Settlement Solutions
Designed liquid level settlement system to measure the differential settlement
Scroll Down
The Challenge
- Construction of new taxiway required contractor to excavate 4-5 feet to depth of saturated soil
- Settlement was observed prior to construction on one section of the taxiway
- Challenge was to monitor potential settlement as construction progressed
The Massachusetts Port Authority (Massport) operates Boston’s Logan International Airport. In the last decade, Massport and its airline partners have invested more than $4.4 billion to build a new runway, roadways, and terminals. The construction of Taxiway M was commissioned in 2008 as one of several projects to help with safety at the airport after a series of incursions occurred.
The taxiway was being built to decrease the number of runways that planes must cross and to reduce ground delays. Logan airport is built on filled land in Boston Harbor. Runways and taxiways are approximately 15 feet above sea level. Ground water levels in the filled soil are affected by the daily tidal fluctuation.
The Solution
Construction of Taxiway M required the contractor to excavate approximately 4 to 5 feet of the filled material to a depth where the underlying soil was saturated. Subsequent to construction of one section of the taxiway, settlement was observed which required reworking the constructed area. To avoid this condition in future construction, the contractor turned to Geocomp to devise a method and system to monitor potential settlement as construction progressed. Geocomp’s challenge was to design a liquid level settlement system to measure the differential settlement between two points.
The system was comprised of three vibrating wire liquid level settlement sensors, installed at the bottom of the excavation, and perpendicular to the taxiway centerline. As backfilling and compaction took place, the sensors measured the changes in pressure. The sensor data was recorded automatically by a Geocomp data logger and transmitted in real-time to Geocomp’s web-based monitoring system, iSiteCentral®.
Related Projects
