The wooden members A and B are to be joined by plywood splice plates that will be fully glued on the surfaces in contact. As part of the design of the joint, and knowing that the clearance between the ends of the members is to be 8 mm, determine the smallest allowable length L if the average shearing stress in the glue is not to exceed 800 kPa.
Fig. P8.13

Let us draw the wooden members with splice plates:
There are four parts of glue sharing the \(24 \mathrm{kN}\) as 2 separate parts.
Given average shearing stress in the glue is limited to \(\tau_{\text {ghee }}=800 \mathrm{kPa}\)
Half of the \(24 \mathrm{kN}\) force should be shared by each area part for shearing.
Calculate the cross-sectional area. Let \(A\) be the one of the four areas.
$$ \begin{array}{l} \tau_{\text {ghe }}=\frac{F}{A} \\ 800 \mathrm{kPa}=\frac{12 \mathrm{kN}}{A} \\ A=\frac{12}{800} \\ =0.015 \mathrm{~m}^{2} \mid \frac{10^{6} \mathrm{~mm}^{2}}{1 \mathrm{~m}^{2}} \\ =15000 \mathrm{~mm}^{2} \end{array} $$
Calculate the length of the one glued area. Consider from figure.
$$ \begin{aligned} A &=l \times b \\ l &=\frac{A}{b} \\ &=\frac{15000}{100} \\ &=150 \mathrm{~mm} \end{aligned} $$
Calculate the total length of the glued area. Consider from the figure.
$$ \begin{aligned} L &=2 \times l+8 \\ L &=2 \times 150+8 \\ &=300+8 \\ &=308 \mathrm{~mm} \end{aligned} $$
Therefore, the allowable length of glue is \(308 \mathrm{~mm}\).