Development and experimental validation of smartphone-based tools to assess mechanical tension forces in guy wires of transmission towers

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Steel overhead towers are among the critical components of Hydro-Québec's extensive power transmission network. The tension within guy wires supporting power transmission steel lattice towers has to be regularly verified to ensure safe operation and adequate structural performance. The main objective of this research project is to develop and experimentally validate a quick, reliable and rigorous technique to measure the tension within guy wires using smartphones. Most promising available procedures for assessing tension forces within cables will be identified and applied to actual case studies of guyed lattice towers. Finite element models of guyed lattice towers will be built and used to perform dynamic analyses to evaluate the influence of most critical parameters contributing to wire tension force. Two types of smartphones will be selected depending on the operating systems (OS) and the programming environment. They will be used to implement analytical formulations for estimation of tension force in vibrating guy wires based on measured acceleration data. The tension force within guy wires tested in the laboratory will be assessed. The smartphone will be attached to the guy wire using a fastener designed specifically for this purpose. The acceleration time histories recorded by tri-axial accelerometers and smartphone during free vibration of the guy wires will be compared to assess the accuracy and potential limitations of the smartphone built-in accelerometers. The smartphone applications developed will be used to extract frequency data and predict actuator-controlled tension forces within the tested guy wires. The tension force in the guy wires of selected guyed towers will be assessed in-situ using the programmed smartphones and validated against load cell measures. User interfaces that enhance effective and quick operation of the developed smartphone applications will be programmed and tailored to the needs of end users. The proposed vibration-based technique will be implemented into Hydro-Québec's asset management programs. A user manual describing the smartphone application developed and a step-by-step illustration of its correct and effective use for different categories of guy wires will be provided.