structural behavior of glued laminated guadua bamboo as

STRUCTURAL BEHAVIOR OF GLUED LAMINATED GUADUA 

BAMBOO AS A CONSTRUCTION MATERIAL 

Juan Correal 1 , Fernando Ramirez 2 , Soffy Gonzalez 3 , Jessica Camacho 4 

ABSTRACT: Currently, there is a global need to have sustainable materials in order to ensure resources for present and 

future generations. Besides timber, bamboo can be an interesting sustainable material since it has high strength to 

weight ratio, relative low cost and fast growing rate. According to the International Network for Bamboo and Rattan, 

there are about 1.250 species of bamboo all over the world but only 20 of them are considered suitable for construction. 

A giant specie of bamboo called Guadua Angustifolia kunt has been used as a construction material in Colombia for 

more than 20 years. Even though, round guadua has been used in construction of structures with relative success, one of 

the problems is the variability of its geometry, mechanical properties and anatomical composition that makes this 

material difficult to characterize and prevents its use in large structures. Glued Laminated Guadua Bamboo (GLG) is 

considered as an excellent alternative; since few exploratory studies indicated that it has mechanical properties are as 

good as the best structural woods in Colombia. 

The Universidad de los Andes in Bogotá, Colombia is developing a comprehensive study about the performance of 

GLG as a structural material. Due to the lack of research on mechanical behavior of adhesives on GLG, the present 

study was focused first on determine the best type of adhesive as well as its optimum amount. Once this stage of 

research was done, a detail mechanical and physical characterization was performed. Finally, the mechanical properties 

of GLG are compared to Andean structural woods. 

KEYWORDS: Bamboo, Glued Laminated Guadua, Mechanical Properties, Physical Properties. 

1 INTRODUCTION 1234 

Bamboo is a group of woody plants that belong to the 

grass Poaceae family and Bambusoideae subfamily. The 

giant bamboo is the largest member of the grass family 

and according to Liese [1] this is the fastest growing 

plant in the world. The rate of growing varies between 

1 Juan F. Correal, Director of Integrated Lab and Assistant 

Professor of Civil and Environmental Engineering Dept., 

Universidad de Los Andes, Bogotá, Colombia, Cra. 1 Este # 

19A-40. Email: jcorreal@uniandes.edu.co. 

2 Fernando Ramirez, Associate Professor of Civil and 

Environmental Engineering Dept., Universidad de Los Andes, 

Bogotá, Colombia, Cra. 1 Este # 19A-40. Email: 

framirez@uniandes.edu.co. 

3 Soffy Gonzalez, Graduate Assistant of Civil and 



sj.gonzalez41@uniandes.edu.co. 

4 Jessica Camacho, Undergraduate Assistant of Civil and 



jf.camacho49@uniandes.edu.co. 

20 cm to 100 cm per day and it depends on local soil and 

climate conditions. The full height of 15 to 30 meters 

can be reached in about 4 months. Bamboo has been 

used widely in the daily life of people for: handcraft, raw 

material for paper baskets and even as a vegetable. 

Treated bamboo is a strong material that has been used 

in some countries like China and Japan to make houses. 

More recently, Bamboo is used for concrete formwork, 

scaffolding and housing materials and even as a 

substitute for steel reinforcing rods in concrete 

construction among others. Also flooring companies are 

attempting to popularize bamboo floors made of small 

bamboo pieces which are steamed, flattened, glued 

together, finished, and cut. Taking into account, that now 

days there is a global need to have sustainable materials 

that reduce topical forest pressure, Bamboo has emerged 

as a promising alternative raw material for eco-friendly 

and sustainable construction due to its fast growth rate, 

short rotation age, and high strength. 

In America there is about 600 species of bamboo (of 

1.250 species around the world) grow from the south of 

the United States to the north of Chile and Argentina but 

only 20 of them are considered suitable for construction. 

