Utilizing Strain Gages to Estimate Lateral Load Test Displacement Vs. Depth-Video

Video Transcription

Video Summary

The presenter described using strain gauges already installed for bidirectional load tests to obtain additional data during lateral pile testing. Opposed gauges measure tension and compression; their difference estimates curvature, which can be numerically integrated to calculate pile rotation and lateral displacement. Comparisons with shape-accelerometer arrays on several projects showed that this approach produced reasonable displacement profiles, although boundary conditions and a constant integration offset needed consideration.<br /><br />The talk also highlighted that pile-head displacement alone may be insufficient: measurement height and pile-head rotation can substantially affect results. The presenter recommended specifying inclinometers where practical, or monitoring existing strain gauges during lateral tests, with gauges aligned to the anticipated load direction. Strategic gauge placement can also capture changes in soil layers. Attendees discussed concrete cracking, gauge installation, and cage rotation; the presenter noted that misalignment can be addressed approximately, but is difficult to prevent in the field.

Keywords

strain gauges

lateral pile testing

pile rotation

pile head displacement

inclinometers

soil layers monitoring