# The Influence of Panel Lay-Up on the Characteristic Bending and Rolling Shear Strength of CLT

^{1}

^{2}

^{*}

## Abstract

**:**

## 1. Introduction

^{2}for the rolling shear strength of European spruce, independent of the strength class. The shear tests performed by Sikora et al. [9] on three-layer and five-layer panels, have shown that rolling shear values decrease with the panel thickness, with the mean reported values ranging between 1.0 N/mm

^{2}to 2.0 N/mm

^{2}. The geometric properties of the individual boards have also been shown to influence the rolling shear behaviour [3,16,17]. As a result, for the rolling shear stresses in the layers of the CLT loaded out-of-plane, a minimum board width-to-thickness ratio of four is proposed; otherwise, a reduced rolling shear resistance has to be considered [1]. Brandner et al. [3] state that, in accordance with practical applications, the characteristic rolling strength values, ƒ

_{r},

_{CLT,k}, of 1.40 N/mm

^{2}and 0.80 N/mm

^{2}should be assumed for width-to-thickness ratios greater than or equal to four and width-to-thickness ratios less than four, respectively. According to EN 16351 [1], if the boards are edge glued, a characteristic rolling shear strength of 1.10 N/mm

^{2}may be applied. If edge glueing is not used, and a minimum board width-to-thickness ratio is not achieved, a characteristic rolling shear value of 0.70 N/mm

^{2}is recommended. The typical mean values of rolling shear strength from the experimental results range from 1.0 N/mm

^{2}to 2.0 N/mm

^{2}, and while there are characteristic design values proposed dependent on the ratio of the board width-to-thickness, there is no information on the influence of the number of layers and the position of the transverse layer relative to the neutral axis of the CLT panel.

## 2. Materials and Specimen Manufacture

^{2}was observed. All of the panels were manufactured using a one-component PUR adhesive (PURBOND HB S309), with a spreading rate of 160 g/m

^{2}, and a pressure (face bonding only, no edge bonding) of 0.6 N/mm

^{2}. These manufacturing parameters are based on the adhesive qualification testing undertaken by Sikora et al. [4]. The pressure was applied using steel plates, tightened with M20 steel bolts to provide the required compressive force, and maintained for a period of 120 min. The manufactured panels were then stored in a conditioning chamber for a period of one month, prior to experimental testing.

## 3. Experimental Programme

#### 3.1. Introduction

#### 3.2. Bending Test and Rolling Shear Test

_{L}and E

_{G}, respectively), and the local and global stiffnesses (E

_{L}I and E

_{G}I, respectively) of each panel to be calculated.

_{max}) and rolling shear stress (τr

_{max}) in the specimens loaded perpendicular to the plane were calculated using the maximum test values of the bending moment and the shear force, respectively. The following theoretical methods were applied to evaluate the stresses in the timber: layered beam theory, Gamma beam theory, and shear analogy theory. A comparison of these approximate verification procedures for CLT has been comprehensively investigated by Bogensperger et al. [24] and Li [25]. For the stress calculations in this study, the mean value used for the modulus of elasticity parallel to the grain was 8098 N/mm

^{2}, in line with the test results on the modulus of the elasticity of the Sitka spruce boards. The normal and shear stress distributions in a five-layer panel are illustrated in Figure 2a,b, respectively. As the modulus of elasticity perpendicular to the grain (E

_{90}) is very low for timber, the contribution of the transverse layers to the bending performance was excluded from the calculations. For the Gamma beam theory calculations, a constant value of 50 N/mm

^{2}was used for the rolling shear modulus, G

_{R}, in accordance with Bogensperger et al. [20]. In Figure 2b, the distinction between the maximum shear (τ

_{max}) and maximum rolling shear (τr

_{max}) strengths can be seen.

_{0}). The maximum rolling shear stress is the greatest in the transverse layers (E

_{90}) either side of the middle layer (E

_{0}). In a three-layer panel, the maximum shear stress and maximum rolling shear stress both occur in the central transverse layer of the CLT panel.

_{CLT}) based on composite theory is used for comparison with the experimental results. This is calculated using Equation (1).

- E
_{0}= mean MOE of the batch of timber boards used to manufacture the CLT panels. - I
_{i}= second moment of area of the board, i. - A
_{i}= area of the board, i. - y
_{i}= distant from the neutral axis of the panel to the centroid of the board, i. - n = total number of boards, orientated parallel to the span.

