An upside$-$down steel A frame shown in the figure will

be bolted to steel beams on the ceiling of a machine

room using $3//8$ in$-10$ UNC grade $8$ bolts. This frame is to

support the $10,000$lbf vertical load as illustrated. The

total bolt grip is $2$ inches, which includes the thickness of

the steel beam, the A$-$frame feet, and the steel washers

used. The bolts are $3$ in $.$ long and have a threaded length

of $1\mathrm{.}75$ in $.$ The nuts have a width of $1\mathrm{.}125$ in $.$ and a height

of $0\mathrm{.}640$ in$.$

a$.$ Determine the bolt stiffness K$\_($b$).$

b$.$ Determine the members stiffness K$\_($m$).$

c$.$ Determine the Stiffness Constant C$.$

d$.$ Determine the tightening torque T that should be used if the connection is permanent

$(0\mathrm{.}9$ of proof strength$)$ and the fasteners are lubricated.

e$.$ Determine the factors of safety guarding against yielding n$\_($p$),$ overload n$\_($L$),$ and joint

separation n$\_(0).$

Answers: