Extra Problem: $1\mathrm{.}7\mathrm{.}11$

$1$

Steel riser pipe hangs from a drill rig located offshore in deep water $($see figure$).$

Separate segments are joined using bolted flange plates $($see figure and photo$).$

Assume that there are six bolts at each pipe segment connection. Assume that the

total length of riser pipe is $L=5000ft$; outer and inner diameters are $d_2=16in.,d_1$

$=15i{n}^2$; flange plate thickness is $t_f=1\mathrm{.}75in.$; and bolt and washer diameters are $d_b$

$=1\mathrm{.}125i{n}^2,d_{}=1\mathrm{.}875in.$

$($a$)$ If the entire length of the riser pipe were suspended in air, find the average

normal stress in each bolt, the average bearing stress ${}_b$ beneath each washer, and

the average shear stress through the flange plate at each bolt location for the

topmost bolted connection.

$($b$)$ If the same riser pipe hangs from a drill rig at sea, what are the normal, bearing,

and shear stresses in the connection?

$($Obtain the weight densities of steel and sea water from Table $1-1,$ Appendix I.

Neglect the effect of buoyant foam casings on the riser pipe$).$