GEO-Instruments Application Notes

Geo-Instruments was contracted for the Ulink I-5 undercrossing project: U215. The U215 Contract is part of a larger plan that will eventually link the University of Washington to SeaTac airport, through downtown Seattle. U215 involves tunneling under inter-state I-5, a major artery in Seattle. I-5 was constructed in the early 1960´s and retaining structures supporting road cuts through the Seattle hills are critical to public safety. Enhanced systems were proposed and installed by Geo-Instruments. In turn, Geo-Instruments had the duel honor of being the first to install an automated pulsed laser scan for near real time structural monitoring in the world, and the first WiSe wireless sensor network in North America.

This highway was unable to be closed for reconstruction since this six-lane parkway carries approximately 175,000 vehicles per day through the lower city, and approximately 150,000 vehicles per day through midtown. Thanks to Geo-Instruments near real time monitoring instrumentation and technology, this active highway is currently being monitored during reconstruction to provide an early warning system and ensure the safe passage of these thousands of vehicles.

In November 2008, a barge battling against strong river and tidal currents, laden with over 950 tons, with only 1 foot of clearance between piers, collided into the bridge pier. The collision resulted in damage to the bridge pier, misalignment of the swing span and the inability to close the bridge properly. This created questions about the load capacity of the bridge and its ability to safely support the heavy volume of traffic. This vital link between two communities was closed by the Mass. Highway Engineers due to these public safety concerns. Engineers designed a series of tests to determine the structural integrity and load capacity of the bridge. The test called for GEO-Instruments to install and monitor 6 vertical and 4 horizontal beam sensors, 2 vibration monitors and a lateral load test.

New York´s MTA´s East Side Access project will connect the Long Island Rail Road´s (LIRR) Main and Port Washington lines in Queens to a new LIRR terminal beneath Grand Central Terminal in Manhattan. The project requires tunneling across the upper east side of Manhattan Island in New York and down Park Avenue to the existing Grand Central Terminal. In order to monitor the effect of the tunneling operations on existing high value real estate above the tunnel, the project designers specified traditional multiple position borehole extensometers (MPBX) for tunnel alignment cross sections.