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Determining material suitability for Low-Rise housing in the philippines: Physical and mechanical properties of the bamboo species Bambusa blumeana

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  • Base Bahay Foundation Inc.

Abstract and Figures

The use of cellulosic materials in the construction of low-rise housing in tropical climates has great potential. Bambusa blumeana (B. blumeana, J.A. and J.H. Schultes), the most abundantly available bamboo species in the Philippines, is a promising alternative material for the construction of cost-efficient buildings. However, to comply with municipal rules and regulations for construction, a comprehensive understanding of the organic raw material is needed to permit its application as a load-bearing structural member. In this study, the physical and mechanical properties of B. blumeana bamboo from a typical growth region of the Philippines were tested according to ISO 22157-1 (2004) and ISO 22157-2 (2004). The characteristic strength values of B. blumeana were as follows: compressive and tensile strengths parallel to the grain of 20 and 95 MPa, respectively; shear strength of 5 MPa, bending strength of 34.6 MPa, and the mean and fifth percentile modulus of elasticity of 13100 and 8600 MPa, respectively. Based on these results, a recommendation for permissible stresses for structural design was made in line with ISO 22156 (2004).
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Determining Material Suitability for Low-Rise Housing in
the Philippines: Physical and Mechanical Properties of
the Bamboo Species Bambusa blumeana
Corinna Salzer,a,* Holger Wallbaum,a Marina Alipon,b and Luis Felipe Lopez c
The use of cellulosic materials in the construction of low-rise housing in
tropical climates has great potential. Bambusa blumeana (B. blumeana,
J.A. and J.H. Schultes), the most abundantly available bamboo species in
the Philippines, is a promising alternative material for the construction of
cost-efficient buildings. However, to comply with municipal rules and
regulations for construction, a comprehensive understanding of the
organic raw material is needed to permit its application as a load-bearing
structural member. In this study, the physical and mechanical properties
of B. blumeana bamboo from a typical growth region of the Philippines
were tested according to ISO 22157-1 (2004) and ISO 22157-2 (2004).
The characteristic strength values of B. blumeana were as follows:
compressive and tensile strengths parallel to the grain of 20 and 95 MPa,
respectively; shear strength of 5 MPa, bending strength of 34.6 MPa, and
the mean and fifth percentile modulus of elasticity of 13100 and 8600 MPa,
respectively. Based on these results, a recommendation for permissible
stresses for structural design was made in line with ISO 22156 (2004).
Keywords: Bambusa blumeana; Bamboo; Philippines; Physical and mechanical properties; Alternative
construction materials; Housing
Contact information: a: Chair of Sustainable Building, Department of Civil and Environmental
Engineering, Chalmers University of Technology, SE-41296 Gothenburg, Sweden; b: Department of
Science and Technology (DOST), Material Science Division, Forest Products Research and Development
Institute, Narra Street, Los Banos, Laguna, Philippines; c: Base Bahay, Chino Roces Avenue, 1200 Makati
City, Metro Manila, Philippines;
* Corresponding author: salzer@chalmers.se
INTRODUCTION
Two-thirds of the new floor plan area that will be built by 2050 is predicted to be
in Asia-Pacific, Africa, and Latin America and the Caribbean (IEA 2016). Affordable,
sustainable, climate-adjusted and disaster-resistant housing is an urgent requirement in
economies that experience tremendous urban growth, disparity, and extreme weather
impacts (UN General Assembly 2015). The New Urban Agenda of the United Nations
Human Settlements Program, UN Habitat, identifies the use of local raw materials as one
key area for action to address the housing need (UN-Habitat 2015). The tremendous
resource hunger and unsustainable consumption patterns for construction and other
purposes have caused overexploitation of resources in the past, resulting for example in net
forest loss at the scale of 7 million hectares annually in the tropics (FAO 2016). For the
Philippines, this magnitude is exemplified at the country level. In 1900, the total land area
of the country was 70% covered with forest, with this value declining to 21.8% by 2002
(ESSC 2002). Policy makers in the Philippines have started to react since 2000.
Through a series of policies, the extraction of timber from the natural forests was
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Salzer et al. (2018). “Bamboo housing properties,” BioResources 13(1), 346-369. 347
restricted with only a few exceptions for plantation timber. Since 2011, a national log ban
on natural and residual forest has been active (EO23 2011). Global pathways to lessen the
resource pressure and contribute to sustainable supply chains must be developed. A large
potential lies in the utilization of alternative, renewable raw materials such as bamboo
together with sustainable production and consumption patterns for its use. The fast growth
and regeneration cycles of bamboo as well as its broad availability in the tropics make it
an ecological alternative to conventional construction materials used for low-rise housing
such as timber, concrete, and steel (Villegas et al. 2003; van der Lugt et al. 2006; Liese
and Koehl 2015). In the Philippines, the utilization of bamboo for construction has a long
tradition in rural areas (Barile et al. 2007). However, these rural structures are often
considered temporary and not disaster-resistant, as manifested in the vulnerability curves
of (Monteverde et al. 2014), which relate the intensity of typhoon damage events to the
mean damage ratio of bamboo-based houses. The historical mapping of tropical typhoons
between 1845 and 2006 indicates that annually approximately 20 typhoons pass the
Philippine Area of Responsibility (PAR), which puts it in the category of countries with
highest exposure to severe wind impacts (NASA Earth Observatory 2006). Besides
typhoons, structures in the Philippines are exposed to earthquakes, as the country is located
on the ring of fire (USGS 2017). Both typhoons and earthquakes must be considered as
design loads in structural design to provide a sufficient level of safety for their occupants
(ASEP 2016). The behavior of alternative structural building materials must be reliable and
predictable to formally approve their application for use in construction. Because the latter
constraint is not in place for bamboo in the Philippines, it was rarely applied for house
construction in the urban centers of the country until recently (Base Builds 2015). The
motivation of this paper is thus to contribute to the use of bamboo for cost-efficient and
disaster-resistant low-rise housing in the Philippines in compliance with local building
regulations.
Globally, more than 1,200 bamboo species have been recorded, and the Philippines
Forestry Sector has identified approximately 62 different species (PCARRD 1991). Each
bamboo species has characteristic anatomical, chemical, physical, and mechanical
properties, which make it more suitable for certain applications than others and often
explain its empirical utilization (Liese and Koehl 2015). A shortlist of nine economically
relevant species was identified for the Philippines according to the criteria distribution and
current utilization (Table 1) (Rojo et al. 2000). In addition, Virtucio and Roxas (2003)
mentioned the criteria of affordability in comparison to conventional building materials but
without further detail on individual species because no standard pricing for bamboo exists
in the Philippines. The most common applications considered in the assessment were
construction, furniture, handicrafts, edible shoots, and pulp. The potential use of these
species for structures such as bridges, scaffoldings, and additional structures was excluded
because they are less common locally (Rojo et al. 2000; FPRDI 2002).
Among the nine economically relevant species, five have been documented for
empirical use in construction (Rojo et al. 2000). Similar to application in timber
engineering, a careful selection of the species is important for the specific purpose of full-
culm load-bearing frame construction. A highly promising species is Bambusa blumena
(B. blumeana), locally called Kauayan-tinik, which is explained in the following according
to the criteria of distribution, empiric utilization, affordability, and previous test reports.
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Table 1. Economically Relevant Bamboo Species in the Philippines (Rojo et al.
2000)
Latin Name
Sub-Species
Name
Local Name
Distribution and Utilization
Bambusa blumeana
(B. blumeana)
J.A. and J.H.
Schultes
Kauayan-tinik
Commonly planted across the country in
various soils at low and medium altitudes.
Frequently used for construction, furniture, farm
equipment, kitchen utensils, pulp, and shoot
production.
Bambusa vulgaris
Schrader ex.
Wendland
Kauayan-kiling
Found across the country but only grows on
well-drained sandy loam and clay at low
altitudes. Used for light construction, pulp,
ornamental purposes, and handicrafts.
Dendrocalamus asper (D.
asper)
(Schultes f.)
Backer ex. Heyne
Giant bamboo
Found in some provinces of the country. Used
for construction, laminated bamboo, pulp, and
shoot production.
Bambusa merrilliana or
Dendrocalamus
merillamus
(Elmer) Rojo and
Roxa or
(Elmer) Elmer
Bayog
Endemic species found in areas with deep
fertile soil. Its tough and thick walls are
preferred for furniture, farming equipment, and
construction.
Gigantochloa atter
(Hassk.) Kurz
Kayali
Found mainly in Mindanao and some locations
further north. Used for household utensils,
handicrafts, banana props, eating, and
construction.
Gigantochloa levis
(Blanco) Merr.
Bolo
Endemic species found in selected areas of the
country. Used for edible shoots, construction,
basketry, and furniture.
Schizostachyum lima
(Blanco) Merr.
Anos
Found across the country. Ideal for woven
bamboo mats, edible shoots, and brass metal
polishing.
Schizostachyum
lumampao
(Blanco) Merr.
Buho
Endemic species found across the country.
Ideal for woven bamboo mats, baskets, fences,
spears, and flutes.
Bambusa philippinensis or
Sphaerobambos
philippinensis
(Gamble)
McClure
(Gamble)
Dransfield
Laak
Found abundantly in Mindanao near the Davao
area. Widely used as banana props.
