Question $5(15$ points$)$

Answer the following questions conceptually by providing sufficient explanations.

$($a$)$ What is the purpose of using high quality tension laminations for glulam members?

$($b$)$ If the ratio of the Euler buckling stress to the pure axial strength $($without considering unstability$)$ in a timber column is $0\mathrm{.}4,$ which of the failure modes do you expect this column to experience, buckling or compression failure? Why?

$($c$)$ What is the reason that the combined axial tensile stress calculated from superposition due to axial force and bending $(\backslash (\backslash$mathrm$\{$P$\}/\backslash$mathrm$\{$A$\}+\backslash$mathrm$\{$M$\}/\backslash$mathrm$\{$S$\}\backslash ))$ is not used directly for designing of a wood member subjected to combined bending and tension and an interaction diagram is used instead?

$($d$)$ What is the reason for using the force modification factor $\backslash ((\backslash$mathrm$\{$R$\})\backslash )$ to calculate earthquake loading? What are the consequences of using this reduced force?

$($e$)$ Around $1990,$ someone at the University of Michigan asked every academic department to offer one question that they thought every student in that department should be able to answer to be able to graduate. Adopting this anecdote to Engr $427,$ state one such important conceptual question in wood design that everyone should be able to answer. Note that you don't need to provide the answer to this question, stating only the question is sufficient.