_{s}, to account for the sample size.

## 4. Experimental Results

#### 4.1. Introduction

#### 4.2. Bending Test Results

_{G}and E

_{L}, respectively) and bending stiffness (E

_{G}I and E

_{L}I, respectively) results of each panel of the three-layer B-3-20, five-layer B-5-20, and three-layer B-3-40 configurations, respectively. The maximum theoretical bending strengths calculated using the layered beam theory, gamma method, and shear analogy method are also presented in addition to the failure mode. The average, standard deviation, and fifth percentile values are also tabulated.

^{2}, 35.71 N/mm

^{2}, and 35.93 N/mm

^{2}, respectively. These values are similar to one another with the almost identical results from the layered beam theory and the shear analogy method, and a slightly reduced value for the gamma method. The comparative values for the 100 mm B-5-20 configuration are slightly reduced with bending strength values of 34.43 N/mm

^{2}, 34.35 N/mm

^{2}, and 34.08 N/mm

^{2}, respectively, and the 120 mm B-3-40 panel configuration values are further reduced with bending strength values of 29.47 N/mm

^{2}, 29.25 N/mm

^{2}, and 29.43 N/mm

^{2}, respectively, from the layered beam theory, gamma method, and shear analogy method.

^{2}, 23.98 N/mm

^{2}, and 24.08 N/mm

^{2}, respectively. The characteristic bending strength for the 100 mm B-5-20 panel configuration were found to be greater than that of the 60 mm B-3-20 panel configuration, with comparative characteristic values of 26.38 N/mm

^{2}, 26.34 N/mm

^{2}, and 26.13 N/mm

^{2}for the layered beam theory, gamma method, and shear analogy method, respectively. While the mean maximum bending strength results are lower than that observed in the panel configuration B-3-20, the characteristic strength values are higher. This indicates less scatter in the experimental results and more predictable failure behaviour from the five-layer configuration. The characteristic bending strength for the 120 mm B-3-40 panel configuration from the layered beam theory, gamma method, and shear analogy method were 19.52 N/mm

^{2}, 19.38 N/mm

^{2}, and 19.49 N/mm

^{2}, respectively. This is a low result when compared to the three-layer configuration B-3-20 with a reduced board thickness of 20 mm, but the values are still relatively high considering the raw material used to manufacture the panels was C16 grade.

^{12}Nmm

^{2}and 1.27 × 10

^{12}Nmm

^{2}using global and local deformations, respectively, was recorded for the thickest three-layer panels of the 40 mm layers (B-3-40) as expected. The corresponding values for the five-layer panels (B-5-20) were 5.19 × 10

^{11}Nmm

^{2}and 6.63 × 10

^{11}Nmm

^{2}, and for the thinner three-layer panels (B-3-20), the values were 1.28 × 10

^{11}Nmm

^{2}and 1.67 × 10

^{11}Nmm

^{2}. As seen in Figure 5, the global stiffness results are in good agreement with the theoretical stiffness results. The same cannot be said for the local stiffness results, but it should be noted that the values calculated using the local deformation measurements presented greater scatter than those from the global deformations. This is thought to be a consequence of local variabilities within test specimens that influences the local deformations to a greater extent than measured globally. This phenomenon is in agreement with the finding made by Ridley-Ellis et al. [27], who suggested that the primary reason the for observed differences between the global and local deformations in timber is not necessarily attributed to the shear deformations, but to the variation of modulus of elasticity within a specimen.

^{2}, assumed for the rolling shear modulus, G

_{R}[9]. When comparing the different panel configurations, the highest mean values of approximately 36 N/mm

^{2}were obtained for the thinnest samples (B-3-20), and the lowest of approximately 29 N/mm

^{2}for the thickest (B-3-40). Based on these results, there is a general tendency that the thicker the CLT panel, the lower the bending strength.

#### 4.3. Rolling Shear Test Results

_{max}) and the maximum rolling shear strength (τr

_{max}) in the five-layer panels (Figure 2b). This is due to the maximum shear stress occurring in a board at the neutral axis, which is orientated in the longitudinal direction (E

_{0}). The maximum rolling shear stress occurs in the adjacent transverse layers (E

_{90}) and is accounted for and presented by analysing the entire cross section.

