Wood pole alternative design challenge: it’s the kind of challenge that will completely change the way students see such a commonplace piece of engineering
Published in: The Technology Teacher
Date: 2/1/2008
By: Roman, Harry T.
Introduction
Everyone knows what they are, the wooden utility poles that hold up power lines, telephone lines, and cable TV wires. They are everywhere and aging rapidly. Probably the average life of utility poles now in service is easily over 40 years. This important resource now requires increasing maintenance and care to restore and preserve them in place. Wood, like all natural products, has a finite lifetime. In this challenge, your students will seek alternatives to traditional wood poles.
The Challenge
Students will investigate and develop viable alternatives to wood poles. They will:
* Identify new methods to treat the traditional wood poles that are environmentally clean and increase their average service life.
* Propose perhaps using completely different kinds of natural materials or tree species never used before. OR
* Develop a completely new pole concept using synthetic, recycled, or man-made materials.
This is not a trivial problem, and requires multidimensional thinking and interdisciplinary problem-solving skills.
Getting Underway
There are probably close to 100 million wood poles in service across the country, with various wood species used locally depending upon ground conditions and insects present. The first thing students need to understand is how wood poles today are treated for use. This information is available from:
* Utility companies
* Libraries
* The Internet
* Utility industry regulatory agencies
* Pole manufacturers
* Industry experts
Wood species that are used can vary as well. This needs to also be researched and can generally be found from the same sources as initially listed above. The electric utility industry, which owns most of the poles, has a national research arm in California known as the Electric Power Research Institute that can be reached at www.epri.com. Here much information about wood poles can be gained. There are also colleges across the country that have forestry programs, and generally within these programs are professors who are experts in wood poles used in industry. This is another resource that should be pursued.
Much concern has been expressed in the past about how creosote and other petrochemicals have been used to treat the poles and preserve them for long life. Other treatment processes have been proposed, and new types of poles have been experimented with over the last decade or so. Might there be another way to treat the poles to preserve them without using dangerous oil-based chemicals that could leach out of the poles and into the nearby soil? A first order of business is a solid understanding about how poles are made. This is task number one for the students.
Another important step is a complete understanding of the costs associated with wood poles. Let’s make a list to get things started here:
* Bare cost of the timber
* Treatment and preservation costs
* Shipping and stocking the poles at the utility company
* Installing the poles and attaching equipment
* Maintaining the poles and repair costs
* Removal and disposal costs
Any changes to traditional pole technology by substituting new types of poles should be economically better than the existing pole technology or promise radically better improvements over the long term. Engineers pay attention to the costs of solving a problem. More and more concern with environmental issues and disposal costs for poles is creeping into the financial equation for pole budgets at companies.
Utility workers can reach up into the poles and wires in one of two ways: 1) bucket trucks provide aerial access, or 2) poles are climbed using spiked boot attachments.
Any changes that are evaluated may have to accommodate both methods of gaining access, or there must be reason to believe that perhaps traditional pole climbing using spikes may eventually be phased out. Changes like this may vary from utility to utility and across geographical areas. For instance, where poles are not near roads or road access, bucket trucks may be useless and workers will climb the poles using the old spike method. For urban and suburban areas, bucket trucks may be just fine. Local conditions may dictate where wood or nonwood poles are used. Nonwood poles may be impossible to climb using spikes, and this may be a constraint in which nonwood poles can be used. Students should be mindful of this and other such constraints as they research the area for information and experience.
Don’t hesitate to invite an electric utility company engineer in to talk about wood poles, or maybe arrange a visit to a company site to see the poles. Maybe your students can actually see a wood pole installed or repaired in place, and gain perspective about the complexities involved. Nothing would beat such an experience and being able to interview engineers and technicians who perform this work all the time. Utility companies are usually quite amenable to working with schools within their community. This is a superb source of firsthand information for the challenge.
There should be lots of latitude given to students in this challenge; and they can work in teams or individually as conditions justify. It’s the kind of challenge that will completely change the way they see such a commonplace piece of engineering like wood poles–and give them the perspective to see engineering principles and techniques in many other mundane, taken-for-granted objects. A pole is a whole lot more than simply a dead tree. Have fun!
Harry T. Roman recently retired from his engineering job and is the author of a variety of new technology education books. He can be reached via email at htroman49@aol. com.