B. blumeana is the most common raw material used by the rural population to build
traditional, vernacular buildings, which indicates its suitability for construction and its
affordability for the population, despite its thorny branches which increases the complexity
of its harvest. This species is the most widely grown throughout all the regions of the
Philippine archipelago, as shown in Fig. 1, from Northern Luzon over Visayas to Southern
Mindanao. It is native to Java, Indonesia, and Eastern Malaysia, and beyond the
Philippines, and it is cultivated in Southern China, Peninsular Malaysia, the Moluccas,
Sumatra, Borneo, India, and Indochina (Rojo et al. 2000). This type of bamboo is
commonly planted in settled areas at low and medium altitudes; it grows along riverbanks,
hill slopes, and freshwater creeks; and tolerates flooding and eroded soils (Espiloy 1986).
Researchers from outside of the Philippines have referred to it as priority species but
without a description of its frequent empirical use in traditional house construction in the
Philippines (Liese and Koehl 2015).
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Fig. 1. Map of the Philippines with its main island groups Luzon, Visayas, and Mindanao; author
processed based on NAMRIA (2017)
Endeavors have been made to map the geographical distribution and quantify the
availability of B. blumeana and other economically relevant species by the national and
regional offices of the Department of Natural Resources in the Philippines (ERDB 2012).
However, it was not possible to develop an updated, consistent, country-wide map of
bamboo availabilities. One of the reasons for the knowledge gap in distribution and
quantification might be that the bamboo market is highly fluctuating, with uncertain price
points and clear cutting of existing stands in favor of one-time income opportunities for
temporary utilization (Base Builds 2015). The training and implementation of sustainable
harvesting practices is therefore also crucial for bamboo (Virtucio and Roxas 2003). In the
Philippines, agriculturally managed clumps yield approximately 800 to 1200 culms per
hectare per year, while the unmanaged natural clumps produce approximately 500 to 700
culms per hectare per year (FPRDI 2002). According to local forestry experts, a plantation
in a degraded open land plot of 7 m × 7 m has an unfertilized clump yield of 11.6 tons dry
weight per hectare per year. The fertilized clumps yield approximately 19.4 tons dry weight
per hectare per year (Virtucio and Roxas 2003). Most commonly, the species is available
in unmanaged patches, which are not usable for agricultural cash crops. Therefore, its yield
has potential to provide a side income for farmers, even though it is not maximized
compared with plantation growth (BSI 2015).
In the past and through recent research, major advancements have been achieved in
the anatomical, morphological, and chemical characterization of bamboo culms (Liese
1974; Londono 2006; Sharma et al. 2011; Liu et al. 2014; Sanchez-Echeverri et al. 2014).
In addition, the mechanical performance of culms from various species around the globe
has been subject to scientific research both in the past, such as by Janssen (1980), and in
recent years, such as by Luna et al. (2012). Because of its relevance and distribution, B.
blumeana has been studied in the past in Malaysia and the Philippines (Espiloy 1986;
Espiloy 1992; Latif et al. 1992; Latif and Tamizi 1992). Because of the absence of both
national and global bamboo standards at the time of the studies, the Indian Standard IS
6874 (1973), today updated to IS 6874 (2008), and a merger of the Indian Standard IS 6874
(1973) with a modification of the ASTM D143-94 standard (1994), today updated to
ASTM D143-14 (2014), have been applied in Malaysia and the Philippines, respectively.
The studies support the potential suitability of the species for construction and indicate that
three- to four-year-old B. blumeana has a high relative density, compressive strength, and
modulus of elasticity (MOE) during static bending. The latter are discussed in the
Discussion section in comparison with results of the current paper. In summary, the wide
distribution, empirical utilization, and promising past scientific findings of B. blumeana
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Salzer et al. (2018). “Bamboo housing properties,” BioResources 13(1), 346-369. 350
are considered a good indicator for its economic and technical potential. However, only
design values obtained through a standardized, comparable norm will enable its formal
approval for the construction of buildings and facilitate its greater acceptance and
comparability as a building material (Harries et al. 2012).
In 2004, the International Standards ISO 22157-1 (2004) and ISO 22157-2 (2004)
were released, which enabled a uniform and transparent strength grading and comparison
of bamboo species around the world. This standard has guided subsequent studies for Latin
American Guadua species (Correal and Arbeláez 2010; Ordonez-C. and Barcenas-P. 2014;
Zaragoza-Hernandez et al. 2015). In Asia-Pacific, the standard was applied for testing
bamboo species from China, Indonesia, and Thailand (Deng et al. 2016, Made Oka et al.
2014, Nugroho et al. 2013, Sompoh et al. 2013, and Suhelmidawati et al. 2012). However,
no Philippine bamboo species has been examined yet according to this standard. Therefore,
the scope of this research was to identify the physical and mechanical properties of the
economically and technically relevant Philippine bamboo species B. blumeana according
to ISO 22157-1 (2004). The documented results include the physical properties of relative
density, moisture content (MC), and shrinkage characteristics as well as the mechanical
properties of bending strength, shear strength, and compressive and tensile strengths
parallel to the grain. The results are set in comparison with results for further bamboo
species tested according to the same standard around the globe. The paper concludes by
providing a recommendation for permissible stresses of the selected bamboo species for
low-rise housing according to ISO 22156 (2004). The research on testing B. blumeana
strength according to ISO 22157-1 (2004) is expected to incentivize designers, authorities,
and people in need of housing to consider round bamboo as a valid alternative to the
available but costlier conventional building materials or scarce timber in the country.
EXPERIMENTAL
Materials and Methods
ISO 22157-1 (2004) and ISO 22157-2 (2004) were used to determine the physical
and mechanical properties of B. blumeana. In the following, the tall grasses with woody
jointed stems are referred to as culms (Liese and Koehl 2015). A culm is a single shoot of
bamboo that is usually hollow, except at nodes which are often swollen (ISO 22157-1
2004). Culms are further characterized by internode distances, the culm diameter and culm
wall thickness, as well as the length along the axis (Lui et al. 2016). Twenty-five culms of
three- to four-year-old bamboo were collected from the sourcing location at Pagsanjan,
Laguna, Region IV in Luzon. Each property was tested in 10 specimens at the Physics and
Mechanics Laboratory, Forest Products Research and Development Institute (FPRDI
2015). Each culm was cut into 4-m-long pieces starting from the butt, with a height of
approximately 1 m from the ground serving as a reference. Several studies have reported
the change of physical and mechanical properties along the culm axis (Kamruzzaman et al.
2008; Correal and Arbeláez 2010; Anokye et al. 2014; Made Oka et al. 2014). Researchers
have explained the latter with changes in the anatomical, morphological, and chemical
composition in vertical direction. To properly reflect the variation within a culm, testing of
the butt, middle, and top portions is a requirement according to ISO 22157-1 (2004). The
culms were labeled with a culm number and their height before they were cut. While still
in green condition, the culm weight, wall thickness, number of nodes and internodes,
diameter, and length were measured before the tests. Testing in dry condition is
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recommended for commercial purposes, whereas for scientific research, testing may be
performed in green condition ISO 22157-1 (2004). For this study, culms were tested
consistently in green condition. MC adjustment of results is standardized in timber
engineering, as in (EN384 2010). However, similar to timber engineering, values in green
condition are considered conservative because the strength properties increase with
decreasing MC, particularly below the FSP. Researchers described this behavior and
started to set the FSP and evaluate the effect of MC adjustment for selected bamboo species
(Jiang et al. 2012; Wang et al. 2013; Xu et al. 2014; Gutierrez et al. 2015). Regarding G.
angustifolia Kunth, Gutierrez et al. (2015) observed that the geometric and mechanical
properties are not expected to vary considerable with a MC over the fiber saturation point
(FSP) of 32% +/3%. Xu et al. (2014) confirmed that no further degradation of mechanical
properties was observed above a MC of 30% for Phyllostachys pubescens (P. pubescens).
Wang et al. (2013) and Jiang et al. (2012) set the FSP for P. pubescens lower at
approximately 23% MC. Jiang et al. (2012) attested that the MC variation influences
mechanical properties differently. While below the FSP, compression parallel to the grain
and shear strength for P. pubescens had a change rate of 3.8% and 3.1% with each 1% of
MC increase respectively, tension parallel to the grain and bending strength varied 1.6%
and 1.5% respectively. Testing in green condition is considered conservative for this study.
Therefore, the MC of B. blumeana specimen was consistently clearly above any of the
mentioned bamboo FSP during testing.
The tests were conducted at 27 °C ± 2 °C and 70% ± 5% relative humidity (RH).
The universal testing machine (UTM) that was used for measuring the bending, shear, and
tensile strengths had a loading range of 2 to 10 tons. The UTM for the compressive strength
had a maximum load of 90 tons. The MC values after each test were measured for each
specimen to appropriately interpret the results. In timber engineering, preservative
treatment affects the strength and stiffness properties of timber (Eurocode 5 EN 1995-1-1
2004). The treatment effect was excluded from this study, as untreated bamboo culms were
used. Future work is needed to evaluate whether these or other factors are valid for bamboo.
Data Evaluation
The data were processed according to ISO 22157-1 (2004), analysis of variance
(ANOVA), and ISO 22156 (2004). The formulas provided in ISO 22157-1 (2004) were
used to calculate the physical and mechanical properties from the test readings. ANOVA
tests for the statistical relevance were performed. To derive the characteristic strength
values, the raw data were transformed into characteristic values according to ISO 22156
(2004) using the following equation,

(1)
where Rk is the characteristic value (N/mm2), R0.05 is the 5th percentile value of the sample
(N/mm2), s is the standard deviation of the sample, m is the mean value of the sample, and
n is the size of the sample.
Physical Properties
Moisture content
Samples with dimensions of 25 mm in width and height and their natural wall
thickness were taken from the bending samples near the location of failure. The samples
were weighed to an accuracy of 0.01 g and oven-dried at 103 ± 2 °C. The MC of each
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Salzer et al. (2018). “Bamboo housing properties,” BioResources 13(1), 346-369. 352
sample was calculated using Eq. 2,

 (2)
where m and mo are the mass (g) of the test piece before and after drying, respectively.