^{2}, 2.14 N/mm

^{2}, and 2.22 N/mm

^{2}, respectively. The reduced mean rolling shear strength values were observed for the 100 mm S-5-20 panel configuration, where the mean rolling shear strength from the layered beam theory, gamma method, and shear analogy method were 1.40 N/mm

^{2}, 1.39 N/mm

^{2}, and 1.39 N/mm

^{2}, respectively. By comparison, the mean rolling shear strength for the thickest 120 mm S-3-40 panel configuration was further reduced with the rolling shear values from the layered beam theory, gamma method, and shear analogy method of 1.33 N/mm

^{2}, 1.30 N/mm

^{2}, and 1.35 N/mm

^{2}, respectively. The results indicated similar trends observed for the bending strength specimens, the thicker the CLT panel, the lower its rolling shear strength.

^{2}, 1.63 N/mm

^{2}, and 1.69 N/mm

^{2}, respectively from the layered beam theory, the gamma method, and the shear analogy method, calculated in accordance to EN 14358 [26]. The characteristic rolling shear strength values for the 100 mm S-5-20 panel configuration from the layered beam theory, gamma method, and shear analogy method were 1.07 N/mm

^{2}, 1.06 N/mm

^{2}, and 1.06 N/mm

^{2}, respectively, and the characteristic rolling shear strength for the 120 mm S-3-40 panel configuration from the layered beam theory, gamma method, and shear analogy method are 0.90 N/mm

^{2}, 0.88 N/mm

^{2}, and 0.91 N/mm

^{2}, respectively.

^{2}to 2.1 N/mm

^{2}, and a characteristic value of 1.0 N/mm

^{2}for the rolling shear strength of European spruce was proposed. The mean characteristic rolling shear values of the tests were found to range from 0.88 N/mm

^{2}to 1.69 N/mm

^{2}. The lowest values were observed in the thickest panel configuration, S-3-40. The boards used in this panel configuration had board width-to-thickness ratios less than four. The two most common design recommended values for such layers are 0.7 N/mm

^{2}, prescribed by EN 16351 [1], and 0.8 N/mm

^{2}, prescribed by Brandner et al. [3]. In Figure 10, the influence of the panel thickness and number of layers on the rolling shear strength distribution can be seen. When examining the rolling shear strength distribution, there is a decrease in the mean and characteristic shear strength with the increasing panel thickness. The variability in the distribution of the rolling shear strength for the five-layer configuration is seen to be less than either of the three-layer configurations.

## 5. Conclusions

- -
- The findings of this research project suggest that C16 timber is suitable for the manufacture of CLT products.
- -
- The global bending stiffness results are in good agreement with the theoretical bending stiffness results, regardless of the panel thickness or lay-up studied.
- -
- The mean and characteristic bending strength was higher than expected for the CLT panels manufactured from C16 grade timber.
- -
- The test results generally indicated a decreasing bending strength with an increasing panel thickness. The highest mean bending strength value, of approximately 36 N/mm
^{2}, was obtained for the thinnest panels (B-3-20), and the lowest, of approximately 29 N/mm^{2}, for the thickest (B-3-40). - -
- The characteristic bending strength was found to be influenced by the number of layers, with the highest characteristic bending strength values being achieved by the intermediate 100 mm five-layer panel configuration. The homogenising or laminating effect resulting from the increased number of layers in a CLT panel may be utilised to achieve an additional capacity in the structural design of the CLT structures.
- -
- The mean rolling shear strength was found to reduce with the increasing panel thickness. The mean values ranged between 1.30 N/mm
^{2}and 2.22 N/mm^{2}, which is in line with the rolling shear values presented by Blaß and Görlacher [23] of between 1.2 N/mm^{2}and 2.1 N/mm^{2}, for European spruce. - -
- The characteristic rolling shear strength of the panels was found to range from 0.88 N/mm
^{2}to 1.69 N/mm^{2}. Given that the board width-to-thickness ratio in this study was less than four, the experimental results are greater than the characteristic rolling shear values of 0.7 N/mm^{2}, prescribed by EN 16351 [1], and 0.8 N/mm^{2}, prescribed by Brandner et al. [3]. - -
- The results show that the mean bending and rolling shear strength decrease with the increasing panel thickness, irrespective of the number of layers. The characteristic bending strength is also influenced by the panel thickness, but the number of layers is found to have a significant impact.
- -
- To further examine these initial findings, tests are required on the panels of equal thickness comprising a different number of layers to allow the influence of the layer thickness on the bending and rolling shear strength to be assessed.

