calculate transmission monopole

[haihiha]

We want to calculate above power transmission monopole. What is the accepted deflection? (Percentage of height). Where this deflection being mentioned (described) in ASCE Manual 72 ?
Can you help me.
Thank.

 

[MPaul]

Greetings:
It is understood different designers and manufacturers use different criteria to limit deflections. IE tangent pole ~ 10-12% of height, deadend end structures 2-3% or there abouts. This includes deflections due to foundation displacements and foundation rotations. This probably is not very helpful, but perhaps others can provide more definitive information.
M. Hansen
Seattle Utilities

 

[hnamiranian]

There is a rule in DIN VDE 1985 for deflection limitation :
1- (L&H) suspention towers : 4.5% of height
2- Tension and D.E. towers : 2.5% of height

But there is no limitation for deflection in ASCE MANUAL No. 72 and 52.
H. Namiranian

 

[mtroche]

But.. what is the recomended deflection for a concrete pole? I am working with them and I don't want to make my design too expensive neither too frightening to the people looking the poles too inclined, although it's safe.

Thanks for any help.

 

[Focht3]

In populated areas, it's not unusual to limit pole rotation to [½][°] and groundline deflection to [½] inch -

Of course, you will need to engage the services of a qualified geotechnical engineering firm to develop these predictions using p-y curves to model the soil. And you can generally forget the "rules of thumb" on pole embedment i.e. 10% of pole height + 3'. Embedment will have to be calculated based on the actual soil properties...



Please see FAQ731-376 for great suggestions on how to make the best use of Eng-Tips Fora. See faq158-922 for recommendations regarding the question, "How Do You Evaluate Fill Settlement Beneath Structures?"

 

[MikeDB]

Deflection limitations for concrete poles with unfactored loads should be less than steel or wood poles as the concrete cracks. If you limit pole stresses based on the capacity at first crack, that may be the limiting factor rather than defelection.