Relative density
Samples of similar size to those for the MC determination were obtained, and their
maximum volume was measured using water immersion or displacement methods. The
samples were exposed to room temperature and subsequently placed in a drying oven at
103 °C ± 2 °C until a constant weight was attained. The relative density of each sample
was computed using Eq. 3:

 (3)
where ρ is the mass volume 
, m is the mass (g) of the test piece in the oven-dry
condition, and V is the green volume of the test piece during the test (mm3).
Shrinkage
To determine the amount of shrinkage, the samples were soaked in water to obtain
the initial weight and volume in green condition. Round culms at internode sections with
heights of 100 mm were taken from each bending test sample. For each sample, four
diameters, four wall thicknesses, and two lengths were measured. These samples were
dried in ambient conditions and subsequently oven-dried at 103 °C ± 2 °C until the weight
became constant. The shrinkage from the initial condition to the oven dry condition was
calculated using Eq. 4,

 (4)
where I is the initial reading and F is the final reading.
Mechanical Properties
Compressive strength
Specimens without a node were taken from the bending samples with a specimen
height equal to the outer diameter. Special attention was made to ensure a precise cut at the
end planes that was perpendicular to the grain and a vertically centered placement of the
specimen. Melted sulfur was then coated on the ends of the samples to ensure a uniform
distribution of the load weight and to reduce the friction between the bamboo and the steel
plates. The load was applied continuously during the test at a constant rate of 0.01 mm/s.
The compressive strength was determined using Eq. 5,
 
, (5)
where  is the ultimate compressive stress (N/mm2), Fult is the maximum load at
specimen failure (N), and A is the cross-sectional area calculated as,
 (mm2) (6)
where D is the outer diameter (mm) and t is the wall thickness (mm).
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Tensile strength
The specimens were wedge-shaped and the cross-sectional dimensions of the gauge
portion of the sample were measured to an accuracy of 0.1 mm. The load was applied at a
constant rate of 0.6 mm/min until the maximum load was attained. The strain gauges or
deflection were read every 0.050 tons. The ultimate tensile strength () in N/mm2 was
determined using Eq. 7,
 
, (7)
where Fult is the maximum load at specimen failure (N) and A is the cross-sectional area of
the gauge portion (mm2).
Shear strength
The shear strength along the fibers was tested with specimens of length equal to
their diameter. An equal number of specimens with and without nodes were tested. Special
attention was made to ensure a precise cut at the end planes perpendicular to the grain and
a vertically centered placement of the specimen. The wall thickness and height of the
samples were measured taken at four shear planes. The load was applied continuously
during the test at a constant rate of 0.01 mm/s with a 1-kN stabilizing load. The ultimate
shear strength (τult) in N/mm2 was calculated using Eq. 8,
 
, (8)
where Fult is the maximum load at specimen failure (N) and (t × L) is the area of four
shear planes as the product of the thickness and specimen height.
Bending strength
The bending strength was determined through four-point bending tests. The outer
diameter of the culms multiplied by 30 resulted in the free span of the specimen. On each
side of the culm, two wood saddle supports were placed 23-cm apart and mounted onto
two steel supports on a wooden beam. Similarly, the load application on top of the culm
was arranged. The ultimate strength σ in bending in MPa was computed using Eqs. 9
and 10,
 
 (9)
 (10)
where F is the maximum load (N), L is the free span (mm), D is the outer diameter (mm),
and IB is the second moment of area (mm4).
The MOE was given by the slope of the linear part of the loaddeformation
diagram. The MOE was calculated using Eq. 11 for the four-point bending test in ISO
22157-1 (2004):

, (11)
where F is the maximum load (N), L is the free span (mm), IB is the second moment of
area (mm4), and
is the deflection at mid-span (mm).
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RESULTS AND DISCUSSION
The culm diameter of the specimens ranged from 70.6 to 109.2 mm; the maximum
diameter of the middle portion was slightly higher than that at the bottom portion. The
mean diameter declined from the bottom to the top of the culm by 14%. Because of the
conic characteristic of the culms, the wall thickness was highest at the butt, with a
significant mean decrease of approximately 70% toward the top, with 24 to 7 mm
respectively. The typical length of the B. blumeana culms was 16.9 m. The minimum,
maximum, and mean geometry of the test specimens are documented in Table 2. In a
previous study in the Philippines, the geometric properties of B. blumeana culms were
comparable in terms of wall thickness, but a 41% decrease in diameter toward the top was
documented (Espiloy 1992). This may be explained by the length of the culms considered
in the previous study. In Malaysia, Latif et al. (1992) found a comparable diameter of 81
mm at the top portion, but a 10% smaller diameter and 40% thinner wall thickness of the
butt samples. The latter may again be attributed to the specimen selection process, but also
due to the different sourcing location. Overall, diameters and wall thicknesses documented
in (Espiloy 1992; Latif et al. 1992) can be described as of comparable range to this study
and are stated in Table 2.
Table 2. Geometric Characteristics of B. blumeana Test Specimens of This and
Previous Studies
Species, Country, Source
Diameter (mm)
B
M
T
B
M
T
B. blumeana Philippines
(authors), m
94.0
91.2
80.9
24.0
10.0
7.0
B. blumeana Philippines
(authors), range
78.2
to
104.3
81.3
to
109.2
70.6
to
96.5
19.2
to
27.4
7.6
to
14.0
6.2
to
7.6
B. blumeana Philippines
(Espiloy 1992), m
90.0
84.0
53.1
24.0
11.0
6.0
B. blumeana Malaysia
(Latif et al. 1992), m
85.0
87.0
81.0
14.6
10.3
8.2
B, butt of culm; M, middle of culm; T, top of culm; m = mean of sample
Physical Properties
The MC confirmed that all the bamboo specimens were tested in green condition.
It was clearly above any FSP set by researchers for other bamboo species. The MC
decreased characteristically from the butt to the top, as attested by earlier studies on
bamboo, such as Anokye et al. (2014) and Wakchaure and Kute (2012). The reduction of
MC toward the top can be attributed to the declining share of lignin matrix from the butt to
the top (Liese 1974).
The shrinkage of the culm wall thickness from the green condition to oven-dry
condition was 6.16%, 8.81%, and 4.01% at the butt, middle, and top, respectively. The
decline of the shrinkage from the butt to top of the culms is equally connected to a lower
proportion of parenchyma cells at the top of the bamboo culm, as shrinkage is mainly
caused by the behavior of the matrix (Liese 1974; Kamruzzaman et al. 2008; Huang et al.
2014). The mean radial shrinkage of the wall thickness was the largest (6.33%), followed
by the tangential shrinkage of the circumference (5.13%), with a ratio of 1.23:1.0. This
ratio fell between what Espiloy (1992) reported for B. blumeana and Anokye et al. (2014)
for Gigantochloa scortechinii (G. scortechinii) and Bambusa vulgaris (B. vulgaris), where
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a mean ratio of 1.41:1.0 and 1.15:1.0 was observed, respectively. Longitudinal shrinkage
was minimal with 0.5% at the butt and middle and 0.2% at the top of the test culm. The
mean result of 0.4% fell between the results of Anokye et al. (2014) on G. scortechinii and
B. vulgaris, Correal and Arbelaez (2010) on Guadua angustifolia Kunth (G. angustifolia
Kunth) and Zaragoza-Hernandez et al. (2015) on Guadua aculeata (G. aculeata), where
mean shrinkage values along the longitudinal axis of 0.3%, 0.6%, 0.5%, and 0.1%,
respectively, were observed.
The relative density was 517 kg/m3, 559 kg/m3, and 634 kg/m3 at the butt, middle,
and top, respectively. It significantly increased from the butt to the top of the culm with a
p-value of 0.05. This increase is attributed to the change in percentage of vascular bundles
to parenchyma. Liese (1974) specified that the total number of vascular bundles decreases
steadily with the height of the culm, whereas at the same time their closeness increases,
and the parenchyma content decreases. An increase in fiber to parenchyma ratio explains
the increase in density toward the top. With the relative density being an important
indicator property for mechanical properties (Janssen 1980; Espiloy 1992; Trujillo 2017),
the increase positively affects the mechanical properties toward the top, as will be observed
in the results presented below. The average density was observed to be 570 kg/m3. In
previous studies of B. blumeana, relative densities of 578 kg/m3 (Latif et al. 1992) and 644
kg/m3 (Espiloy 1992) were reported. Compared with other tested species reported by Latif
et al. (1992) and Espiloy (1992), these values were considered high. A density of 852
kg/m3, which is 49% higher, was reported for B. blumeana from Thailand tested in dry
condition. In comparison with other bamboo species tested in green condition according to
ISO 22157, the relative density of B. blumeana is in the medium range. Guadua velutina
(G. velutina) and Guadua amplexifolia (G. amplexifolia) have 25% and 15% lower relative
densities, respectively (Ordonez-Candelaria. and Barcenas-Pazos 2014), whereas that of
G. aculeata is comparable to that of B. blumeana (Zaragoza-Hernandez et al. 2015). For
G. angustifolia Kunth and P. pubescens, 30% and 26% higher relative densities were
reported by Correal and Arbelaez (2010) and Deng et al. (2016), respectively. Sompoh et
al. (2013) compared the relative density of B. blumeana with other species tested in dry
condition and reported 7% to 10% lower results for Bambusa bambos (B. bambos),
Dendrocalamus asper (D. asper), and Dendrocalamus hamiltonii (D. hamiltonii).