## Author Contributions

## Funding

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 1.**Four-point bending test set-up on a five-layer cross laminated timber (CLT) panel (B-5-20-7) over a span of 2400 mm.

**Figure 2.**CLT element loaded out of plane. (

**a**) Normal stress distribution through a five-layer panel assuming E

_{90}= 0 N/mm

^{2}; (

**b**) shear stress distribution assuming E

_{90}= 0 N/mm

^{2}.

**Figure 5.**Mean bending stiffness results per meter width and the influence of panel configuration and depth.

**Figure 8.**Rolling shear failure: (

**a**) five-layer panel (S-5-20-5) and (

**b**) three-layer panel (S-3-40-7).

**Figure 10.**Rolling shear strength distribution and influence of panel thickness and number of layers.

Specimen Label | Number of Layers | Thickness of Layer (mm) | Panel Thickness (mm) | Panel Width (mm) | Span in Bending (mm) | Test Properties |
---|---|---|---|---|---|---|

B-3-20 | 3 | 20 | 60 | 584 | 1440 | Bending strength and stiffness |

B-5-20 | 5 | 20 | 100 | 584 | 2400 | Bending strength and stiffness |

B-3-40 | 3 | 40 | 120 | 584 | 2880 | Bending strength and stiffness |

S-3-20 | 3 | 20 | 60 | 584 | 720 | Shear (rolling) strength |

S-5-20 | 5 | 20 | 100 | 584 | 1200 | Shear (rolling) strength |

S-3-40 | 3 | 40 | 120 | 584 | 1440 | Shear (rolling) strength |

**Table 2.**Bending test results for three-layer B-3-20 configuration. E

_{G}—global elastic moduli; E

_{G}I—global elastic moduli; E

_{L}—local stiffness; E

_{L}I—global stiffness.

Panel I.D | E_{G} (N/mm^{2}) | E_{G}I(Nmm ^{2}) | E_{L} (N/mm^{2}) | E_{L}I(Nmm ^{2}) | Max. Bending Strength, (N/mm^{2}) | Failure Mode | ||
---|---|---|---|---|---|---|---|---|

Layered Beam Theory | Gamma Method | Shear Analogy Method | ||||||

B-3-20-1 | 8840.9 | 8.26 × 10^{10} | 11,510.4 | 1.07 × 10^{11} | 40.44 | 40.08 | 40.39 | Tension |

B-3-20-2 | 7967.8 | 7.44 × 10^{10} | 11,785.4 | 1.10 × 10^{11} | 37.98 | 37.69 | 37.93 | Tension |

B-3-20-3 | 7342.6 | 7.48 × 10^{10} | 7771.9 | 7.92 × 10^{10} | 36.10 | 35.83 | 36.05 | Tension |

B-3-20-4 | 8326.2 | 8.29 × 10^{10} | 10,671.6 | 1.06 × 10^{11} | 44.34 | 43.98 | 44.29 | Tension |

B-3-20-5 | 6209.4 | 6.31 × 10^{10} | 9088.8 | 9.24 × 10^{10} | 24.60 | 24.45 | 24.57 | Tension |

B-3-20-6 | 6340.8 | 6.28 × 10^{10} | 6569.7 | 6.50 × 10^{10} | 32.03 | 31.83 | 31.99 | Tension |

B-3-20-7 | 6430.6 | 6.73 × 10^{10} | 10,164.6 | 1.06 × 10^{11} | 36.14 | 35.90 | 36.09 | Tension |

B-3-20-8 | 7100.9 | 7.57 × 10^{10} | 8854.8 | 9.82 × 10^{10} | 36.19 | 35.93 | 36.14 | Tension |

Average | 7319.9 | 7.29 × 10^{10} | 9552.1 | 9.56 × 10^{10} | 35.98 | 35.71 | 35.93 | - |

Std. Dev. | 983.9 | 7.91 × 10^{9} | 1821.1 | 1.60 × 10^{10} | 5.84 | 5.77 | 5.83 | - |

5th perc. | 5417.2 | 5.70 × 10^{10} | 6030.9 | 6.27 × 10^{10} | 24.11 | 23.98 | 24.08 | - |

