Design of Beams for Pressure-Time Loading.
Design a purlin or girt as a flexural member which responds to a
(1) Pressure-time load, P-T.
(2) Design criteria [theta]max and [mu]max.
(3) Span length, L.
(4) Beam spacing, b.
(5) Support conditions.
(6) Properties and type of steel.
(1) Determine the equivalent static load, w, using the
following preliminary dynamic load factors:
0.8 for a non-reusable
1.0 for a reusable
w = DLF x p x b
(2) Using the appropriate resistance formula from Table 5 and
the equivalent static load derived in Step 1,
(3) Select a member size using Equation (83) or (84). Check
the local buckling criteria of paragraph 3.a.(5) for the
(4) Determine the mass, m, including the weight of the decking
over a distance center-to-center of purlins or girts, and
the weight of the members.
(5) Calculate the equivalent mass, me, using Table 6-1 of
NAVFAC P-397 or Table 10 of this manual.
(6) Determine the equivalent elastic stiffness, KE, from
Table 7 of this manual.
(7) Calculate the natural period of vibration, TN, using