Compared to the results for B. blumeana of this study tested in green condition, the relative
densities for B. bambos, D. asper, and D. hamiltonii were 34% to 44% higher, which
highlights the change of properties below the FSP of bamboo species.
Examination of the radial distribution of the density has revealed that the weaker
interior regions of the bamboo cross section can be attributed to lower fiber density, as
identified through nano- and microscale studies such as (Tan et al. 2011; Dixon and Gibson
2014; Liese and Koehl 2016). This aspect was not further evaluated in this study, as the
construction system uses the full culm.
The raw data of the physical properties of three- to four-year-old B. blumeana of
this study are presented in Table 3, in comparison with previous test results on the same
bamboo species from other sourcing locations and test standards or test conditions. The
raw data of the physical properties of other bamboo species tested according to ISO 22157
is compared to the results of this study in Table 4.
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Table 3. Physical Properties of B. blumeana According to ISO 22157 and Different Test Standards and Sourcing Locations
Species,
Country, Source
Moisture Content
(%)
Relative Density
(kg/m3)
Shrinkage Wall
Thickness (%)
Shrinkage Outside
Diameter (mm)
Shrinkage Length
(mm)
B
M
T
All
B
M
T
All
B
M
T
All
B
M
T
All
B
M
T
All
B. blumeana
Philippines
ISO22157
(2004)
(authors), m
97.6
75.4
62.1
78.4
517
559
634
570
6.2
8.8
4.0
6.3
3.6
6.6
5.2
5.1
0.55
0.52
0.19
0.42
B. blumeana
Philippines
ISO22157
(2004)
(authors), range
74.2
to
121.5
60.8
to
92.2
36.9
to
84.2
423
to
607
440
to
639
500
to
766
2.5
to
10.3
3.3
to
19.8
0.9
to
9.0
2.4
to
5.0
3.8
to
19.8
4.3
to
6.3
0.14
to
1.74
0.08
to
0.95
0.04
to
0.06
B. blumeana
Philippines
IS6874 (1973)
(Espiloy 1992),
m
107.2
90.7
80.4
92.8
587
650
694
644
11.3
13.7
11.0
12.0
8.9
9.9
6.8
8.5
B. blumeana
Malaysia IS6874
(1973)
(Latif et al.
1992), m
95.8
79.5
57.5
77.8
513
603
620
578
8.1
6.1
5.7
6.6
18.0
9.0
6.3
11.1
B. blumeana
ISO22157
Thailand dry
MC 10.7%
(Sompoh et al.
2013), m
12.0
11.0
11.0
11.3
784
935
837
852
5.1
4.4
3.8
4.4
5.8
4.5
4.2
4.8
0.20
0.20
0.00
0.13
B, butt of culm; M, middle of culm; T, top of culm; m, mean of sample
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Table 4. Physical Properties of Other Bamboo Species According to ISO22157
Species, Country,
Source
Moisture Content
(%)
Relative Density
(kg/m3)
Shrinkage Wall
Thickness (%)
Shrinkage Outside
Diameter (mm)
Shrinkage Length
(mm)
B
M
T
All
B
M
T
All
B
M
T
All
B
M
T
All
B
M
T
All
G. angustifolia Kunth
Colombia
(Correal and Arbelaez
2010)
59.4
659
755
779
721
6.5
5.1
0.6
G. aculeata, Mexico
(Zaragoza-Hernandez et
al. 2015)
>FSP
560
560
660
593
15.5
15.9
10.2
13.9
8.1
7.8
5.5
7.1
0.1
0.1
0.1
0.1
G. amplexifolia, Mexico
(Ordonez-C. and
Barcenas-P. 2014)
164
140
116
140
427
476
546
483
G. velutina, Mexico
(Ordonez-C. and
Barcenas-P. 2014)
183
151
129
154
391
430
492
438
D. hamiltonii, Thailand
dry (Sompoh et al. 2013)
23.0
608
808
961
792
4.2
4.5
4.1
4.2
2.8
3.9
2.8
3.2
0.35
0.09
0.12
0.19
B. bambos, Thailand dry
(Sompoh et al. 2013)
18.7
856
799
804
820
8.5
7.7
6.0
7.4
7.6
7.0
5.8
6.8
0.14
0.15
0.20
0.16
D. asper, Thailand dry
(Sompoh et al. 2013)
11.3
748
773
779
767
4.5
6.5
2.2
4.4
4.3
5.4
3.9
4.5
0.1
0.0
0.0
0.03
P. pubescens dry China
(Deng et al. 2016)
8.0 to 12.0
669
723
770
721
B, butt of culm; M, middle of culm; T, top of culm; m, mean of sample
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Mechanical Properties
The mean compressive strength parallel to the grain was 36.4 MPa, and the
characteristic strength value 20.0 MPa, as documented in Table 5. The characteristic
compressive strength compares to the strength class C22 for sawn timber (EN338 2016).
The compressive strength increased from the butt toward the top of the culm, similarly to
the previously attested increase in density toward the top. The compressive strength
according to Espiloy (1992) was 16% higher, while Latif et al. (1992) found 26% lower
compressive strength of B. blumeana. The results of Espiloy (1992) and Latif et al. (1992),
stated in Table 8, remain difficult to compare to directly, as a merger of the Indian Standard
IS 6874 (1973) with a modification of the ASTM D143-94 standard (1994) as well as the
Indian Standard IS 6874 (1973) alone was applied for the Philippines and Malaysia,
respectively. The results highlight the importance of standardized testing procedures as
indicated in (Harries et al. 2012), to effectively identify variations among sourcing
locations. The compressive strength for G. angustifolia was comparable to B. blumeana
(Correal and Arbeláez 2010), while it was 15% higher than for G. aculeate (Zaragoza-hern
et al. 2015). In previous research, the compressive strength was attested to be most affected
by change in MC below the FSP (Xu et al. 2014). Testing of this study was conducted in
green condition, and results are therefore considered conservative.
For comparison to results of (Deng et al. 2016; Made Oka et al. 2014; and Somproh
et al. 2013) on bamboo species tested according to ISO 22157 in dry condition, reference
is given to studies on MC adjustment for G. angustifolia (Gutierrez et al. 2015) and P.
pubescens (Xu et al. 2014). However, MC adjustments are not yet standardized for B.
blumeana specifically and for bamboo engineering across different strength classes
generally; therefore this comparison is made with uncertainty and requires further research.
Results of the same species but air-dry samples of 12% MC by Somproh et al. (2013) were
83% higher than of this study. This increase is larger than MC adjustments identified for
other bamboo species. Xu et al. (2014) observed that the compressive strength of
P. pubescens specimen of air-dry samples was 33% higher than of that at its FSP (Xu et al.
2014). In Ordonez-Candelaria and Barcenas-Pazos (2014), an increase of 15% and 52% in
compressive strength was found for specimens of G. amplexifolia and G. velutina
comparing green and dry condition. For G. aculeate, an increase of 68% was attested by
Zaragoza-Hernandez et al. (2015). Comparing results tested in dry condition published for
Gigantochloa atroviolacea (G. atroviolacea) (Made Oka et al.) and P. pubescens (Deng et
al. 2016) to the current study, 42% and 51% higher results in compressive strength were
found respectively.
The delta is lower in comparison to the dry tested results for B. blumeana published
by Somproh et al. (2013). The wide range of MC adjustments between green and dry
condition across and within a species, documented in Table 9, highlights that more research
on MC adjustment for bamboo is needed. Testing in green condition facilitates
comparability for the meantime. A visualization of the compressive strength values is seen
in Fig. 2.
The mean tensile strength parallel to the grain was 162.3 MPa, and the characteristic
strength value 94.9 MPa. The internode tensile strength significantly increased from the
butt toward the top, with a p value of 0.01, whereas in the node the increase was not
significant. The increase of tensile strength in vertical direction toward the top can be
explained by a higher share of fibers toward the top, as discussed in the section of physical
properties above. The tensile strength at the node was lower than that at the internode.
According to Janssen (1980), the fibers in a node are interrupted by crossing vessels
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passing into the diaphragm inside the node. Because the mechanical elasticity is reduced
by the shorter, thicker, and forked fibers in the nodule, bamboo culms under tension often
break at the node (Liese 1974), which was confirmed by failure at the nodes of the tension
specimen of B. blumeana. In global comparison, results of tensile strength varied the most
across species with a range of 59 to 227 MPa, as documented in Table 9. The tensile testing
parallel to the grain with the wedge-shaped specimen caused also in the current study
problems with unintended failure mechanisms in shear, which was already indicated in ISO
22157-2 (2004). Consequently, these results caused by unintended failure mechanisms
were excluded. In Irawati et al. (2012) and Dela Cruz et al. (2017), alternative specimen
shapes were used that resulted in a higher rate of correct failures; these shapes thus appear
worthwhile for consideration in a revision of the standard. Further it was noted that several
previous studies did not include tensile strength testing in their publications, such as
(Correal and Arbeláez 2010; Ordonez-Candelaria and Barcenas-Pazos 2014; Deng et al.
2016). An improved test procedure with a higher rate of intended failures but no increase
of complexity for specimen production may incentivize researchers to include tensile
strength testing in their test agendas. In addition, it is noted that tensile strength
perpendicular to the grain is a largely ignored property of bamboo. However, it is critical
for structural performance. To date, perpendicular tension is not included in ISO 22157. In
(Sharma et al. 2013) and (Dela Cruz et al. 2017b), varying recommendations for its test
procedure were provided. Further research is recommended to form a baseline for a testing
protocol for inclusion in the standard.
