Process to evaluate lattice tower wind rating
Process to evaluate lattice tower wind rating
(OP)
I am looking at doing engineering calculations on lattice towers. I have read through TIA-222-G and believe I understand what needs to be done in order to verify the tower is safe to a specific wind load. Can someone verify that my process is correct?
1) Determine max wind speeds based on TIA-222-G or local jurisdiction requirements.
2) Calculate wind loads on tower using equations / process defined in TIA-222-G.
3) Create model of tower for FEA analysis.
4) Apply loads calculated in (2) to tower model. (Ensure dead loads are included in model.)
5) Compare maximum stress from FEA to max stress of tower material / guy wires / etc. If max stress is less than tower material rating, we're good to go.
Of course, that assumes I'm not concerned with earthquake loads (I'm not right now). I would have to do the same process with ice loads to compare tower under icing conditions.
1) Determine max wind speeds based on TIA-222-G or local jurisdiction requirements.
2) Calculate wind loads on tower using equations / process defined in TIA-222-G.
3) Create model of tower for FEA analysis.
4) Apply loads calculated in (2) to tower model. (Ensure dead loads are included in model.)
5) Compare maximum stress from FEA to max stress of tower material / guy wires / etc. If max stress is less than tower material rating, we're good to go.
Of course, that assumes I'm not concerned with earthquake loads (I'm not right now). I would have to do the same process with ice loads to compare tower under icing conditions.
Cedar Bluff Engineering
http://cedarbluffengineering.webs.com






RE: Process to evaluate lattice tower wind rating
2b) Apply appurtenance loads to tower.
2c) Account for shielding effects for tower.
2d) Evaluate icing loads on the tower to see if they have the potential to control the design (with a reduced wind load).
3b) Make sure you account for non-linear geometric effects in analysis i.e. P-Delta effects. These are much more likely to have a significant impact on the design of a communications tower because they are so much more slender than typical building or idustrial structures.
5b) Capacity is not just based on material rating, but on member behavior. Local Buckling of a cross section, member buckling or overall tower buckling.
RE: Process to evaluate lattice tower wind rating
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