Bamboo Culm Sizer

Tool Scope

Bamboo Culm Sizer is a member-level structural design tool for bamboo culms. Checks bending, shear, axial, and combined loading to ISO 22156 (2021) and IStructE Manual for the design of bamboo structures to ISO 22156:2021 (2025), and assesses durability by assigning a Use Class and evaluating proposed measures against the intended design life. Results must be reviewed by a qualified structural engineer.

Feedback & Bugs

For questions, feedback, bug reports, feature suggestions, or collaboration enquiries, please get in touch at hello@oduru.dev.

Design action effects

Bending Moment	$M$	kNm
Shear Force	$V$	kN
Compression	$P_{c}$	kN
Tension	$P_{t}$	kN

Material properties

Strength & Stiffness Data	-
Bending Strength	$f_{m, k}$	MPa
Compression Strength	$f_{c, 0, k}$	MPa
Tension Strength	$f_{t, 0, k}$	MPa
Shear Strength	$f_{v, k}$	MPa
Mean characteristic modulus	$E_{k, m e an}$	MPa

Guidance

Scheme-design material properties are being used. For detailed design, confirm project-specific material properties from graded culms, supplier data, or test results.

Reference: IStructE Manual (2025), Table 4.4.

Service conditions

Service Class	SC
Load Duration	-
Service Temperature	$T_{s}$	°C

Redundancy class

Redundancy Class

Longitudinal imperfections

Bow

b_{0}

mm/mm

Member stability parameters

Member Length	$L$	m
Effective Length Factor	$K$
Axial Eccentricity	$e$	mm

7 culms, each Ø 60 × 15.0 (mm)

Sizing parameters

Outer Diameter	$D$	mm
Wall Thickness	$t$	mm
Number of Culms	$n_{c u l m s}$

Guidance

Select design diameter and wall thickness from field measurements. If variation is 10% or less, use the average end measurements. If it exceeds 10%, use the minimum diameter along the culm and the minimum end wall thickness.

Reference: ISO 22156 (2021), Clause 6.4.1.

Max. Utilisation

76.9%

Governing:Combined Compression + Bending

Combined Compression + Bending0.769

Combined Tension + Bending0.547

Bending0.497

Compression (buckling)0.231

Shear0.138

Tension0.049

Compression (crushing)0.033

Will the bamboo contact marine or brackish water?	YesNoNot confirmed
Will the bamboo contact fresh water or aggressive in-ground conditions?	YesNoNot confirmed
Will the bamboo contact soil, be buried or remain in standing water?	YesNoNot confirmed
Will any bamboo be embedded in concrete?	YesNoNot confirmed

What Service Class applies to this member?Service Class controls mechanical properties and is separate from durability Use Class. EMC means equilibrium moisture content.
Installation moisture contentWhat is the maximum culm moisture content allowed at installation?	%
Will the bamboo be seasoned to the local equilibrium moisture content before installation?
Can the bamboo dry after accidental wetting?Confirm ventilation and a clear drying path.
For bamboo in a roof or cavity, are drainage and ventilation provided?
Negative-pressure water-ingress risk addressed?Assess if building is mechanically ventilated or air-conditioned.

Has mature bamboo been specified?	YesNoNot confirmed
Were locally appropriate harvesting practices followed and documented?	YesNoNot confirmed
What preservative treatment is specified?
Is wood-boring beetle attack a credible local risk?
Is subterranean termite attack a credible local risk?
Are subterranean termite paths disrupted and inspectable?Use an elevated plinth, visible inspection gap, barrier or equivalent strategy.

Where is the member located?
Can water collect in or enter the bamboo?Are there exposed culm ends, upward-facing openings and details that trap water?
How is the bamboo separated from concrete, masonry or the foundation?