HGC has a keen interest in geotechnical instrumentation and structural performance monitoring. The principals have been involved in numerous instrumentation and field monitoring programs, and believe in combining and understanding of fundamental material behaviour with the site-specific feedback that instrumentation provides to develop economical solutions and increased reliability of design for our clients.
HGC has experience with the installation and monitoring of a myriad of equipment as well as the interpretation of the recovered data. The principals at HGC have experience with the following:
The Lennox Passage bridge was built in the 1970’s and consists of a three span structure with a central bascule lift span. Throughout it’s service life the bascule span has experienced problems jamming during high temperatures for which no long term solutions have been developed.
In August, 2015, the Harbourside team implemented a year long monitoring program to capture the full thermal cycle of bridge movements. The instrumentation deployed on the Lennox passage bridge consisted of 4 thermistors measuring bridge deck temperature, 4 LVDTs measuring girder elongation, and 8 tiltmeters which measure rotation of the bridge’s abutments and two piers. The monitoring was carried out using a remotely accessible data acquisition system recording measurements at 15 minute intervals. The monitoring program was combined with quarterly slope inclinometer readings at the east abutment and a detailed survey to help understand the overall soil-structure behavior.
The Principals of HGC have recently completed an embankment monitoring and staged construction analyses for the placement of the approach fills at the Little River Bridge in Lower Cove, NS. The replacement of the Little River Bridge required several meters of fill to be placed on normally consolidated marine sediments. Analyses showed that rapid placement of the fills would likely have resulted in slope failures of the approaches.
Working with the local department of transportation and the contractor, the staff of HGC carried out a monitoring program which included the installation of vibrating wire piezometers in the underlying marine sediments, settlement plates near the base level of the fill, and slope inclinometer casing extending through the underlying glacial till and bedrock. Monitoring the dissipation of excess pore pressures and settlements paired with geotechnical analyses provided a practical approach for scheduling completion of the fill placement, while maintaining reasonable factors of safety against slope instability. Monitoring of the slope inclinometers provided an added assurance that significant lateral movements were not occurring during construction.
Other recent instrumentation projects for which the principals of HGC have had a prominent role include: