Column buckling of truss structure
Column buckling of truss structure
(OP)
How do you handle Euler column stability in a truss type tower? Examples would be lattice-type crane boom or antenna towers. Design of individual elements wouldn't be a problem, but how do you show that the overall structure won't buckle in classic column failure?






RE: Column buckling of truss structure
RE: Column buckling of truss structure
(1) Calculate the buckling load using the Euler method, either by hand or by FE. The buckling equation is given here This gives you the critical load to cause buckling of the structure. You can also do this in FE if you have access to a code.
(2) Carry out a non-linear buckling analysis. Expensive.
------------
See FAQ569-1083 for details on how to make best use of Eng-Tips.com
RE: Column buckling of truss structure
Using basic principles, you can calculate the centroid, and moment of inertia of the axial members in your section, and use this to approximate an effective radius of gyration, then check this as a (built-up) column.
I disagree with rb1957- you can certainly get global column buckling even if your truss elements do not buckle locally.
tg
RE: Column buckling of truss structure
RE: Column buckling of truss structure
RE: Column buckling of truss structure
RE: Column buckling of truss structure
RE: Column buckling of truss structure
Wasn't a famous bridge collapse around the turn of the century during erection in Canada the result of said buckling? Wasn't the cause the neglect of global shear deformation (Essinger's equation)? Sorry no time to research and see if memory serves correct--have to get back to work.
RE: Column buckling of truss structure
RE: Column buckling of truss structure
htt
Apparently, "built-up" columns may be approximately analyzed as homogeneous columns, but the shear effect causes the above to happen, which in standard formulae is neglected. The bridge at the time was to be the longest span in the world. I never see anyone calculate anything anyways, just reams of illegible computer output. It seems policy and perception find software superior to understanding, it makes everyone feel warm and comfortable. Must be done right if the software was expensive and created by PHD's. It's just so pretty and professional.