Abstract:
This article presents a case study with an analysis of field and numerical tests of helical pile foundations used for tensile loads of guyed towers of a transmission line in northeastern Brazil. This article is a continuation of the work presented by the authors in 2022. After analyzing the problems, foundation reinforcements were proposed using a metal beam coupled to two new foundations executed in parallel to the existing pile. We know that work on a transmission line involves many challenges, as the geotechnical properties can change during the execution of the foundations. The helical piles showed geotechnical failure after 5 years of installation, with a fall in the structure causing the shutdown of the transmission line. All site data, Nspt soil tests, and soil laboratory tests (characterization, densification, triaxial) were analyzed, verifying variations along the foundations. Additionally, field tests were carried out in real magnitude on the foundations for failure analysis. In the execution of the reinforcements, new tests were carried out on the reinforcement piles and the results were compared with those performed at the time of implementation of the enterprise. Subsequently, a numerical analysis was carried out in finite elements of the reinforcement set composed of metal beams and other devices that will also be presented. The problems encountered in the execution of these foundation reinforcements for each location will be presented. The logistics of carrying out the reinforcements will also be presented, taking into account that the Transmission Line was energized, and its shutdown would be very economically harmful.