The mean shear strength was 7.9 MPa, and the characteristic strength value was
5.1 MPa. The shear strength slightly increased toward the top with a p value of 0.05;
however, there was no significant difference between the middle and butt of the culm. The
latter was true for specimens with nodes and internodes. The existence of a node did not
lead to an increase of the shear or tensile strength but to rather lower results. This finding
is in line with previous reports (Made Oka et al. 2014). Compared to the current study,
(Latif et al. 1992) found 39% lower shear strength for B. bluemeana, while (Espiloy 1992)
did not assess it. Next to the variation of test procedures, also the sourcing location may
have caused the lower results. The variation observed between B. blumeana testing of this
research and that performed by Somproh et al. (2013) was in the expected range between
green and dry state as also reported by Xu et al. (2014) for P. pubescens with 55% and
51% increase, respectively. All results of B. blumeana are stated in Table 8. The results of
five other bamboo species tested in green condition ranged from 3.1 to 7.6 MPa. Test
results of nine bamboo species with specimen near or below the FSP and in dry conditions
ranged from 5.7 to 13.6 MPa. All results for other bamboo species are stated in Table 9.
According to the current study, the shear strength of B. blumeana is at the upper end of a
previously defined range for green specimen. It is noted that the shear strength calculation
assumes the development of four shear planes. However, the failure was mostly observed
in one of the planes. It is recommended to conduct tests on alternative specimen shapes for
shear strength that delivering failures in all the tested shear planes.
The mean bending strength was 62.8 MPa, and the characteristic strength value
34.6 MPa. The obtained bending strength values were characteristically high, reflecting the
flexibility of bamboo. Espiloy (1992) and Latif et al. (1992), found 14% lower and 77%
higher bending strength, respectively, as displayed in Table 8. Bending strength results
were specifically influenced by the variation in test standards, as three point bending tests
were applied before. The modulus of rupture increased from the butt towards the top of the
culm, which is explained by anatomical changes toward the top (Janssen 1980). The mean
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results of nine other bamboo species, tested in green and dry condition according to ISO
22157-1 (2004), ranged from 61 to 95 MPa. The mean B. blumeana results of the current
study were therefore at the lower end of the range, as documented in Table 9. Because of
the long internode distance of B. blumeana culms, the wooden saddle supports used for
testing the bending strength in the current study caused crushing failure in some specimens.
These results were consequently rejected from the assessment. The wooden saddles were
not always located above or below a node; however, this discrepancy from the ISO
recommendation could not be avoided because the symmetric distance between supporting
saddles had to be maintained. G. angustifolia was superior by approximately one-third in
terms of the bending strength (Correal and Arbeláez 2010). Bending testing with belts
instead of wooden saddles, as documented in the publication, may have contributed to
obtain higher bending strength results.
In summary, the characteristic strength values of B. blumeana were as follows:
compressive and tensile strengths parallel to the grain (fc,0,k = 20 MPa and ft,0,k = 95 MPa),
shear strength (fv,k = 5 MPa), and bending strength (fm,k = 34.6 MPa); in addition, the mean
MOE and the MOE at fifth percentile were Emean = 13100 MPa and E0.05 = 8600 MPa,
respectively. Tables 5 and 6 present the calculated characteristic strength of the current
study based on the raw data of B. blumeana. Table 7 provides a summary of the
characteristic strength values. The mechanical performance of B. blumeana can be
considered suitable for structural application in low-rise housing. The compressive and
tensile strength along the grain and bending strength of B. blumeana demonstrate the
potential of bamboo for construction. Construction methods must be found, which consider
the low shear strength of bamboo culms especially in connections (Latif et al. 1992).
Table 8 shows the mechanical properties of previous studies on B. blumeana, with other
sourcing locations and test standards or test conditions. Table 9 documents the mechanical
properties published for other bamboo species according to ISO 22157-1 (2004). Overall,
the performance of B. blumeana was in the expected range of results of previous studies
on full bamboo culms used for structural purpose. Figure 2 visualizes selected mechanical
properties of various bamboo species, including B. blumeana.
Fig. 2. Mechanical Properties of various bamboo species, including B. blumeana, in [N/mm2]
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Table 5. Strength Properties of B. blumeana
Property
Compressive Strength
Parallel to the Grain
(N/mm2)
Tensile Strength
Parallel to the Grain
(N/mm2)
Bending Strength
MOR
(N/mm2)
Modulus of Elasticity
(Bending)
MOE (1000 N/mm2)
Position
B
M
T
All
B
M
T
All
B
M
T
All
B
M
T
All
m
31.2
37.4
40.6
36.4
126.5
174.1
187.6
162.3
56.7
62.5
69.0
62.8
11.7
14.1
13.5
13.1
s
6.9
9.0
5.4
8.0
22.1
33.1
45.7
43.2
16.1
19.9
14.5
17.2
2.0
4.3
3.7
3.5
f0.05
22.0
24.7
34.0
22.5
101
127.5
128.3
104.7
39.9
39.9
52.5
39.9
9.1
7.7
8.6
8.6
n
10
10
10
30
20
20
19
59
10
10
10
30
10
10
10
30
fk
17.8
19.6
30.1
20.0
90.3
112.9
108.9
94.9
30.2
29.1
43.1
34.6
7.7
5.7
6.5
7.4
B, butt of culm; M, middle of culm; T, top of culm; m, mean of sample; s, standard deviation; f0.05, 5th percentile value of the sample (N/mm2); n, size of
sample; fk, characteristic value (N/mm2);
Table 6. Shear Strength at Nodes and Internodes
Property
Shear Strength Parallel to the Grain (N/mm2)
Position
B
M
T
All
Node
Internode
Node
Internode
Node
Internode
m
7.1
6.9
7.4
8.1
8.8
9.4
7.9
s
0.8
1.1
1.9
1.5
1.6
1.7
1.7
f0.05
6.1
5.5
5.4
6.0
6.8
7.2
5.5
n
10
10
10
10
10
10
60
fk
5.4
4.7
4.2
5.1
5.8
6.1
5.1
m, mean of sample; s, standard deviation; f0.05, 5th percentile value of the sample (N/mm2); n, size of sample; fk, characteristic value (N/mm2)
Table 7. Summary of Characteristic Strength Values for B. blumeana
Property
Symbol
Characteristic Strength
Compression strength parallel to grain
fc,0,k
20 MPa
Bending strength
fm,k
34.6 MPa
Shear strength
fv,k
5 MPa
Tension strength parallel to grain
ft,0,k
95 MPa
Modulus of elasticity - mean
Emean
13.1 GPa
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Table 8. Previous Mechanical Properties of B. blumeana According to Other Test Standards or Test Conditions with Varying
Sourcing Regions
Compressive
strength
parallel to the
grain
(N/mm2)
Tensile
strength
parallel to the
grain
(N/mm2)
Shear
strength
parallel to the
grain
(N/mm2)
Modulus of
elasticity
bending
(1000
N/mm2)
Bending
strength
MOR
(N/mm2)
B. blumeana Philippines IS6874 (1973) & ASTM D143 (1994)
(Espiloy 1992)
42.2
10.2
54.2
B. blumeana Malaysia IS6874 (1973) (Latif et al. 1992)
27.1
4.8
110.9
B. blumeana ISO22157 Thailand MC 10.7% (Sompoh et al. 2013)
66.5
253.8
12.3
92.0
Table 9. Previous Mechanical Properties of Other Bamboo Species According to ISO22157
Compressive
strength
parallel to the
grain
(N/mm2)
Tensile
strength
parallel to the
grain
(N/mm2)
Shear
strength
parallel to the
grain
(N/mm2)
Modulus of
elasticity
bending
(1000
N/mm2)
Bending
strength
MOR
(N/mm2)
>FSP
dry
>FSP
dry
>FSP
dry
G. angustifolia Kunth Colombia (Correal and Arbelaez 2010)
38.9
7.6
17.4
94.8
G. aculeata Mexico (Zaragoza-Hernandez et al. 2015)
30.8
51.8
71.5
6.7
8.3
16.8
61.1
G. amplexifiolia Mexico (Ordonez-C. and Barcenas-P. 2014)
29.2
33.5
4.4
5.8
18.5
90.0
G. velutina Mexico (Ordonez-C. and Barcenas-P. 2014)
24.4
36.9
4.3
5.7
17.4
82.8
D. hamiltonii Thailand (Sompoh et al. 2013) MC 23%
50.8
58.7
7.5
81.4
B. bambos Thailand (Sompoh et al. 2013) MC 19%
54.3
131.3
6.4
78.7
D. asper dry Thailand (Sompoh et al. 2013) MC 11%
68.7
227.2
9.4
83.7
G. atroviolacea Indonesia (Made Oka et al. 2014) MC 13-15%
51.6
182.1
7.7
P. pubescens China (Deng et al. 2016) dry MC 8-12%
54.8
13.6
P. pubescens (Xu et al. 2014)
32.8
45.4
7.0
10.6
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Recommendations
Table 10 presents the characteristic strength values for B. blumeana. In accordance
with the state design principles, the permissible stresses for using B. blumeana in low-rise
construction in the Philippines were derived by dividing by the safety factors.
