Quality of Residential Light Poles

Introduction:
While many may not realize the need is as strong as it is, the demand for high quality light poles is as high as ever. This is apparent with any search for a residential light pole. A walk through your local hardware store will reveal a selection of hundreds of different designs from numerous manufactures. On a larger scale a search on the internet can be done to bring up thousands of different choices for a buyer considering making a purchase. For garden and pool areas shorter lights closer to the ground with less bulbs are available. For front yards and walkways there are taller poles with numerous lights around the top of the pole that are better suited for lighting larger areas. Searching the patent office for “light pole” brings up 28 different patents for all different aspects of light poles. These patents range from different mounts and bases all the way to different ways of reflecting the light. Even locally the trend for classic lighting by poles has become popular. To add a sense of illumination to both front and back yards many residents in the area have been adding light poles. Even closer to the Texas Tech University campus in the Overton area the influence of light poles can be seen. In fact, design guidelines for this area call for a light pole every 75 feet along walkways and 200 feet along roadways by the completion of construction. The importance of light poles spreads overseas as well, as the Weixing Lighting Co. Ltd. Exports products to North America, Europe, Southeast Asia, and the Middle East. With so many different products available it is hard to deny the need for an effective and functional light pole. When designing a light pole to be added to the market there are some issues more important then others. Our specific light has three lamps at the top of the pole, each at 120 deg off center. Each one of these lamps is 20 cm wide and 28 cm tall. With such a large side area created by the light covers the effective moment about the base of a pole can get very large. A recent 2006 ASME study done on failures of aluminum alloy light poles during winter storms showed how damaging wind can be. “In recent years wind buffeting-related fatigue has been indicated as a critical issue on these systems and slender steel poles.” While a residential light poll is much smaller then a highway light pole, its dimensions would still classify it as a slender pole. A volume of structural engineering papers claims that, “residual stress plays an important role in the behavior of welded structures subjected to cyclical loading.” Wind forces are a perfect example of cyclical loading because both the magnitude and the direction are constantly changing. All stresses incurred in the pole have to be supported by the bases. It could be for this reason a residential landscape and lighting design website claims “mounts and bases are among the more important hardware elements of any commercial light pole”. If the mount fails, then effectively the light pole as a whole fails because it no longer meets its design requirements. A poor base can make the light pole nonfunctional as the light is no longer evenly spread out. For those looking for an even balance of light spread throughout the area, this could be an extreme problem depending on the lean of the pole. A weak base can also pose a safety concern as electric wires running up the pole can be exposed. In some extreme cases of highway light poles there have been reports of deaths by electric shock. While few residential light poles have enough electricity running through them to pose serious threat, the possibility is still there. Lastly, a failing base makes a light pole look unattractive. A light pole improves the look of a yard or garden by both the addition of light as well as the pole itself. A light pole with a significant lean to it can ruin the overall look of the area by giving it not only a cheap but also unkempt appearance.
After looking more into this particular light pole, the objective of this project was easy to define. A simple design and implementation of a light pole support system. This can be accomplished in any way we chose, as long as the end result supports the weak base of the light pole. In addition to supporting the light, the support system needs to be easy to make and simple to add to the pole. Ease of installation will help the product sell. While this might seem simple, there are many variables to consider in the design that will affect the end result. Strength, material, cost, and machining ability are just a few of these variables. With the objectives clearly defined, the scope of work was easy to see. Research and design of numerous solutions to strengthening the light pole will be required this semester. After coming up with the new designs, an analysis of each system and recommendation of the best solution is will be needed. Finally a prototype of the recommended solution will be required by the end of next semester. The deliverables are also straight forward for this project. All the research needs to be compiled and organized after completion of the project. All the final findings will need to be outlined in a report that will be delivered to the sponsor at the end of the semester. By the end of next semester we will need to have a prototype built that can be used.