Panel I.D | E_{G} (N/mm^{2}) | E_{G}I(Nmm ^{2}) | E_{L} (N/mm^{2}) | E_{L}I (Nmm^{2}) | Max. Bending Strength, (N/mm^{2}) | Failure Mode | ||
---|---|---|---|---|---|---|---|---|

Layered Beam Theory | Gamma Method | Shear Analogy Method | ||||||

B-5-20-1 | 6409.1 | 3.08 × 10^{11} | 10,511.9 | 5.05 × 10^{11} | 34.50 | 34.37 | 34.20 | Tension |

B-5-20-2 | 6389.0 | 3.07 × 10^{11} | 7322.5 | 3.51 × 10^{11} | 32.26 | 32.20 | 31.98 | Tension |

B-5-20-3 | 6823.0 | 3.28 × 10^{11} | 8130.5 | 3.90 × 10^{11} | 34.96 | 34.89 | 34.27 | Tension |

B-5-20-4 | 5806.1 | 2.69 × 10^{11} | 6688.3 | 3.10 × 10^{11} | 27.68 | 27.64 | 27.44 | Tension |

B-5-20-5 | 5730.3 | 2.82 × 10^{11} | 7433.6 | 3.66 × 10^{11} | 36.45 | 36.39 | 36.13 | Tension |

B-5-20-6 | 5588.9 | 2.65 × 10^{11} | 8223.8 | 3.91 × 10^{11} | 31.57 | 31.52 | 31.30 | Tension |

B-5-20-7 | 6623.2 | 3.16 × 10^{11} | 7874.2 | 3.76 × 10^{11} | 37.05 | 36.98 | 36.72 | Tension |

B-5-20-8 | 7112.3 | 3.11 × 10^{11} | 8140.7 | 3.56 × 10^{11} | 40.93 | 40.85 | 40.57 | Tension |

Average | 6310.2 | 2.98 × 10^{11} | 8040.7 | 3.81 × 10^{11} | 34.43 | 34.35 | 34.08 | - |

Std. Dev. | 551.7 | 2.29 × 10^{10} | 1127.5 | 5.63 × 10^{10} | 4.00 | 3.99 | 3.96 | - |

5th perc. | 5183.7 | 2.51 × 10^{11} | 5971.1 | 2.78 × 10^{11} | 26.38 | 26.34 | 26.13 | - |

Panel I.D | E_{G} (N/mm^{2}) | E_{G}I (Nmm^{2}) | E_{L} (N/mm^{2}) | E_{L}I (Nmm^{2}) | Max. Bending Strength, (N/mm^{2}) | Failure Mode | ||
---|---|---|---|---|---|---|---|---|

Layered Beam Theory | Gamma Method | Shear Analogy Method | ||||||

B-3-40-1 | 7406.6 | 6.23 × 10^{11} | 8974.4 | 7.55 × 10^{11} | 22.39 | 22.22 | 22.36 | Tension |

B-3-40-2 | 7845.8 | 6.60 × 10^{11} | 9310.4 | 7.83 × 10^{11} | 26.17 | 25.96 | 26.14 | Tension |

B-3-40-3 | 7437.8 | 6.25 × 10^{11} | 10,780.4 | 9.07 × 10^{11} | 26.87 | 26.67 | 26.84 | Tension |

B-3-40-4 | 7252.2 | 5.56 × 10^{11} | 8212.9 | 6.29 × 10^{11} | 33.85 | 33.62 | 33.81 | Tension |

B-3-40-5 | 7254.4 | 5.86 × 10^{11} | 7568.2 | 6.11 × 10^{11} | 32.85 | 32.62 | 32.81 | Tension |

B-3-40-6 | 6005.5 | 4.90 × 10^{11} | 6925.0 | 5.65 × 10^{11} | 24.05 | 23.91 | 24.02 | Tension |

B-3-40-7 | 6641.7 | 5.50 × 10^{11} | 9065.1 | 7.51 × 10^{11} | 32.80 | 32.58 | 32.76 | Tension |

B-3-40-8 | 8420.2 | 6.94 × 10^{11} | 11,014.1 | 9.07 × 10^{11} | 36.75 | 36.44 | 36.70 | Tension |

Average | 7283.0 | 5.98 × 10^{11} | 8981.3 | 7.38 × 10^{11} | 29.47 | 29.25 | 29.43 | - |

