Design Steel Pole: 3 Segment, 50ft, Max Wind 110mph

[AnnieFatima]

Homework Statement

I need to design a steel pole in 3 segments.The base segment needs to be
25 ft high , the second segment needs to be 15 ft and the third one 10ft high.So that when mounted on top of one another their total height will be 50 ft.Their diameters need to be within 1.6-7 inches.

The load on the pole will be a 40 kg cabinet at 5 ft , a 1kg equipment at 10ft ,a 5.4 kg equipment at 35 ft, a 3.6 kg equipment at 40 ft and a 2kg light at the top height of 50 ft.The area where the pole will be mounted has a maximum wind speed of 110mph and there will be no snow.I need to calculate the loading on the pole and then calculate the required diameters of the segments and the steel gauge/metal thickness.

Can anyone please help me with this.

Homework Equations

The Attempt at a Solution

Going through the internet a solution that I came up with is to have a diameter of 6 inches and gauge 7(0.18 " /4.76 mm) sheet for the base 25 ft section.
A 5 inches diameter and gauge 9 (0.15"/3.96mm) sheet for the second segment.
A 4 inches diameter and gauge 9 (0.15"/3.96mm) sheet for the third segment.

But I can not justify if this will bear the load and all.

Also The segments will be joined to each other through plates and the pole will be joined to the ground through a base plate,anchor bolts and a foundation.

 

[Nidum]

https://www.google.co.uk/search?q=d...bIUCh2q7Q6u#tbm=isch&q=designing+aerial+masts

https://www.google.co.uk/search?q=d...h2q7Q6u#tbm=isch&q=free+standing+aerial+masts

(1) Decide whether mast is going to be free standing or supported with guy wires .

(2) Masts made in pieces are notoriously difficult to join together . You will need to design very strong connections .

 

[AnnieFatima]

Free standing it is, no guy wires can be used.

 

[Nidum]

(1) When dealing with wind speed loads the sizes of the equipment boxes will matter - do they present a large or small area to the wind .

(2) Also by how much are they offset relative to mast - are they close to mast or on brackets with significant leverage action .

(3) There are tables available for estimating wind loads .

When you have your loads sorted out you will need to prepare a bending moment diagram . From that and dimensions of tubes you will be able to calculate stresses and deflections .

 

[AnnieFatima]

Sorry, but what do you mean by a mast.As for the equipment the largest one is the 600mm X 760 mm which is the cabinet.The rest of the equipment are lights and buzzers which have a small area.

I have made a rough bending moment diagram and have the moment at the ground-line. I don't know how to proceed further and find pole dimensions.

 

[Nidum]

A long vertical pole is often called a mast because of the similarity to a ships mast . It's just common usage . I'll use the pole word from now on .

Can you show us your bending moment diagram ?