1.    

The computer programmed curves in the graph below, plotted for rib thicknesses equal to 60 percent of wall thickness, are presented as an aid in calculating maximum deflection of a ribbed structure. WD Wa Wall thickness ratio 10 9 8 3 0 0 1 2 3 4 H W 2/- 5 d 0.03R Height of rib ratio A 6 B B 0.6 W 7 A H W Wo 8 9 0.62 1.0 1.25 1.87 2.5 3.75 5.0 6.25 7.5 10.0 12.5 15.0 20.0 25.0 37.5 50.0 75.0 150.0 10 Base width