Std. Dev. | 726.5 | 6.57 × 10^{10} | 1429.3 | 1.29 × 10^{11} | 5.23 | 5.19 | 5.23 | - |

5th perc. | 5792.6 | 4.65 × 10^{11} | 6239.6 | 4.93 × 10^{11} | 19.52 | 19.38 | 19.49 | - |

Panel I.D | Rolling Shear Strength (N/mm^{2}) | Failure Mode | ||
---|---|---|---|---|

Layered Beam Theory | Gamma Method | Shear Analogy Method | ||

S-3-20-1 | 1.90 | 1.85 | 1.92 | Shear |

S-3-20-2 | 2.03 | 1.98 | 2.05 | Shear |

S-3-20-3 | 2.30 | 2.24 | 2.33 | Shear |

S-3-20-4 | 2.42 | 2.37 | 2.46 | Shear |

S-3-20-5 | 2.03 | 1.99 | 2.06 | Shear |

S-3-20-6 | 2.43 | 2.37 | 2.46 | Shear |

S-3-20-7 | 1.88 | 1.84 | 1.91 | Shear |

S-3-20-8 | 2.55 | 2.49 | 2.58 | Shear |

Average | 2.19 | 2.14 | 2.22 | - |

Std. Dev. | 0.26 | 0.26 | 0.27 | - |

5th perc. | 1.67 | 1.63 | 1.69 | - |

Panel I.D | Rolling Shear Strength (N/mm^{2}) | Failure Mode | ||
---|---|---|---|---|

Layered Beam Theory | Gamma Method | Shear Analogy Method | ||

S-5-20-1 | 0.65 | 0.65 | 0.65 | Delamination |

S-5-20-2 | 1.33 | 1.33 | 1.32 | Shear |

S-5-20-3 | 1.11 | 1.10 | 1.10 | Shear |

S-5-20-4 | 1.32 | 1.31 | 1.31 | Shear |

S-5-20-5 | 1.43 | 1.43 | 1.42 | Shear |

S-5-20-6 | 1.50 | 1.49 | 1.49 | Shear |

S-5-20-7 | 1.56 | 1.56 | 1.55 | Shear |

S-5-20-8 | 1.53 | 1.52 | 1.52 | Shear |

Average | 1.40 | 1.39 | 1.39 | - |

Std. Dev. | 0.16 | 0.16 | 0.16 | - |

5th perc. | 1.07 | 1.06 | 1.06 | - |

Panel I.D | Rolling Shear Strength (N/mm^{2}) | Failure Mode | ||
---|---|---|---|---|

Layered Beam Theory | Gamma Method | Shear Analogy Method | ||

S-3-40-1 | 0.98 | 0.96 | 0.99 | Shear |

S-3-40-2 | 1.16 | 1.14 | 1.18 | Shear |

S-3-40-3 | 1.17 | 1.15 | 1.18 | Shear |

S-3-40-4 | 1.28 | 1.26 | 1.30 | Shear |

S-3-40-5 | 1.57 | 1.53 | 1.59 | Shear |

S-3-40-6 | 1.55 | 1.52 | 1.57 | Shear |

S-3-40-7 | 1.39 | 1.36 | 1.41 | Shear |

S-3-40-8 | 1.55 | 1.52 | 1.57 | Shear |

Average | 1.33 | 1.30 | 1.35 | - |

Std. Dev. | 0.22 | 0.22 | 0.22 | - |

5th perc. | 0.90 | 0.88 | 0.91 | - |

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

## Share and Cite

**MDPI and ACS Style**

O’Ceallaigh, C.; Sikora, K.; Harte, A.M.
The Influence of Panel Lay-Up on the Characteristic Bending and Rolling Shear Strength of CLT. *Buildings* **2018**, *8*, 114.
https://doi.org/10.3390/buildings8090114

**AMA Style**

O’Ceallaigh C, Sikora K, Harte AM.
The Influence of Panel Lay-Up on the Characteristic Bending and Rolling Shear Strength of CLT. *Buildings*. 2018; 8(9):114.
https://doi.org/10.3390/buildings8090114

**Chicago/Turabian Style**

O’Ceallaigh, Conan, Karol Sikora, and Annette M. Harte.
2018. "The Influence of Panel Lay-Up on the Characteristic Bending and Rolling Shear Strength of CLT" *Buildings* 8, no. 9: 114.
https://doi.org/10.3390/buildings8090114