Bamboo in Bioconstruction

Would you like to build your own Bamboo house?

Bamboo can have different uses in construction:

– It can be used as submerged foundation reinforcement in concrete (with cement or lime) as an alternative to steel.
– The complete supporting structure can be constructed, from the columns to the beams/ribbings, including the roof battens.
– Can be combined with any type of wall and insulation: straw, straw/mud, vegetable fibres, mineral wool.
– Can be built on any load-bearing wall (brick, thermo-clay, etc.)

For the dimensioning of our Guadua structures we have a solid calculation base that can be used as a reference in Europe; Colombian Standards of Earthquake Resistant Construction in Guadua NSR-10, title G12.

At the fireproof level, we assume that bamboo is classified as a building material in the German standard DIN 4102 with class B2 (low flammability).

Static resistance

Bamboo has very high resistance values to all types of longitudinal stresses parallel to the fiber. In bending, tensile and parallel compression, their strength values or elastic limits are generally higher than those of wood normally used in construction (pine, spruce), in some cases approaching steel.

Earthquakes behaviour

The proper nature of bamboo, its cylindrical shape with fiber accumulation on the outer face, and its high degree of elasticity make it especially suitable for seismic-resistant constructions.

Historically, bamboo constructions have always had a high degree of safety in addition to this good resistance to earthquakes because, in addition to their great elasticity, the structures are particularly light and have a high capacity for absorbing energy.

General Properties of Bamboo for Construction

· Density (dry): 500-800kg/m3
· Culm height: 6-25m
· Internodal space: 250-500mm
· Diameter: 50-200mm
· Modulus of elasticity E: ~7000-17 000N/mm2
· Wall thickness: >10% of outside diameter

Structural bamboo species used worldwide

Scientific name (local)

Guadua angustifolia Kunth

Dendrocalamus strictus (Calcutta)

Bambusa Vulgaris

Phyllostachys edulis (Moso)

Dendrocalamus asper (Petung)

Bambusa blumeana (Spiny/Thorny)

Gigantochloa apus

Zones

America

Asia

Asia, America

Asia

Asia, America

Asia, Pacific Asia

Asia

Max diámeter.

120-160 mm

25-80 mm

80-150 mm

120-180 mm

80-200 mm

60-150 mm

40-100 mm

Comparison of characteristic design forces of dry bamboo* and free of visual imperfections (cracks, etc.)

10 minute load test (Kg/cm2)

*Moisture content 12% /”Mature” crops ( 3-5 years)

Flexure

Traction

Compresssion

Flexure

Traction

Compresssion

 C24 Softwood

Flexure

Traction

Compresssion

Bamboo elastic modulus with 12% and 19% moisture content

Moisture content

12%

19%

Average Elasticity Modulus (N/mm2)

10.000/17.000

8.500/15.000

Reduced modulus E0.05 (N/mm2)

7.500/13.000

6.700/8.000

Fire resistance

Bamboo is a material classified as suitable for construction according to German Standard DIN4102 with class B2 (low flammability). The high concentration of silica on the outside slows down the propagation of the flame and can thus be assimilated to wood when carrying out fire resistance calculations. The reaction to fire value is very similar to wood and is set at 0.6mm/min.

The preservation treatment by immersion in Borax salts and boric acid that our Guadua bamboo canes receive, adds an extra fire resistance, because this mixture acts as a fire retardant.

For exposed bamboo structures, a fire retardant coating material similar to those applied to wood structures will be applied to increase its resistance to combustion without the need to thicken its section.