The science of pole selection: Reliability-Based Design enables utilities to compare strength and loading characteristics of concrete, wood, steel and fiberglass poles

摘要

Construction in any industry is often guided by empirical results, but calculated designs are always preferred over experiential values. In building transmission and distribution lines within the power industry, the preference is no different. However, providing better designs is challenging when most U.S. states only require the lines to meet the minimum safety requirements of the National Electric Safety Code (NESC). The NESC was never intended to serve as a design code. Nevertheless, it has become the de facto standard by which many lines have been designed and constructed. One problem with the NESC is that the specified design load and strength factors do not have a strong theoretical foundation. Instead, these factors are primarily based on "successful" experience. As such, some utilities find the NESC requirements to be too conservative, while others feel they are not conservative enough and have seen fit to develop loading criteria to supplement the NESC requirements.