Location: Delta, BC, Canada
The consultant was able to obtain high quality real-time data for the various parameters they monitored. Without the custom solutions RST provided, the data quality would not have been sufficient.
Potential safety concerns and costly disruptions related to the impact of the pile testing on the existing tunnel were minimized.
The Massey Tunnel in Delta, BC was built in the 1950s and is a congested tunnel structure. It averages 86,000 vehicle trips through it on a daily basis. A replacement bridge (Massey Bridge) was proposed to replace the tunnel and improve traﬃc congestion. The proposed capital cost of the project was $3.5 billion.
The replacement bridge design required a pile load test for a 2m diameter, 67m long, 60MN capacity steel pipe pile which required driving ﬁve 2m diameter pipe piles (1 test pile and 4 reaction piles) adjacent to the existing, operating Massey Tunnel. During the pile load test, the following parameters were monitored: loading from the hydraulic jacks, load transfer down the pile and displacement of the pile.
Due to the complex nature of the project, and the large capacity of the proposed bridge piles, traditional instrumentation was not suitable for the test. The driving of 5-2m pipe piles adjacent to the tunnel required crack and vibration monitoring of the existing tunnel structure. The project site is adjacent to the Fraser River where the ground consists of unconsolidated, ﬁne-grained, river sediments which are prone to settlement and liquefaction under seismic conditions.
RST worked in collaboration with Golder Associates to supply an elaborate instrumentation package, which included custom products, to precisely monitor the pile load test in the challenging environment.
The custom instrumentation allowed Golder to monitor the site parameters in real-time to allow for quick decisions to be made during the test, and for full analysis later on. Potential safety concerns and costly disruptions related to the impact of the pile testing on the existing tunnel were minimized.