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ANDERSON & ASSOCIATES CONSULTING ENGINEERS, INC. <br />3902 VILLA SAN JOSE DRIVE, JACKSONVILLE, FLORIDA 32217 (904) 731·7978 Fax (904) 731-7771 <br />PERIMETER TRUSS <br />STRUCTURAL CAPACITY <br />C. Consider Lateral Stability (Global Buckling) <br />A3 = 2.945 in2 <br />Iy = 252.002 in4 ry = 9.25 in <br />Determine Span where Lateral Stability becomes a consideration: <br />Member Bending Capacity is controlled by the Weld at the Chord to Vertical and HorizontalMembers <br />Pew = 5.407 kips Fa:= <br />Pcw <br />A1 <br />Fa = 7.343 ksi <br />Now determine allowable axial stress for various unbraced lengths <br />51000 Fa(L)-Al-dx·2Fa(L):= - ksi Ma(L):=ft-kips Fa(600) = 12.121/1\2 12 50 ft Ma(600) = 41.65 <br />Fa(612) = 11.651 51 ft Ma(612) =40.033 <br />Fa(624) = 11.207 52 ft Ma(624) =38.508 <br />Fa(636) = 10.788 53 ft Ma(636) =37.069 <br />Fa(648) = 10.392 54 ft Ma(648) = 35.708 <br />Fa(660) = 10.018 55 ft Ma(660) = 34.422 <br />Fa(672) = 9.663 56 ft Ma(672) = 33.203 <br />Fa(684) = 9.327 57 ft Ma(684) =32.049 <br />Fa(696) = 9.008 58 ft Ma(696)*= 30.953 <br />Fa(708) = 8.705 59 ft Ma(708) =29.913 <br />Fa(720) =8.418 60 ft Ma(720) =28.924 <br />SummarY: <br />Lateral Stability (Global Buckling) is not a consideration for the Perimeter Truss at spans under60 feet <br />Mew = 25.231 ft-kips may be used for Spans up to 60 ft. <br />D. Determine Truss Shear Capacity <br />- 2" Dio. (18" Woll) <br />CD <br />t391&: Shear1 Capacky is <br />allowable force on <br />determined by <br />maximum <br />1st Diagonal.0\.1 147\1 48.9' <br />1 <br />- 112" Dia. (18" Wall)