Transmission line foundations are designed to support and stabilize a tower, such that the structure is firmly anchored into the ground and can effectively resist the transferred forces resulting from the applied load cases under consideration. Over time, however, the structural integrity of these foundations can be compromised in a number of ways that could lead to a significant and dangerous weakening of their load bearing capacity. Possible causes include environmental factors like severe weathering, or human factors like poor workmanship during construction. This report will present the methods and rationale developed to provide a visual inspection and assessment of concrete foundations for transmission lines. The method was developed for and used on three lines in Iceland and six in Norway, providing an effective indication on the overall condition of individual foundations. Using the proposed assessment methodology, it is possible to describe the current status of the foundations and to monitor the time-based deterioration process by determining a baseline condition. This thereby informs effective decisions concerning further investigations and any requirement for repairs. Included in this report is direction on the recording of results along with interpretation of those results. The demonstration of the methodology is based on photographic records from previous assessments, which show what to look for and how to define the severity of the foundation deterioration. The methodology in this report is designed so that a non-technical person can carry out the work, even though the final conclusions should always be carried out by a specialist.
Concrete Foundation, Condition Assessment, Foundation Damage, Transmission Line Foundations