SEISMIC ANALYSIS OF MONOPOLE TRANSMISSION TOWERS

[WG]

WHAT IS CURRENTLY BEING USED AS FAR AS THE ANALYSIS OF MONOPOLES CONCERNING SIESMIC LOADING. TIA/EIA IS NOT VERY HELPFUL, AND SPECIFIC CODES, I.E. UBC/BOCA ARE NOT VERY APPLICABLE TO MONOPOLE TYPE STRUCTURES. ARE THERE EUROPEAN GUIDELINES FOR THIS???

 

[Qshake]

Because the monopoles are often proprietary products I would assume that the seismic (vibration) design of the pole is up to the manufacturer. It seems logical for the connections (unless they are specified by the manufacturer) to be designed by the enigneer as is the foundation. As such, this problems seems almost text book in the application of base shear. As for as any factors are concerned I believe that UBC had R factors for Non-building structures which include inverted pendulum type structures as well as a host of others. Distributed mass cantilevers are included so if you don't want to lump mass at the top...

 

[TowerPE]

TIA-222-G (Draft) contains seismic analysis provisions for all of the various types of towers. For poles up to 50 ft, you can use an equivalent static lateral force procedure. Above 50 ft you must use either modal analysis (spectrum response) or a time history analysis. Enough modes should be included to attain 85% mass participation. 222-G probably won't be out until the end of this year.