Table 10. Summary of Characteristic Strength and Suggested Permissible
Stresses for B. blumeana Bamboo
Property
Characteristic Strength
Permissible Stress
Symbol
Value
Symbol
Value
Compression Strength Parallel to
Grain
fc,0,k
20 MPa
fc,0,adm
8.0 MPa
Bending Strength
fm,k
34.6 MPa
fm,adm
7.7 MPa
Shear Strength
fv,k
5 MPa
fv,adm
1.1 MPa
Tension Strength Parallel to Grain
ft,0,k
95 MPa
ft,0,adm
21 MPa
Modulus of Elasticity - Mean
Emean
13.1 GPa
Emean
13.1 GPa
Modulus of Elasticity - 5th Percentile
E0,05
7.4 GPa
Emin
7.4 GPa
Density - Mean
mean
570 kg/m3
mean
570 kg/m3
Given the natural variability of bamboo, conservative safety factors are
recommended. A safety factor of 4.5 is considered for permanent loads, which is in line
with ISO 22156 (2004) and conservative compared with Eurocode 5 EN 1995-1-1 (2004).
The latter can be reduced for loads that last for short durations.
Utilization of Test Results
The suggested permissible stresses stated in this work are only applicable for
construction for quality-controlled, mature B. blumeana bamboo culms from the
Philippines. The physical and mechanical properties reported here are only a step toward a
more widespread application of bamboo for house construction. Further sourcing regions
of the same species or additional bamboo species may be tested in its addition according
to ISO22157 (2004) and ISO 22156 (2004). For strategic utilization and entry of bamboo
into the low-rise building sector in the Philippines, studies on high-performing, cost-
efficient bamboo-based construction systems must be performed. Building methods can
use the favorable compressive, tensile and bending strength of bamboo culms, while their
weakness in shear strength needs consideration, especially for connection design
transferring the loads reliably during the entire lifespan of the houses. An example of such
a study from Colombia is that of Lopez Munoz (2000). To facilitate larger scale use of a
bamboo species in construction, a strength grading as described by (Trujillo 2017) for G.
angustifolia Kunth may be implemented to simplify the selection of culms for structural
purpose in the Philippines through a rapid selection process. Further, the use of bamboo in
construction requires treatment and protection by design as a prerequisite because
degradation would otherwise limit its lifespan. Negative implications of insufficient
protection against aging have been confirmed both through accelerated laboratory testing
(Huang et al. 2014) and long-term studies with exposure to outdoor applications (Cardona
et al. 2002; Beraldo 2016).
The physical and mechanical properties for B. blumeana stated in this paper can
contribute to address bamboo-based housing in the Philippines holistically. This research
PEER-REVIEWED ARTICLE bioresources.com
Salzer et al. (2018). “Bamboo housing properties,” BioResources 13(1), 346-369. 364
informs a participatory, South-South knowledge exchange between Colombia and the
Philippines on bamboo-based building. The latter enables an effective, accelerated learning
curve to meet multi-stakeholder needs of social housing in the Philippines and elsewhere,
while it highlights the importance of local participation, context adaptation and placing
people’s needs at the center (Base Builds 2015). Next to the characterization of the species,
consideration is given to the use-phase of bamboo-based houses, including its durability
and maintenance efforts; flexibility for upgrading and expansion; performance under
extreme impact events such as fire, earthquakes, or intense winds; and thermal comfort.
Through open development and multi-stakeholder feedback loops, science and technology
can inform communities, policy makers, professionals and further stakeholder groups
effectively. Forming multi-stakeholder partnerships is essential to address the tremendous
challenge of social housing in an urban century (UN-ESCAP and UN-Habitat 2011).
CONCLUSIONS
1. This paper elucidates the structural qualities of B. blumeana bamboo sourced from a
characteristic bamboo growing region of the Philippines. The species exhibited
properties of structural quality, and it is generally recommended and suitable for use in
low-rise construction. Characteristic strength values were computed based on the test
results. A recommendation for permissible stresses was made, which can serve in
structural design when using the bamboo species for the construction of low-rise
houses. The results of this work are only applicable for construction when the bamboo
culms are being quality-controlled and embedded in a suitable building method.
2. The physical and mechanical properties of B. blumeana were in the same range as other
species around the world, which are used for structural purpose in their full culm such
as G. angustifolia Kunth, G. aculeata, D. asper, G. atroviolacea, and P. pubescens.
3. The standardized assessment of physical and mechanical properties according to
ISO22157-1, ISO22157-2, and ISO22156 is recommended for full culm
characterization of B. blumeana sourced from further locations in the Philippines and
Asia-Pacific as well as for further bamboo species around the world. It enables
comparability among different regions, test dates, and species. Testing in green
condition will facilitate comparability. An update of the ISO standards is
recommended, based on available tests results suggesting the revision of existing or the
inclusion of additional test protocols.
4. The present research is a starting point to further research and application, higher
acceptance and collaboration. For durable results, an effective bamboo treatment and
protection by design is required. Research on the use-phase of bamboo-based houses is
recommended, tackling the requirements of stakeholder groups in urban social housing.
Sustainable harvesting practices are important, to ensure sustainability of using the
species in the long term. For an effective use of the test results, participatory
application, multi-stakeholder partnerships as well as regional and global knowledge
exchanges are recommended.
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Salzer et al. (2018). “Bamboo housing properties,” BioResources 13(1), 346-369. 365
ACKNOWLEDGMENTS
The authors thank the Hilti Foundation for funding this research. The authors also
acknowledge the Chalmers Area of the Advance Built Environment profile “Responsible
Use of Resources”, which supports affordable building-related research. The authors
appreciate the contribution of Bambou Science et Innovation and Fundeguadua
triangulating test procedures and acknowledge the Forest Products Research and
Development Laboratory Los Banos Philippines, where the testing was conducted. Finally,
the authors thank Tiffany Jain, M.S., from Edanz Group for English editing a draft of this
manuscript.
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DOI: 10.15376/biores.13.1.346-369
... Another factor that significantly influences the values of biomechanical parameters of plants from the grass family Poaceae (in this case miscanthus) is the internode from which the samples for strength tests are taken. Different internodes of the same stalk have different values of biomechanical parameters [40,44,48,49,[57][58][59][60][61]. ...
... The following equation was used to determine the moisture content [42,57,58,60,[68][69][70]: ...
... The next step was to calculate the load capacity of the stalk, expressed as the maximum stress, corresponding to the destruction of the test sample during the compres-sion test ( Figure 4). The value of the bearing capacity was determined from the equation [57,60,65,[68][69][70][71][72][73][74]: ...
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So far, there are no results for research on the biomechanical parameters of giant miscanthus stalks taking into account both the influence of moisture content and the internode, from which the samples were taken. Therefore, the aim of the research was to comprehensively investigate the influence of the internode number (NrNod) and water content (MC) on the values of selected biomechanical parameters (modulus of elasticity and maximum stress) determined using various stress tests (three-point bending and compression along the fibers). The research was carried out for dry stalks of different humidities and for different internodes. The results obtained in this study proved that the independent variables of the water content and the internode number cause a statistically significant influence on the values of the examined biomechanical parameters of the miscanthus stem: the modulus of elasticity in compression, the maximum stress in compression, the modulus of elasticity in bending and the maximum stress in bending. The values of the modulus of elasticity (MOE) increase when increasing the NrNod. For individual internodes, MOE values are higher with a higher MC. The values of the maximum stress (σ) also increase when increasing the internode number. For individual internodes, the σ values are lower with a higher MC.
... Numerical analysis of load-bearing bamboo beams during fire. ................................................. 161 7 (Lynch, 2016), and round bamboo structure in Indonesia (right) (Ibuku, 2017) Figure 5.45 Mid-span deflection against time in beams loaded at 4, 6 and 8 kN, and exposed to a Tables Table 2.1 Bamboo species commonly used in the construction industry worldwide a (Correal, 2016), b (Trujillo & López, 2016), c (Luna, Lozano, & Takeuchi, 2014), d (Salzer et al., 2017), e (Surjokusumo & Nugroho, 1995 & Janssen, 2006a). Bamboo has one of the highest renewable rates in nature, and it is exceptionally high when compared with other natural construction materials like timber (Vogtlander & Van der Lugt, 2014). ...
... The fabrication of load-bearing structural systems using round bamboo has historically been shown to yield a low economic and temporal cost (Kaminski, Lawrence, Coates, et al., 2016;Salzer, Wallbaum, Alipon, & Lopez, 2017;Sassu, De Falco, Giresini, & Puppio, 2016). In recent years, engineered bamboo products, laminated from strips of bamboo, have emerged allowing the fabrication of load-bearing elements with regular cross-sections and less dispersion of mechanical properties (Sharma, Bauer, Schickhofer, & Ramage, 2017). ...
... Values of specific strength and specific stiffness (strength and elastic modulus normalised by density) are higher than many other conventional materials (natural or synthetic) as wood, steel and concrete (Wegst et al., 2015). (Correal, 2016), b (Trujillo & López, 2016), c (Luna, Lozano, & Takeuchi, 2014), d (Salzer et al., 2017), e (Surjokusumo & Nugroho, 1995). ...
