modern Bamboo, Timber and Composite Structures (IBTCS), Hunan University,
Changsha, Hunan, China
Department of Civil Engineering, University of Southern California, Los Angeles, CA, USA

B. Shan & L.Y. She

Institute of Modern Bamboo, Timber and Composite Structures (IBTCS), Hunan University,
Changsha, Hunan, China

ABSTRACT: The research group led by Prof. Xiao at the Hunan University and the University
of Southern California had been working on developing various new types of structure elements
using bamboo materials. One of the mile-stone projects is to design and build a modern residential
house using these new products. The demonstration house has a foot square area of about 140 m2,
and total building floor area of about 230 m2. The design attempts are to construct this modern
bamboo house essentially following the design requirements set in design codes such as the Uni-
form Building Codes for lightweight wood frame buildings in North America. This paper presents
the details of the design and some special considerations for construction.

1 INSTRUCTIONS

Lightweight wood frame structures are widely used in residential housing development in North
America. The main structural feature is to rely on uniformly spaced studs and sheets to withstand
all kinds of in-plane and out-plane forces system. The so-called “platform construction” enables
the staged construction due to the separation of walls and floors. The floor constructed in previ-
ous stage serves as a platform for the erection of the walls, upper floor structures, with minimum
requirement of heavy equipment.
The authors at the Institute of Modern Bamboo, Timber and Composite Structures (IBTCS)
of the Hunan University directed by Prof. Xiao have developed several new technologies using
bamboo in modern construction.
This paper reports the mile-stone project of building a modern bamboo residential house, which
integrates all the newly invented bamboo technologies and products.

2 DESIGN FEATURES

The bamboo building has a foot square area of approximately 140 m2, the total building floor
area is about 260 m2. The first story includes a main living room with fireplace, guest dining
area, kitchen, family dinning room, family room, guest room and two bathrooms. The floor of
the first story is elevated for 600 mm to provide natural ventilation under the floor. A two-car
garage is built on grade and attached to the main building with entrance to the family room. A
staircase connects the living room to the second story, which includes a master bedroom with

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bathroom, two family rooms with a shared bathroom, and in-house balcony overlooking the main
living room on first story. Figure 1 shows the architectural appearance of the modern bamboo
residential house.

3 DESIGN FEATURES

The modern bamboo building was designed and constructed using similar details as wood frame
structure. The height of the two stories was 2.8 ~ 3.2 m. The building adopts the platform con-
struction. The lateral load resisting system on each floor relies on the walls made of laminated
bamboo stud of about 40 mm by 84 mm in section and 10 mm thick veneer sheets. The floor
diaphragm was made of glubam beams (Xiao et al. 2007) supported on the walls and 1220 mm
by 2440 mm bamboo veneers nailed on top of the floor beams. The roof system was designed and
built by pre-assembled bamboo trusses with a spacing of 610 mm. Braces were used to provide
stability perpendicular to the truss plane.
The bamboo house was designed following the similar design procedures for wood frame build-
ings. Due to the fact that the laminated bamboo typically has higher strength and stiffness, the
house was designed with conservative assumptions.

4 MATERIAL AND STRUCTURAL ELEMENTS

The main basic material used in manufacturing the structural elements was bamboo veneers with
a dimension of 2,440 mm long, 1,220 mm thick and 28 mm thick. The veneers were further made
into various laminated structural elements using the glubam technology developed by Xiao et al.
(2007). The authors are currently conducting several tests for quantifying the structural behavior
of various laminated bamboo elements. Figure 2 shows the test setup of the bamboo roof truss.
The shear wall tests are scheduled to perform in near future.

Figure 1. Perspective drawing of modern bamboo house built by IBTCS.

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Figure 2. Laminated bamboo truss test at IBTCS.

5 CONSTRUCTION PROCESS

5.1 Foundation
A raised floor system was designed to elevate the living space off the ground, isolating it from
moisture and pests. Figure 3 shows several procedures of foundation construction. Clearance
between the bottom of the joists and the ground is 600 mm. The bamboo house site partially
occupied the existing spread concrete mat of a previous masonry building, thus concrete mat was
extended to cover the entire foot plan. Perimeter cripple walls were made by concrete filled hol-
low concrete masonry blocks on concrete strip foundation. Concrete blocks were also used to built
pedestals to provide supports of joists within the perimeter of the house. Sill plates were anchored
on top of the cripple walls and concrete block pedestals using 12 mm diameter bolts spaced less
than 800 mm and embedded 200 mm deep in the concrete infill. Asphalt sheets were used as
moisture insulation between the sill plates and the footing. The exteriors of the cripple walls were
coated with asphalt also.
The elevated space under the first story floor was ventilated by providing openings on the
cripple walls, which satisfied the typical requirements of 0.067 m2 for every 14 m2 of plan area
(1 square foot per 150 square feet).

