SFPR – 64th Street/36th Ave Overpasses
Location: Delta, British Columbia, Canada
Client: Ausenco Sandwell/Ministry of Transportation and Infrastructure
The two overpass structures at 64th Street and 36th Ave. in Delta, BC, are part of the South Fraser Perimeter Road (SFRP) Project, Gateway Program. The proposed overpasses span the BC Rail Corporation line, which provides access to the port facility at Deltaport. The SFPR in these areas is a two-lane roadway constructed on mineral fill embankments with piled bridge structures. Under the footprint of the mineral fill embankments, ground improvement was used to improve the foundation strength and to mitigate the seismic hazards associated with the design earthquakes. MEG Consulting Limited (M+EG) was contracted by Ausenco Sandwell to perform the geotechnical design for the two overpasses.
M+EG’s scope of work includes the following:
- Site investigation (mud rotary drilling, SPT test and CPT test);
- Laboratory testing;
- Dynamic analyses and ground improvement design;
- Embankment design (surcharge requirement, stability assessment, review for MSE wall design);
- Pavement design;
- Pile foundation (axial and lateral analyses, pile drivability, set criteria);
- Site inspection and quality assurance for the ground improvement installation;
- Evaluate pile capacity using PDA results and CAPWAP analyses.
- Ground improvement by stone columns was proposed to improve the foundation strength of the cohesive layer, and to increase the resistance of the granular soils against liquefaction.
- Detailed analyses were performed to optimize the ground improvement layout and configuration, in order to achieve the most economical solution meeting the design criteria.
- PDA results were provided to M+EG for evaluating the axial capacity of the piles. The results of the PDA/CAPWAP testing demonstrated that the estimated axial capacities are consistent with the pile test results.