A giant specie of bamboo called Guadua Angustifolia 

kunt has been used as a construction material in 

Colombia for more than 20 years. Even though, round

Guadua has been used in construction of structures with 

relative success, one of the problems is the variability of 

its geometry, mechanical properties and anatomical 

composition that makes this material difficult to 

characterize and prevents its use in large structures. 

Glued Laminated Guadua Bamboo (GLG) is considered 

as an excellent alternative; since some exploratory 

studies [2-4] indicated that it has mechanical properties 

as good as the best structural woods in Colombia. The 

Universidad de los Andes in Bogotá, Colombia is 

developing a comprehensive study about the 

performance of GLG as a structural material. Due to the 

lack of research on mechanical behavior of adhesives on 

GLG, the present study was focused first on determine 

the best type of adhesive as well as its optimum amount. 

After completion of this stage of research, a detail 

mechanical and physical characterization was performed. 

This paper present preliminary mechanical and physical 

characterization of GLG based on the adhesive type and 

optimum adhesive spread rate found in the first stage of 

this research. Also, a comparison of mechanical 

properties of GLG with Andean structural woods is 

established. 

2 MATERIALS AND PRODUCTION 

METHOD 

2.1 MATERIALS 

The main parts of the Guadua, the rhizomes and the 

culms are shown in Figure 1 a). The height of the culm 

varies from 20 to 30 meters and it can be separated into 

five parts each of them from 4 to 5 meters of length 

which are: cepa, basa, sobrebasa, varillón and copo. The 

structure of the culm consisted of a cylindrical wall with 

a diaphragm nodal region is shown in Figure 1 b). The 

internode at the Cepa is about 10 cm and increases at the 

Varrillón to 40 cm. Guadua culms diameter varies from 

10 to 18 cm at the Cepa and 5 to 10 cm at Varillón and 

its thickness is 0.5 cm at Varillón and 2 cm at Cepa. The 

age of the mature Guadua is difficult to estimate. So far 

there are not studies about the optimal age that give 

optimal strength. Nevertheless and based on the color of 

the culm and past experience, the age of the culms for 

construction is selected between 3 to 4 year old. 

For the currently study, three to four year old Guadua 

bamboo culms with and average base diameter of 12 cm 

to 16 cm were obtained from Caidedonia-Valle in 

Colombia located at 1400 meters in elevation. In order to 

have culms with some kind of regular cross section, only 

the three bottoms parts (cepa, basa, sobrebasa) were 

taken from the Guadua bamboo (Figure 1(a)). The length 

of each part (cepa, basa, sobrebasa) was approximately 5 

meters. The average thickness of the culm walls varied 

from 0.7 cm to 2.9 cm (Figure 1(b)). In order to ship the 

Guadua culms to the warehouse of the factory, each 

culm was cut into 2 to 3 meters long pieces. 

The following adhesives were used in the fabrication 

process of GLG: Polymer 216 FE L (Fenol-Resorcinol- 

Formaldehyde Adhesive) Polymer 103 (Melamine Urea 

Adhesive), MUF 1242 (Melamine Urea Formaldehyde 

Adhesive) and 50% Polymer 216 FE L with 50 % 

Polymer 103. 