5.2 Bamboo framing wall

The wall framing are consisted of laminated bamboo studs, top plates, bottom plates and headers.
Figure 4 illustrates the installation of stud walls. Studs in exterior walls of this two-story building
had a cross section of about 40 mm by 84 mm, roughly equal to the size of 2 × 4 lumber used
in the North American market. The stud spacing was 406 mm in exterior walls of the first floor,
whereas 610 mm in the second floor. The walls are filled with heat-insulation wools. The bottom
plates and top plates of wall framing usually act as a fire-stopping. The walls were sheathed with

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(a) Excavation foundation (b) Concrete filled masonary block footings

(c) Sill plates (d) Ventilation opening on cripple wall

Figure 3. Construction of foundation.

Figure 4. Installation of laminated bamboo walls.

bamboo veneer panels that were attached vertically to the wall frame. The panels were connected
to the wall frame studs and top and bottom plates using nails spaced 150 mm on center along the
panel edges and 300 mm along the intermediate studs. The exterior cladding included waterproof
underlayment, wire mesh and stucco mortar cladding surface. The gypsum panels were attached
to framing with screws spaced 305 mm on center along the panel edges and intermediate studs to
form the interior sheathing of walls.
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(a) First floor joists (a) Connection detail for joists

(c) First floor sheathing (d) Second floor joists and sheathing

Figure 5. Construction of floor systems.

5.3 Floor system

The floor system included glubam joists and the veneer sheathing on top of the joists. The primary
joist was 84 mm wide by 185 mm deep and the secondary joist was 56 mm wide by 185 mm deep.
The primary joists were supported on foundation blocks or walls whereas the secondary joints
were supported on the primary joists using steel angle brackets. The bamboo veneer sheathing
panels where affixed on top of the joists using nails or screws at a spacing of about 150 mm along
the panels edges and 300 mm along the intermediate joists.

5.4 Roof system

The laminated bamboo roof trusses were prefabricated at the facility in the nearby laboratory.
The prefabricated trusses were then carried on the platform on top of the ceiling of the second
story. The roof trusses were erected and installed on the load-bearing walls of the second story.
Wood blocks were used to maintain the spacing of 610 mm between the trusses. After making
sure each truss was vertical, lateral braces were set in place to keep the stability in the direction
perpendicular to the truss plane. The bamboo veneers sheets of 2,440 long by 1,220 wide (or 8 ft.
by 4 ft.) were than nailed on the slopes of the trusses, with the longer dimension perpendicular to
the truss rafters. The bamboo panel sheets were staggered to avoid continuous seams in the short
direction. Two layers of waterproof underlayment were affixed on the surface of the bamboo
veneer sheathing. Glazed clay tiles were last installed using two nails for each tile. The roof for
the garage used slightly different system. The spacing of the trusses was 1,220 mm and purlins
were used to interconnect the truss rafters and to provide the underneath supports for the roof
sheathing.
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 (a) Moving prefabricated truss to site (b) Erection of prefabricated truss

(c) Alignment of roof trusses

(d) Installation of roof sheathing

(e) Affixing waterproof underlayment (f) Installation of concrete tiles

Figure 6. Roof construction process.

6 CONCLUSION

Using the newly invented laminated bamboo structural elements, a two-story, 260 m2 floor area
modern bamboo house was designed and constructed. The project demonstrated that the modern
bamboo building can be constructed using many similar procedures and details as the wood frame
structures.

ACKNOWLEDGEMENTS

The research described in this paper was conducted at the Institute of Bamboo, Timber and
Composite Structures (IBTCS) of the Hunan University, under the support from the Program
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Figure 7. Completion of main structure of bamboo house as of December 2007.

for Changjiang Scholars and Innovative Research Team Project by the Ministry of Education of
China (Project No. IRT0619).

REFERENCES

GB50005. 2003. Code for design of timber structure. Ministry of construction of China. 2003.
Xiao, Y.; Shan, B.; Chen, G.; Zhou, Q.; and She, L.Y. 2007. Development of A New Type of Glulam—
GluBam, Proceedings of the International Conference on Modern Bamboo Structures. ICBS-2007.
Changsha. China. Oct. 28–30.

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