Monitoring I-375 for Settlement
I-375 was closed for two nights to allow installation of the instruments.
Four AMTS units provided continuous monitoring for settlement of the road surface and bridge during installation of an underground power transmission line.
Project
The project involved horizontal directional drilling below I-375 to place an underground power transmission line.
The highway and the roads crossing above the highway were to remain open to traffic for the duration of the project. To mitigate risk, the contractor opted for intensive monitoring of the road surface and bridge pillars.
Monitoring Requirements
Measurements were required at 15 minute intervals. At each interval, the system had to calculate settlement, check for alarm conditions, and update views and graphs on a project website.
Alarm thresholds were set at 0.13 and 0.25 inch, with stop-work set at 0.36 inch. Texts and email alerts would be sent if these thresholds were exceeded.
Implementation
GEO installed 24 road prisms on highway, 16 L-bar prisms on the bridge, and 20 control prisms. Four AMTS systems were needed to meet the 15-minute requirement.
The monitoring system collected baseline data for one week, monitored construction activity for two weeks, and then monitored for any post-construction effects for a final week.
Work performed with Corby Energy Services and Metro Consulting Services