(a) Guadua plant 

(b) Guadua culm parts 

Figure 1: General parts of guadua 

2.2 PRODUCTION METHOD 

The manufacture of the laminated Guadua was 

performed in Colguadua Ltda factory. The culms of 2m 

to 3m long were cut again into 1m to 1.5m in order to 

have straight pieces. Each piece is split in the radial 

direction into proper number of slices and the node 

sections are removed. The quasi-flattened Guadua slices 

are passed through a grinding machine to remove the 

inner and outer layers. These slices are then immersed in 

a chemical solution to protect bamboo against insects 

attack, and then dried in an oven at 80 o C to reach an 

average moisture content of 5%. Once the slices are 

dried, their four faces are polished with a machine to

flatten their surfaces obtaining Guadua laminae. Each 

Guadua lamina is about 7mm to 10 mm thick, 20mm to 

25 mm wide, and 1 m to 1.5 m long. All laminae are 

impregnated with adhesive resin along the narrow face 

(Figures 2(a) and 2(b)) and stacked to form Guadua 

sheeting. A hot press at 100 o C with a lateral pressure of 

1.2 MPa is applied to the laminae. Once the adhesive is 

cured, the Guadua sheets are glued together by the wide 

faces in order to form boards in a hot press at a pressure 

of 2 MPa for 15 minutes at 100 o C. 

(a) Glued Laminated Guadua Manufacture 

(b) Local directions 

Figure 2: Fabrication process of glued laminated guadua 

3 EXPERIMENTAL PROGRAM 

3.1 ADHESIVE CALIBRATION 

The test procedures selected for the adhesive calibration 

program were static bending and glued line shear. Five 

samples of each type (adhesive and spread rate) were 

tested on a MTS Universal Testing Machine in the 

Material Lab at the Universidad de Los Andes in Bogotá, 

Colombia. Due to the lack of glued laminated bamboo 

standards tests, the specifications given by ASTM 

D1037 (2006) and D143 (2007) were used for glued line 

shear and the static bending tests, respectively. The 

adhesive calibration program consisted of two stages. 

The objective of stage I was to determine the best 

adhesive from the point of view of its strength. For this 

stage four types of adhesive (Urea-Formaldehyde (UF), 

Melamine-Formaldehyde (MF), Melamine-Urea- 

Formaldehyde (MUF), and mixture of 50% of UF and 

50% MF) and two adhesive spread rate applied to the 

narrow (200 g/m 2 and 250 g/m 2 ) and wide (400 g/m 2 and 

450 g/m 2 ) faces of the laminae (Figure 2b) were selected. 

These spread rates were based on the adhesive 

manufacturer specifications and recommendations. Once 

the best type of adhesive is selected based on stage I 

results, stage II start to estimate the optimal spread rate. 

The spread rate used along the narrow faces was half of 

that used on the wide faces. The amount of adhesive on 

wide faces in g/m 2 was 260, 280, 300, 400 and 450. 

3.2 MECHANICAL AND PHYSICAL 

CHARACTERIZATION 

The mechanical tests performed were: compression and 

tension parallel and perpendicular to grain, and shear 

parallel to grain, and bending. Since there are no 

standards developed for glued laminated bamboo, 

ASTM D 143-94 [5] were used to perform mechanical 

tests. All the tests were conducted on a MTS Universal 

Testing Machine at the Materials Lab at the Universidad 

de Los Andes in Bogotá, Colombia. Temperature, 

moisture content, and relative humidity were recorded 

for all specimens. Besides density, radial, tangent and 

longitudinal toughness and contraction were the physical 

properties determined in this study following the ASTM 

D 2395-97 [6]. Twenty samples were used on each 

mechanical and physical test. Test procedures of the 

mechanical and physical properties are summarized as 

follows: 

3.1.1 Compression parallel to grain 

The specimens were 50 mm by 50 mm in section and 

200 mm in length as shown in Figure 3 was used. A 

continuous compressive load with a 0.6mm/min load rate 

was applied. The load-displacement curve was recorded 

and the elasticity modulus (MOE), proportional limit 

stress, and ultimate stress were determined. 

Figure 3: Compression parallel to grain specimen and 

test setup 

3.1.2 Compression perpendicular to grain 

The specimens were 50 by 50 mm in section and 150 

mm in length. A MTS load frame with a 50 mm width 

bearing metal plate was used to apply a continuous 

compressive load with a 0.3mm/min load rate. The load 

was applied until a deformation equal to 5% of the 

specimen thickness was reached, and the stress at that 

point was calculated. The proportional limit stress was 

determined.

