Need Help with Telephone pole design

[pushindirt]

Currently, I am supervising a DOT project in NJ. The Dot's engineer has designed the use of wooden poles for use as temporary traffic signal poles. Here's the catch - there's no mast arm on the pole, only the double pedestrian walk lights at 8 foot from the ground.
Here's the problem -
1. There's only 20 pounds of weight generated by these two lights at 8 feet off the ground.
2. The pole is set 10 into the ground, backfilled with concrete;
3. The overall height of the pole out of the ground is 25 feet or greater;
4. There is only 2-10 gauge power wires, a guy cable for the wir to hang on, and 3- 14 guage wires hanging from the same guy, attached by ties.
5. The span is as great as 50 feet to the steel pole on the other sidee of the road.

The DOT engineer has designed a pole that has a diameter of 16 inches or greater that is need in order to handle the load. HERE'S THE KICKER - They are requiring a guy wire to be attached to a ground anchor at some distance behind the pole.
Now I am no PE, but my past experience with 20 pounds of vertical load, and 30 pounds (estimated) of wire load hanging across an intersection at 16 feet up a 25 foot pole - the size of the pole doesn't nee to be this big, nor is the use of a guy required.

Can anyone help??? Is there a chart that tells the size of the pole and what load is available for that size? Is there a book that could help me quickly calculate the loading available??

 

[DaveVikingPE]

How about wind loads on the pole?

A great general source of information (with some tables) is the Lineman's and Cableman's Handbook published by McGraw-Hill.

 

[pushindirt]

Wind Loads... Well the poles are installed in Newark, NJ, and I would say the worst wind is probably on the order of 20-30 mph gusts.

Do you think you can help??
I will look into the book you have suggested.
Sam.

 

[DaveVikingPE]

Compute the wind loads using ASCE-7.

Lineman's and Cableman's handbook gives a rule-of-thumb regarding depth of utility poles of:

10% X pole height + 2 ft = min embeddment depth, with a minimum of 5 ft. REMEMBER: it's rule of thumb. If you know the soil conditions (rock conditions?) you can design a rock socket/soil socket using several methods.

Lineman's and cableman's also has a chapter on guying poles that's pretty interesting.

 

[Trussdoc]

Ahh---New Jersey, land of toxic waste and lawyers! A temporary utility pole falling in downtown Newark would create a major catastrophe (or a bonanza, if you're a personal injury lawyer) Hence the conservative approach!

The issue of wind loading in NJ has been a bone of contention for a few years now, and the Department of Community Affairs (DCA)waffled for a long time as to what the wind design speed should be. Definitely, Newark is not 20 to 30 MPH, closer to 80 or 90, with a reduction factor for Exposure A (urban).

I agree that 16 in. diameter seems excessive; a lot hinges on whether the pole is going to remain up during the winter, when ice can form on the wires (love those jersey winter wonderland ice storms)

 

[stuff9]

take a look at

http://www.osmose.com/utilities/restoration_upgrading_ocalc/o-calc/overview/

they can mail you a demo disc to play with...

nice software

 

[boo1]

For a free link to Specification for Wood Poles see:

http://www.usda.gov/rus/electric/bulletins.htm