# Interlaminar Shear Properties of Bamboo Composite for Structural Applications

^{1}

^{2}

^{3}

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*Fibers*)

## Abstract

**:**

## 1. Introduction

^{3}, structural efficiency (see [19]) of bamboo composite is more than steel, concrete, and most common structural timbers. This suggests that bamboo composite could be used as load bearing member in construction. In particular, the high tensile and compressive capacity of bamboo composite could be effectively employed in truss structures.

## 2. Experimental Program

#### 2.1. Material

#### 2.2. Testing BC Shear Strength in Lab Condition

## 3. Results and Discussion

#### 3.1. Developing a Probabilistic Formulation for Shear Strength of BC

- $y$: Distance from centroid
- ${\tau}_{e}\left(y\right)$: Effective shear stress at $y$
- $k$: Stress concentration factor
- $\tau \left(y\right)$: Shear stress where crack happens
- ${\tau}_{u}$: Ultimate shear strength when no significant flaw exists

- ${L}_{u}=\frac{4}{3}\left(b\times w\right){\tau}_{u}$
- $\nu $: Expected number of flaws in the unit of volume
- $\mathsf{\Delta}\mathrm{v}=40\text{}\mathrm{mm}\text{}\left(\mathrm{length}\text{}\mathrm{of}\text{}\mathrm{samples}\right)\times \mathrm{b}\text{}\times \mathrm{dy}$
- $b$: Width of sample
- $h$: Height (depth) of sample

- $E\left(failureload\right)$: Expected failure load for a sample.
- ${\tau}_{app}$: Apparent shear strength in a sample

^{−6}for the first group, as shown in Figure 5. Then, using $\nu =88\times {10}^{-6}$, the expected value of ${\tau}_{app}$ was obtained from Equation (6) and compared with the mean value of ${\tau}_{app}$ obtained from experimental data points in the second group. The difference between the expected value of ${\tau}_{app}$ from Equation (6) and the value of ${\tau}_{app}$ from data points in the second group was 5.4%. This suggests that $\nu =88\times {10}^{-6}$ could be a good estimation for the rate of flaws in BC. Given $\nu =88\times {10}^{-6}$, there was an effective flaw in every 11.36 cm

^{3}in the average volume of BC.

#### 3.2. Effect of Moisture on Interlaminar Shear Properties of BC

## 4. Conclusions and Structural Design Considerations Associated with Shear Properties of BC

^{2}of 0.80 fits the experimental data points.

^{3}of BC volume based on this model. The probabilistic model developed herein could be used in structural design and evaluating safety factors for BC members under shear stress. Safety factors set for BC should include member size, since the strength of BC is shown to be size-dependent.

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 2.**Sample force–deflection (3-point test); specimens in equilibrium conditions of T = 20 °C and H = 60%.

**Figure 4.**(

**A**) Absolute distance of first cracks in specimens relative to section centroid. (

**B**) Stress concentration as in Equation (1).

**Figure 7.**Change of shear strength by environmental humidity. Shear tests were conducted on samples after 21 days of exposure, and the mean results are shown.

**Figure 8.**Force–deflection (3-point test); samples were exposed to conditions of T = 20 °C and H = 40% for three days.

**Figure 9.**Force–deflection (3-point test); samples were exposed to the conditions of T = 20 °C and H = 40% for seven days.

**Figure 10.**Three-point shear test force–deflection diagrams under different environmental humidity conditions—exposure time = 21 Days.

**Figure 11.**Force–deflection (3-point test); local failure does not happen in a few S-40-3 samples. Samples were exposed to T = 20 °C for three and seven days. Original conditions: T = 20 °C and H = 60%. Only in a few samples did cracks occur in the middle.

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**MDPI and ACS Style**

Rajabipour, A.; Javadian, A.; Bazli, M.; Masia, M.
Interlaminar Shear Properties of Bamboo Composite for Structural Applications. *Fibers* **2022**, *10*, 59.
https://doi.org/10.3390/fib10070059

**AMA Style**

Rajabipour A, Javadian A, Bazli M, Masia M.
Interlaminar Shear Properties of Bamboo Composite for Structural Applications. *Fibers*. 2022; 10(7):59.
https://doi.org/10.3390/fib10070059

**Chicago/Turabian Style**

Rajabipour, Ali, Alireza Javadian, Milad Bazli, and Mark Masia.
2022. "Interlaminar Shear Properties of Bamboo Composite for Structural Applications" *Fibers* 10, no. 7: 59.
https://doi.org/10.3390/fib10070059