3.1.3 Tension parallel to grain 

Figure 4 shows the test setup. The load was applied 

continuously throughout the test at a rate of 0.9 mm/min. 

The load-displacement curve was recorded and the 

elasticity modulus (MOE), proportional limit stress, and 

ultimate stress were determined. 

Figure 4: Tension parallel to grain test setup 

3.1.4 Tension perpendicular to grain 

Figure 5 shows the dimensions of the tensile test 

specimen. The load was applied continuously throughout 

the test at a 2.5 mm/min rate of the movable crosshead. 

Ultimate tensile stress was calculated. 

Figure 5: Specimen of tensile perpendicular to grain test 

3.1.5 Flexural strength 


mm in length. The test setup is shown in Figure 5. The 

load was applied at the center of a 350 mm span with a 

2.5mm/min load rate. The failure load was recorded and 

the rupture module (MOR) was calculated. 

Figure 6: Flexural Strength test setup 

3.1.6 Shear strength parallel to grain 

Dimensions of the test specimen, as well as the test setup 

are shown in Figure 6. The load was applied 

continuously throughout the test at a 0.6 mm/min rate. 

Ultimate shear stress was calculated. 

Figure 6: Specimen of shear strength parallel to grain 

test 

3.1.6 Hardness 


mm in length. The load was applied continuously 

throughout the test at a rate of motion of the movable 

crosshead of 6 mm/min. The load at which the ball 

penetrated to one half its diameter was recorded. 

3.1.7 Specific gravity and shrinkage in volume 

Test specimens were regular in shape and had 

rectangular cross sections in order to enable the 

determination of volume through linear measurement. 

Both specific gravity and shrinkage-in volume values 

were obtained from each specimen at about 12% 

moisture content of the samples in the oven-dried 

condition.

4 RESULTS AND DISCUSSION 

A total of two hundred samples were tested during the 

adhesive calibration program. A comparison of the bond 

shear strength for different types of adhesives using the 

spread rate specified by the manufacturer (stage I) is 

shown in Figure 7. Although the specimens with MUF 

adhesive exhibited slightly higher values of bond shear 

strength, there were no significant differences in this 

value among the four adhesives used. Moreover, the 

amount of the adhesive applied on the wide and narrow 

faces did not affect the value of bond shear strength. 

Similar behavior was observed for the MOE and MOR 

obtained from the bending tests with different type of 

adhesives and spread rates. Failure of the substrate 

(Guadua) was observed in all the specimens of glued line 

shear and bending tests. It seems that the spread rate 

specified by the adhesive manufacturer was on the 

conservative side producing failure the substrate. 

Since, all the adhesives behave well from the strength 

point of view and taking into account strength, durability 

and cost, the 50% UF +50% MF was the adhesive 

selected from the stage I. The optimum amount of 

adhesive spread rate at wide/narrow faces of 300/150 

g/m 2 was selected since lower adhesive spread rate of 

280/140 and 260/130 g/m2 presented a decrease in bond 

shear strength of 27%. 

Figure 7: Bond shear strength for different types of 

adhesives and spread rate. 

An average of 17.7 o C, 10.5 %, and 56.8% of 

temperature, moisture content and relative humidity 

were recorded at the moment of the tests. Table 1 

presented the 5th percentiles of the results of the 

mechanical properties of GLG and the corresponding 

values of the structural wood according to Colombian 

Seismic Regulations NSR-1998 [7]. 

The compression parallel to grain test showed a 

combination of crush with buckling failure for most of 

the specimens. The 5% percentile value of the ultimate 

stress for CPAG is about two times more than the best 

Colombian wood (type A). The failure mode of the 

compression perpendicular to grain (CPEG) test was 

crushing of the material. Relatively low value of the 5 th 

percentile was achieved in CPEG test compare to 

Colombian wood. 

