Strain Gauge-Based Quantitative Monitoring During Prototype Testing of Transmission Towers

Full-scale prototype testing remains the definitive means of validating transmission tower behaviour, yet traditional evaluation depends largely on qualitative observation of deformation and failure patterns. This study introduces a quantitative, data-driven methodology that integrates real-time strain gauge instrumentation into the prototype testing process for improved diagnostic precision. A total of five towers—one 400 kV Quad and four 765 kV DA, DB, DC and DD configurations—were instrumented with 38, 70, 18, 12 and 19 strain gauges respectively, covering 30 structurally critical members. Predominantly 1-way gauges were used to monitor axial strain, supplemented with 2-way and 3-way gauges at complex joints where principal strain directions could not be predetermined. Each member was assigned a threshold strain limit based on design forces with a 10% safety margin, enabling real-time overstress identification during testing. Three threshold alarms were triggered in the 400kV DD and 765kV DA tower; however, subsequent inspection revealed no deformation, and these members were monitored closely for the remainder of the test.