(c) Influence line for shear in panel deFIGURE 49- Assume a load position, and determine whether Vde increases
or decreases
Consider that load 1 lies within panel de and the remaining loads lie to the right of this
panel. From the slope of the influence line, ascertain whether Vde increases or decreases
as the system is displaced to the left. Thus dVJdx = 5(-7/20O) + 45(1/200) > O; /. Vde in-
creases. - Repeat the foregoing calculation with other assumed load
positions
Consider that loads 1 and 2 lie within the panel de and the remaining loads lie to the right
of this panel. Repeat the foregoing calculation. Thus dVJdx = 17( -7/200) + 33(1/200) <
O; .*. Vde decreases.
From these results it is concluded that as the system moves from right to left, Vde is
maximum at the instant that load 2 is at e.
(b) Load system(a) Pratt trusspanels