Failure of the substrate (Guadua) was observed in all the 

specimens of the tension perpendicular to grain (TPG) 

test. The glue-line shear test specimens failed in the 

interlaminate adhesive as expected. Bending test resulted 

in two main failure types: tension with compression and 

horizontal shear as shown in Figure 8 a) and b), 

respectively. 

(a) Tension and compression failure 

(b) Horizontal shear failure 

Table 1: Mechanical Strength Values of Glued 

Laminated Guadua and NSR-98 Wood Grades 

Based on Table 1, all the values of the mechanical 

properties of GLG are higher than those of the best 

structural wood grade (A). In most of the cases, the 

mechanical properties of GLG are almost twice the 

values for all NSR-1998 [7] wood grades. In contrast, 

average density of GLG is about the same than that of 

structural wood grade A, since average density of GLG 

is 730 kg/m 3 whereas average density of wood grade A 

is 710 kg/m 3 . Regarding toughness and contraction in 

GLG, an average toughness of 5832 N, and radial, 

tangent and longitudinal contraction of 4.03%, 3.48% 

and 0.33% were determined. Since fibers in bamboo are 

running along the bamboo culm, less contraction is 

expected in the longitudinal direction.

5 CONCLUSIONS 

Based on the preliminary results of this research, the 

following conclusions are drawn for Glued Laminated 

Guadua Bamboo: 

Although the specimens with MUF adhesive exhibited 

slightly higher values of bond shear strength, there were 

no significant differences in this value among the four 

adhesives used on this research, with the spread rate 

specified by the adhesive manufacturer. 

Bond shear strength is a good indicator of the optimal 

amount of adhesive to be used in any glued laminated 

material. The optimal amount of adhesive is reached 

when bond shear strength is close to the strength of the 

substrate. Particularly for GLG, 300gr/m2 of adhesive 

applied on the wide faces and 150gr/m2 along the 

narrow faces is the optimum adhesive spread rate. 

Taking into account that the density of GLG is about the 

same that the best structural Colombian wood (grade A) 

and the mechanical properties of GLG are almost double 

than those of wood grade A, GLG can be a suitable 

material for construction and design of structural 

elements 

ACKNOWLEDGEMENT 

The research presented in this paper is sponsored by the 

Ministry of Agriculture and Rural Development of 

Colombia (Contract No 030-2007M3307-920-07), 

Universidad de los Andes and Colguadua Ltda. Thanks 

are to the staff of the Center of Research in Materials 

and Civil Works (CIMOC) and the Structural Lab 

Models at the Universidad de Los Andes in Bogotá, 

Colombia for their help and support. 

REFERENCES 

[1] Liese, W.: Research on bamboo. Wood Science and 

Technology, 21, pp. 189-209. 1987. 

[2] Lopez L, Correal J.: Exploratory study of the glued 

laminated bamboo Guadua angustifolia as a 

structural material. Maderas-Ciencia y Tecnología, 

11 (3): 171-182. 2009 

[3] Duran, L.: Estudio de Guadua Laminada y su 

Aplicación al Sistema Tensegrity, Thesis Work in 

Architecture, Universidad Nacional de Colombia 

sede Bogotá, 2003. 

[4] Vanegas, G.: Guadua Laminada Investigación, 

Experimentación y Aplicación, Thesis Work in 

Architecture, Universidad Nacional de Colombia 

sede Bogotá, 2003. 

[5] ASTM-D143-94, Standard Methods of Testing 

Small Clear Specimens of Timber, Sección 4, Vol 

4.1wood, July 1997. 

[6] ASTM-D2395-97, Standard Test Methods for 

Specific Gravity of Wood and Wood-Based 

Material, Sección 4, Vol 4.1wood, July 1997. 

[7] Asociación Colombiana de Ingeniería Sísmica, 

Normas Colombianas de diseño sismorresistente 

(NSR-98), Asociación colombiana de Ingeniería 

Sísmica, Bogotá, Colombia, 1997.

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