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The remarkable high strength-to-weight ratio of bamboo and the recent innovations and development of laminated bamboo products has enabled the potential for new larger and taller structural bamboo applications. However, there is little understanding of the behaviour and performance of bamboo structures during and after a fire. To date, bamboo has been used widely in low-rise constructions where structural integrity during and after a fire does not pose a risk to the life safety of occupants, fire service intervention, and significant impact to property protection or business continuity. Nevertheless, a comprehensive understanding of the structural fire performance is crucial if bamboo is to be widely used in the construction of mid- and high-rise load-bearing structures. An extensive literature review on the fire performance of bamboo structures shown herein identifies that novel fire testing methods were needed to investigate the mechanical response of bamboo, primarily to study the reduction in the strength and stiffness at elevated temperatures. Past research outcomes have evidenced the need for constitutive stress-strain models to describe the mechanical behaviour of bamboo at elevated temperatures, as well as numerical models to predict the response of the bamboo load-bearing members during and after a fire. Several small and bench-scale experimental studies were conducted to understand the reduction in the mechanical properties of bamboo at elevated temperatures. Compressive tests were performed for round and laminated bamboo for test samples at temperatures between ambient and 250ºC. Another set of experiments was performed in laminated bamboo samples to see the response in compression after heating and cooling. Round bamboo strips were tested in tension to understand the reduction in the tensile strength at elevated temperatures. The modulus of elasticity was obtained for all bench-scale experiments to quantify the reduction in stiffness due to high temperature. A dynamic mechanical analysis of bamboo strips was carried out to investigate the decrease in the modulus of elasticity at elevated temperatures, and to compare this against the results of bench-scale tests to analyse the effect of a different test set-up and heat transfer scenario. With the experimental results of the reduction of the compressive and tensile strength of bamboo, as well as the modulus of elasticity, constitutive stress-strain models were proposed to correlate the stress-and strain relationship at elevated temperatures. Equations for the reduction factors of strength and modulus of elasticity were presented, as well as stress-strain curves. The linear elastic behaviour of bamboo under tension and compression, and the elastoplastic behaviour under compression were analysed to quantify the effects of elevated temperatures. Another series of experiments were conducted to investigate the performance of laminated bamboo beams exposed to fire. The bamboo beams were loaded at different stress-levels whilst exposed to a constant indecent heat flux. The beams were fully instrumented to measure the loss of cross-section, the strain profiles, and the deflections at the mid-span during the heating exposure. Detailed results of the experimental tests showing the effects of simultaneous loading and heating in laminated bamboo beams are presented in this document. Finally, a numerical model combining the thermal performance, and the mechanical behaviour of bamboo at elevated temperatures was developed to predict the stress-strain profiles, the deflection, and the bending capacity of bamboo beams during a fire. The results of the numerical model were compared against the results obtained from the experimental tests, and the model showed a good agreement with the experimental results. The proposed framework shows that structural analysis can be carried out if heat transfer analysis and constitutive stress-strain models are available to predict the thermo-mechanical response of laminated bamboo beams. Findings from this work provide a good understanding of the reduction on the strength and elasticity of bamboo at elevated temperatures. These results will enable predictions to be made for the bending capacity of bamboo beams during a fire, and they will constitute the basis for designing fire-safe bamboo structures.
... This characteristic has not been reported for Phyllostachys edulis (Amada et al. 1996), Guadua angustifolia or Bambusa stenostachya (Harries et al 2016), and not significantly visible in the species studied by Shigematsu (1958). However, Salzer et al. (2018) does report larger diameters in the middle of the culm, than at the base, which suggests this may be a peculiarity of the species. ...
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ISO 19624:2018 is the world’s first international bamboo grading standard. It contains few prescriptive clauses and is mostly written as a recipe for a national grading standard. This paper reports the initial phases of the implementation of this standard in the context of a production plant (Kawayan Collective) exploiting Bambusa blumeana harvested in The Philippines. The team undertook the initial evaluation (i.e. characterization) of B. blumeana harvested from six sites. 123 culms were geometrically and mechanically characterised, as required by ISO 19624. Current visual grading rules used at Kawayan Collective have been recorded as well as their associated rejection rates and resulting associated cost of this rejection. Early findings from the initial evaluation are discussed.
... Moreover, In order to take action to fight climate change it is necessary to promote the use of alternative construction materials especially those based on biomaterials. Bamboo is considered one of the fasted growing plants and it is wide idly available in the regions where the housing demand is the highest [1]. ...
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The provision of sustainable housing solutions is one of the main challenges in emerging economy countries. Furthermore, it is clear that a sustainable solution should be based on renewable bio-based materials. The scientific and practical evidence clearly suggests that the use of bamboo in the provision of housing solutions not only brings environmental but also socioeconomic benefits to the communities using these strategies. One barrier to the promotion of this type of solution is the lack of knowledge for its structural design and environmental performance. Moreover, the access to assessment tools and methodologies to carry out such assessments is limited. Life Cycle Assessment (LCA) is widely recognized as the most appropriate method to calculate environmental impacts through a product's life cycle. LCA is methodologically described on the ISO series 14040 and proposes an input-output relationship between the environment and human activity. LCA has been used in research with many case studies focusing on the built environment and especially on buildings. Nevertheless, the practical application of LCA is very limited, especially in the affordable housing sector. Two main reasons had been identified, first the development of LCAs is data and time intensive and second the cost of software or third-party assessment makes the implementation of LCA on affordable housing projects unviable. The use of simplified LCA has shown great potential to solve these challenges but the generation of life cycle inventory data remains a main issue hindering its implementation of user-friendly tools. On this paper, we describe the development of a methodological approach to use parametric design to generate the data required to carry out simplified life cycle assessment of bamboo-based buildings. Moreover, we present a case study assessing a housing unit using cement-bamboo frame technology developed by the NGO Base-Bahay in the Philippines. From these experiences, it can be concluded that parametric design is a valid approach to overcome the main identified challenges. In addition, this approach requires further development to cover additional design features like wind, earthquake, and soil quality demands. With this work, we show that the complexity of LCA can be reduced. Finally, the use of parametric approaches enables the development of cost-effective solutions that can increase access to this kind of assessment in the affordable housing sector.
Conference Paper
Plywood is the glued of vernier layers. In construction, it is usually used to make parts of restriction in the home or building. The thickness of plywood between 3mm to 32mm and marketed in two sizes that 91cm x 183cm and 122cm x 244cm. Bamboo is a type of plant that is unique for its fast growth. Bamboo grows up faster comparing to any other kind of wood resource and also lighter in weight. It also has a great strength which can withstand high pressure due to any kind of loads and can maintain for a long time efficiently. Using bamboo will get more beautiful artwork and attract people. Moreover, bamboo is easily found and has a reasonable price compared to timber and others. The purpose of this project is to design and produce the model of the rest house using the laminated bamboo and also to determine the mechanical properties of the bamboo which is safe and suitable to be used. The main materials that had been used to build the model are Dendrocalamus Asper which is also known as Buluh Betung. It is cut into pieces and combined together to form a laminated bamboo. Laminated bamboo has been used in every part of the model, including walls, roof, truss, and floor. Mechanic properties of laminated bamboo had undergone three tests which were compressive, tensile, and bending test according to the standards of BS EN (British and European Standard). All of these tests were conducted to know the flexibility and strength of the laminated bamboo.
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The growing demand for sustainable load-bearing materials drives the need for understanding the various design considerations these pose within the modern built environment. Engineered bamboo is a material with outstanding physical and mechanical properties, in addition to producing a minimum carbon footprint. However, extensive research is needed before engineered bamboo can be used with the confidence conferred to other more conventional building construction materials. When aiming for higher and larger bamboo-based structures, load-bearing behaviour during and after fire becomes a key consideration. This paper describes the outcomes of a comprehensive study conducted to understand the mechanical behaviour of bamboo (Phyllostachys pubescens species) at elevated temperatures; more specifically investigating the reduction of compressive and tensile strength, as well as the Modulus of Elasticity (MoE) up to 250 °C. Findings from this work show that at 200 °C, bamboo retains 20%, 42% and 70% of the compressive strength, tensile strength and modulus of elasticity at ambient, respectively. The results presented herein, which provide thorough understanding of strength and elasticity reduction at elevated temperatures, enable the development of stress-strain constitutive models that will constitute the basis for designing fire-safe bamboo structures.
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The bamboo specie Bambusa Tuldoides, although abundant throughout Brazil, is not used for the production of structures. Therefore, conducting tests for the mechanical characterization of this specie is important for its use in constructions to be diffused. In this way, the present work presents the procedures for the determination of some physical-mechanical properties of this species. Results were found for basic density in the order of 931 kg / m3, mean static flexural stress of 155 N / mm², static flexural modulus of 34113 N / mm², parallel shear of 1.2 N / mm², and compression parallel between 43.3 and 89.9 N / mm². 1 Introdução A demanda por materiais de construção sustentáveis cujos processos fabris utilização na obra e descarte final sejam o menos impactante o possível ao meio ambiente, tem aumentado significativamente em todo mundo. Deste modo, o bambu se apresenta como uma alternativa importante, pois, além de apresentar características físico mecânicas compatíveis com os principais materiais disponíveis para a produção de estruturas, (Ghavami,1988), tais como o aço, concreto e alumínio, é renovável e de baixo custo. O bambu possui muitas características que o coloca como um material sustentável de grande importância para o suprimento do déficit habitacional no mundo. Além de possuir elevada resistência físico mecânica (Ghavami, 1981) pode ser encontrado em grande parte do planeta (Lopez, 1978). Uma touceira de bambu pode durar acima de 50 anos produzindo anualmente colmos que podem ser destinados aos mais diversos usos, desde a alimentação até a construção civil, do paisagismo à medicina (Beraldo 1992).
