Search the Community

Hello there SEpakistan, Im designing a long span structure for roof, this just an alternative instead of using PEB. The span of structure is 53m and its monosloped. I know in this case gravity loads will govern. DL = 30 kg/m2 and live loads 58 kg/m2. I tried to model this structure in staad pro with lattice girder with bottom and top chord using T section, and vertical and diagonal with double angles. Because the top and bottom chord will be continous when jointed with vertical and diagonal member, so i just add the truss spec to the diagonal and vertical member as a truss. When i run the analysis, the top chord and bottom chord behave just like a beam on the outer fiber. near the support the top chord got tension forces and bottom chord got compression forces, and on the mid of span the top chords is in compression and the bottom chord is in tension, i modeled this a rigid to column. My question is how do i apropriate design this lattice girder? Did i do it wrong? I need some explanation on how this kind of system works. Thank you. Regards