A presentation given at the Global Bamboo and Rattan Congress (BARC 2018), 25-27 June 2018.

2. Contents

3. Introduction
There are three producing areas of bamboo in the world

4. Distribution map of bamboo in China
Moso bamboo

5. Application of raw bamboo in engineering
Bamboo house Bamboo bridge
Bamboo Landscape architecture Bamboo scaffolding

6. Defects of raw bamboo
decay and insect attackIrregular hollow shape
Joints are very complicated and difficult to fabricate
wire Metal connector bolt nylon or plastic

7. Engineered bamboo
Glubam
LBLBP
PSB
Bamboo plywood
Laminated bamboo lumber
(LBL)
Glubam
Parallel strand bamboo

8. Mechanical behavior of LBL
Specimens in tension Specimens in compression
• No standards about engineered bamboo are available
• LBL was tested according to ASTM D143-14

9. Failure modes
Cracking in glue-lines Folding Cracking in layersBrittle fracture
Specimens in tension: Brittle fracture
Specimens in compression: Cracking in glue-lines, Folding, Cracking in layers

10. Main test results
in tension
in compression
in tension in compression
strain
stress

11. Comparison between test and theoretical results
elastic limit
peak failure
 
 
2 3
0 1 2 3
0
=
c ec
c ec u
u u uc cf
E
k
  
           
     
 

    
    
fc uc
fc uc
k
 
 



The theoretical model suggested was found to be in
good agreement with the experimental data.
theoretical model
Origin point

12. Wood I joist
rooffloor
Brittle fractureTapered groove and web

13. OSB webbed bamboo i shaped beam
gluing nailing
planing
curing
Technical requirements
1.Web nailed and bonded to flanges
2.Nail spacing: 150mm
3.Consumption of adhesive：250g/m2
4.Curing time: 14 days
④
① ②
③

14. 1.Four point bending test
2.Loading speed: 2mm/min
Test setup
stiffeners at supports stiffeners at concentrated load

15. Details of composite joists without opening
specimen b×t/mm H/mm l1/mm shear span ratio λ stiffener
24I1 59.5×35 240 336 1.4 -
24I2 59.5×35 240 384 1.6 -
24I3 59.5×35 240 432 1.8 -
24I4 59.5×35 240 480 2.0 -
24I5 59.5×35 240 600 2.5 -
24I6 59.5×35 240 720 3.0 -
24I7 59.5×35 240 336 1.4 yes
24I8 59.5×35 240 384 1.6 yes
24I9 59.5×35 240 432 1.8 yes
24I10 59.5×35 240 480 2.0 yes
24I11 59.5×35 240 600 2.5 yes
24I12 59.5×35 240 720 3.0 yes

16. Failure mode
Delamination of OSB
twist
web shear failure
Cracks in glue-line
Specimen after testing

17. Test results
specimen Pcr Pu Pn Du Pn/Pu
24I1 15.83 25.83 25.64 8.10 99.3%
24I2 13.27 23.21 21.82 8.76 94.0%
24I3 12.36 22.40 18.82 9.36 84.0%
24I4 11.25 21.26 17.00 10.19 80.0%
24I5 9.87 17.87 14.68 10.47 82.1%
24I6 7.86 13.88 10.41 11.25 75.0%
24I7 13.77 26.72 26.43 8.28 98.9%
24I8 12.68 25.68 23.75 9.30 92.5%
24I9 11.18 23.18 21.22 9.52 91.5%
24I10 11.68 22.67 19.17 10.47 84.6%
24I11 10.19 20.21 14.73 11.43 72.9%
24I12 8.06 16.06 13.11 12.39 81.6%
Pcr: cracking load；Pn : load at serviceability limit states; Pu : load at ultimate limit states；Du :
mid-span displacement

18. 4 OSB webbed bamboo i shaped beams with
web opening
pipesventilation system
Wood joists with web opening

19. methods
Control specimen
clear distance between holeshole shape hole size

20. detail of specimens with web opening
specimen H(mm) hole shape d/h l1(mm) l(mm)
24I1 240 - 0 - -
24CI1 240 circle 25% 500 -
24CI2 240 circle 50% 500 -
24CI3 240 circle 75% 500 -
24CI4 240 circle 100% 500 -
24SI1 240 square 25% 500 -
24SI2 240 square 50% 500 -
24SI3 240 square 75% 500 -
24SI4 240 square 100% 500 -
24SI5 240 square 50% 330 170
24SI6 240 square 50% 287.5 255
24SI7 240 square 50% 245 340
24SI8 240 square 50% 202.5 425
24SI9 240 square 50% 160 510
30SI2 300 square 50% 500 -
H: height of composite beams；d : hole size; l 1 : distance between hole and support ；l : clear
distance between holes

21. d/h≤25%
d/h=75%
d/h=50%
d/h=100%
tension
compression
Failure modes (circle hole)
For specimens(d/h≤25%):
Delamination of osb in flanges
For specimens(d/h≥50%):
Web shear failure

22. Failure modes (square hole)
d/h=25% d/h=50%
d/h=75% d/h=100%
400-600

23. • The results showed that holes in the web have considerable effect on the strength reductions of specimens.
• For small holes (d/hw≤25%), the effect of the hole could be ignored.
• The cracking for the holes started at an angle about 400-600
Displacement
Load
hole size

24. hole shape
• It is conservative that the carrying capacity of beams with a square web hole can be
treated the same as a circular hole that inscribes the square hole.
240mm depth beams
Load
Load
circle hole
square hole square hole
circle hole
300mm depth beams

25. 1d 1.5d
2d 2.5d
2.5dd d
influence of distance between holes

26. influence of distance between holes
• For circular and square web holes, the critical clear distance between holes with
negligible stress interaction appears to be 2 times and 2.5 times the hole diameter
respectively.
≥2D
≥2.5D
D
D
Load
circle hole
square hole
clear distance between holes
square hole
circle hole