d. Category 4. Prevent mass detonation of explosives as a result of
subsequent detonation produced by communication of detonation between
adjoining areas. As in the case of Category 3, minimum separation distances
between structures in Category 4 can be reduced when they are designed to
totally contain the effects of an accident (blast pressures and fragments).
EXAMPLE PROBLEM - Moment Area Method
Find the time to maximum displacement for the load and
resistance shown below if XE < Xm < X1, and the duration
of the blast load is less than tE.
Construct a plot of p/m and r/m.
Calculate the displacement, XE of mass at time tE.
Express tE in terms of XE.
Determine the net area up to the time t = tm.
time is when the new area under curve is zero.
The load and resistance diagrams shown in Figure 5.