<p><p><strong>References:<br></strong><em>Sabatini et al. (2005)</em></p><p><strong>Method Summary</strong></p><p>Axial displacement can be measured using telltales at discrete elevations in a micropile after installation or during load testing. Telltales are metal or fiberglass rods anchored in the micropile grout at the tip of the rod at various elevations. The remainder of the rod is sheathed in order to allow free movement of the micropile (Sabatini et al. 2005). The free end of the telltale protrudes above the soil surface, by which movement of the telltale can be measured. Movement of the telltale is an indication of axial displacement of the micropile at the location where the telltale is embedded. Multiple telltales can be installed in a micropile to provide an idea of the micropile’s axial displacement with depth.</p><p><strong>Accuracy and Precision</strong></p><p>Telltales can be relied upon to indicate how the micropile is moving beneath the soil surface. However, care must be taken to avoid damage to the telltales during micropile installation as this will provide inaccurate information about axial displacement with depth. Even when installed correctly, telltales can be difficult to interpret.</p><p><strong>Adequacy of Coverage</strong></p><p>Telltales provide a reasonable assessment of the micropile’s ability to sustain a service load with minimal displacement with the adequacy of coverage that all load tests provide.</p><p><strong>Implementation Requirements </strong></p><p>The installation of telltales requires considerable experience in order to avoid damage and erroneous results.</p><p><strong>General Comments</strong></p><p>Telltales provide a reasonable assessment of the load distribution over the length of the micropile. Telltales are very susceptible to construction damage and should be treated with great care and suspicion. Because of this, telltales are not commonly used in micropile projects.</p></p>