# Flexural Performance of Novel Nail-Cross-Laminated Timber Composite Panels
## 2 Experimental Program  
### Test Specimens  
Six groups of specimens were investigated in this flexural test. All specimens were made of Canadian SPF (including spruce, pine, and fir), namely spruce-pine-hemlock mixed standard material. All specimens were connected by nails. The details of the test specimens are outlined in Table 1. The material properties of the wood used in this test are summarized in Table 2. Vertically and horizontally textured solid wood panels were interlaced orthogonally to each other, thus forming the new NCLT panels. Vertically textured solid wood panels were 2350 mm in length and 235 mm in width with 38 mm thickness. The horizontally textured solid wood panels were 705 mm in length, 235 mm in width, and 38 mm in thickness. The 3-layer and 5-layer NCLT panels were nailed from bottom to top, that is, the nail was nailed from the bottom layer to the first layer. When the nailing angle was 0\({}^{\circ}\), the nail gun was positioned perpendicular to the surface of the nail panels. When the nail was shot at 30\({}^{\circ}\), an auxiliary nailing bracket was used. Figures 1a-d and 2a-e show partial detail views of the longitudinal section of each set of test specimens and a partial detail of the top view. In the 5-layer CLT panel structure, the arrangement of nails between the first and second layers was the same as the one between the third and fourth layers, as shown in Figure 2d. The nail arrangement between the second and third layers was the same as that between the fourth and fifth layers, as shown in Figure 2e.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Test** & **Specimen** & **Number** & **Nail** & **Types** & **Nail** & **Total Number** & **Size\textbackslash{}mm** \\
**Sequence** & **Number** & **of Layers** & **Incidence Angle** & **of Nails** & **Specifications\textbackslash{}mm** & **of Nails** & **Size\textbackslash{}mm** \\ \hline
1 & KWL30070235480 & 3 & 0\({}^{\circ}\) & Threaded nail & 2.5, 70 & 480 & \(2350\times 705\times 114\) \\
2 & KWG30070235240 & 3 & 0\({}^{\circ}\) & Polished rod & 3.5, 70 & 240 & \(2350\times 705\times 114\) \\
3 & KWG33080235240 & 3 & 30\({}^{\circ}\) & Polished rod & 3.5, 80 & 240 & \(2350\times 705\times 114\) \\
4 & KWS30070235240 & 3 & 0\({}^{\circ}\) & Screw & 3.0, 70 & 240 & \(2350\times 705\times 114\) \\
5 & KWL30070235240 & 3 & 0\({}^{\circ}\) & Threaded nail & 2.5, 70 & 240 & \(2350\times 705\times 114\) \\
6 & KWL50070235480 & 5 & 0\({}^{\circ}\) & Threaded nail & 2.5, 70 & 480 & \(2350\times 705\times 114\) \\ \hline \multicolumn{7}{c}{KW indicates the bending resistance; L indicates the nail type; G indicates polished rod type; S indicates screw type; the first digit is the number of layers; the second and third digits represent the nail incidence angle; fourth and five digits represent the length of the nail; the last three digits represent the total number of nails.} \\ \end{tabular}
\end{table}
Table 1: Details of test specimen.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Species** & **Bending** & **Traormal** & **Vertical** & & & \\
**Strength/MPa** & **Texture** & **Texture** & **Tensile** & **Elastic** & **Density** & **Water Content** \\
**Strength/MPa** & **Compressive** & **Compressive** & **Strength/MPa** & & & **(\%)** \\ \hline Spruce & 12.5 & 37.8 & 4.1 & 92.39 & 11.2 & 430 & 15 \\ Pine & 10.9 & 43.2 & 3.6 & 83.66 & 10.9 & 455 & 15 \\ Fir & 12.1 & 38.9 & 3.8 & 88.26 & 11.4 & 440 & 15 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Physical properties of spruce, pine, and fir (SPF).  
Figure 1: Partial detail view of specimens.