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Purpose The environmental impact of the social building stock is relevant, particularly in emerging economies. Life cycle thinking is not yet established, however. Locally available, alternative building concepts could potentially reduce the environmental impact of the construction segment. This paper examines the environmental performance of “as-built” low-cost housing for an example of the Philippines, and the potential to reduce its environmental impact through use of three alternative building technologies: cement–bamboo frames, soil–cement blocks, and coconut board-based housing. Methods Life cycle assessment models are implemented and evaluated with software SimaPro, using the single-impact indicators global warming potential (GWP) and cumulative energy demand (CED) and the multi-impact indicator Impact2002+. According to EN 15978, the life cycle phase product and construction process (A), use stage (B), end-of-life (C) and supplementary information beyond the building life cycle (D) have been assessed. Theoretically calculated inflows from standard construction procedures used in phase A have been verified with 3 years of empirical data from implemented construction projects. For phases B, C and D, attention was given to service life, use-phase, allocation of waste products, biogenic carbon and land-use assumptions. Scenarios reflect the actual situation in the emerging economy. Processes, such as heat recovery from thermal utilization, which are not existing nor near to implementation, were excluded. Results and discussion For an assessment of the phases A–B–C–D with GWP, a 35% reduction of environmental impact for soil–cement blocks, 74% for cement–bamboo frame, and 83% for coconut board-based houses is obtained relative to a concrete reference house. In absolute terms, this relates to a reduction of 4.4, 9.3, and 10.3 t CO2 equivalents over a service life of 25 years. CED showed higher impacts for the biogenic construction methods coconut board and cement–bamboo frames of +8.0 and +4.7%, while the soil–cement technology was evaluated −7.1% compared to GWP. Sixteen of 17 midpoint categories of Impact2002+ confirmed an overall reduction potential of the alternative building methods, with the midpoint category land occupation being the exception rating the conventional practice over the alternatives. Conclusions It is concluded that the alternative construction technologies have substantial potential to reduce the environmental burden caused by the social housing sector. The service life of the alternative technologies plays a vital role for it. LCA for emerging economies needs to incorporate realistic scenarios applicable at their current state or belonging to the most probable alternatives to ensure valuable results. Recommendations for further research are provided.
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The study was conducted to determine the physical and mechanical properties for house construction of five bamboo species: Pai Hok (Dendrocalamus hamiltonii Nees et Arn. Ex Munro), Pai Pa (Bambusa bambos (L) Voss), Pai Ruak Yai (Thyrsostachys oliveri Gamble), Pai Ruak Lek (Thyrsostachys siamensis Gamble), and Pai Lammalok (Dendrocalamus longispathus Kurz), harvested from Maehongson and Kanchanaburi Provinces. The highest shrinkage and fiber saturation point were found in B. bambos. This bamboo species also exhibited the highest static bending strength followed by T. siamensis, T. oliveri, D. longispathus and D. hamiltonii. The mechanical properties of these five bamboo species were found to be at about the same level compared to those exhibited in the previous studies, as well as to some hardwoods such as Dipterocarps. Therefore, these five bamboo species could be used as a general utility timber for housing components due to their culm form and the bending properties.
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Conference Paper
Due to the current need to find alternative materials that generate less environmental impact, in recent decades, the bamboo guadua Angustifolia Kunth has been positioning in Colombia as an excellent material for structural use, thanks to the excellent physical and mechanical properties that have been demonstrated in many investigations and in the performance of many structures to seismic events occurred in the past. In 2010 the guadua Angustifolia Kunth was included in the Colombian seismic-resistant building code of 2010 (NSR 10), specifically in Title G, called " Timber and bamboo guadua structures " , however, Nowadays many of the data required for making a structural design in this material have not yet defined or well known. One of those unknown parameters corresponds to the fiber saturation point (FSP), a value of great importance to know the variation in strength and stiffness due the variation in the moisture content of the material. It has been found that when this specific moisture content is reached, the material does not show dimensional changes in its structure and it won't have a considerable variation in the mechanical compression strength parallel to the fiber. During a specific time the moisture content has been modified in order to find the moisture content range at which the study material will present a volumetric stability. It was found that the FSP for both methodologies was 34% ± 3%, and 32% ± 3%, respectively. These values will allow determining an approximate range in which the fiber saturation point is located. With that information it will be possible to validate the data contained in the NSR-10, specifically the Table G.12.7-5, regarding modification coefficients by moisture content.
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Conference Paper
Bamboo is one of the raw materials exhibiting the greatest potential for construction applications, especially in rural areas. According to its physical and mechanical properties, several species of bamboo can be employed in building elements design. In order to verify the material performance, in the year 1999, on the campus of the Unicamp, it was designed and built an experimental house employing several bamboo species as Dendrocalamus asper (columns and beams), Guadua angustifolia (beams), Bambusa tuldoides as well as Bambusa vulgaris (walls) and Phyllostachys aurea (windows, door and closing). In addition, the protective sidewalk and undulated tiles were made from mixtures of plant biomass and Portland cement mortar (Biokreto®). In the structure they were employed G. angustifolia stems; D. asper columns were treated in 5% solution of chromated copper borate (CCB). Walls of bahareque from B. tuldoides splits were protected by Portland cement and sand mortar, modified by sugar cane bagasse fibers addition. Windows and doors were made from natural P. aurea culms recovered by polymer. Sidewalk and undulated tiles were made of Portland cement and sand mortar, reinforced with bamboo particles and rice husk, respectively. Past 17 years, the housing components were evaluated by visual aspects. It was observed that D. asper columns have been completely destroyed by termites; due to the fungi´s action the aerial structure of D. asper crushed. Wall of bahareque from B. tuldoides and B. vulgaris showed black spots only at the bottom and they supported the roof loads due to horizontal steel reinforcement. Windows and doors were damaged due to cracks generated in the polymer matrix. As a positive aspect, sidewalk and undulated tiles did not decay.
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Wet chemical analysis was used to determine carbohydrate structural contents, as well as ash and extractive contents on four Guadua Angustifolia Kunth forms (f. Cebolla, f. Macana, f. Rayada Amarilla and f. Castilla) with two different growth ages (young and mature). Soluble and insoluble fiber content was determined by using AOAC 985.29 method. Bending tests were conducted in a universal testing machine following ASTM D143 standard method in order to determine modulus of rupture (MOR). Finally, a correlation between contents of chemical compounds and bending behavior (MOR modulus) was carried out with SPSS Statistical Package, version 7.0, obtaining Pearson's coefficient correlation and showing the relationship between soluble fibers and bending response for mature Guadua culms.
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As an abundant natural resource in Asia, bamboo is receiving increased attention as an engineering material due to its renewability and excellent strength. The parallel-to-grain compression and shearing properties of moso bamboo culm were examined. The growth characteristics (bamboo age, nodes, and location along the culm), as well as treatments for practical applications (hole punching and hoop reinforcing by hose clamp) were investigated for their influence. Mechanical tests were conducted in accordance with the ISO22157-1: 2004 (2004), ISO/TR 22157-2:2004(E) (2004), and CNS GB/T 15780-1995 (1996) standards. Acceptable loading rates for the parallel-to-grain compression and shearing tests were 0.1 and 0.05 mm/s, respectively. The compressive and shearing strengths increased from the bottom to the top of the bamboo. Bamboo age and nodes exerted little influence on parallel-to-grain compressive and shearing strength. In addition, hole punches diminished the mechanical strength of the bamboo culm, while hose clamps enhanced it slightly.
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The physical and mechanical properties of Guadua aculeata culm are shown in this paper. The study material was collected from the locality "Las Margaritas" Hueytamalco, Puebla, Mexico. The marking, felling and testing was performed with reference to ISO standards ISO 22157-1 and ISO/TR 22157-2. The average values of the results of low, middle and upper sections are shown; the basic density (dry weight / green volume) ranged from 560 to 660 kg/m(3) of the lower to upper culm section. The average total contractions were 13,9% in thickness; 7,1% in diameter and 0,1% in length. In the case of mechanical properties were found that the maximum shear stress varies from 6,0 to 10,5 MPa; the maximum stress in compression parallel to fiber increased from 28,2 to 56,7 MPa from low to top section and the modulus of elasticity from 13,7 to 20,7 GPa. The modulus of rupture in bending varies from 51,9 to 79,6 MPa and the modulus of elasticity from 15,1 to 24,1 GPa. The strength in tension parallel to the fiber also increased from 58,5 to 92,2 MPa and modulus of elasticity ranged from 8,2 to 9,8 GPa. The studied specie has the same physical, mechanical and geometric properties to G. angustifolia that it is used in the construction in countries how Colombia, Costa Rica, Panama, Venezuela and Ecuador.
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The moisture dependence of different mechanical properties of bamboo has not been fully understood. In this work, the longitudinal tensile modulus, bending modulus, and compressive and shearing strength parallel to the grain were determined for bamboo of ages 0.5, 1.5, 2.5, and 4.5 years under different moisture contents (MC) to elucidate the sensitivity of different mechanical properties of bamboo to MC change. The results showed that the four mechanical properties of bamboo respond differently to MC changes. Compressive and shearing strength parallel to the grain were most sensitive to MC changes, followed by longitudinal tensile modulus, then bending modulus. This can be partially explained by the different responses of the three main components in the plant cell wall to MC change. For tensile modulus and bending modulus, the effect of bamboo age on the sensitivity to MC change was insignificant, while young bamboo (0.5 years old) was more sensitive to MC changes for shear strength and less sensitive for compression strength than older bamboo.
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Bamboo is a giant grass and not a tree. Bamboo completes its growth within some months and matures at the age of around three years, there is no secondary growth. Moisture content of bamboo varies along its height location and with seasoning period, which affects all physical and mechanical properties. It is one of the important factors in deciding the life of bamboo. This paper presents results of experimental investigations made to evaluate the physical and mechanical properties of the bamboo species Dendrocalamus strictus and its utilization potential as building material may be as whole or in the split form. In the present study moisture content, specific gravity, water absorption, dimensional changes, tensile and compressive strength at different height location are worked out. The moisture content varies along the height for green bamboo or at any time after harvesting. The top portions had consistently lower moisture content than the middle or basal at all stages of seasoning. Specific gravity on oven dry mass basis decreases from top to bottom and is independent of moisture content. Water absorption is inversely proportional while dimensional changes, tensile and compressive strength are directly proportionate to moisture content.