Port Mann/Highway 1
Location: Coquitlam, British Columbia, Canada
Client: H5M (Hatch Mott MacDonald/MMM Group)
• 2D non-linear dynamic analyses have been performed using the program FLAC, which can simulate a full range of static and dynamic conditions with coupled fluid flow and soil-structural interaction. Throughout the Central Segment (C2) of the PMH1 project, five (5) critical structures (including MSE walls, soil-anchor walls and bridge abutments) have been evaluated using FLAC to assess the seismic performances of the structures.
• Constitutive model - UBCSand model was used to simulate the dynamic pore pressure generation under earthquake loadings. The results of the liquefaction assessment from the 2D dynamic analyses have been compared with the 1D simplified analyses.
• The results of the FLAC analyses including the expected levels of ground deformation and the maximum forces generated in the reinforcement (metal strips or geogrid) system have been provided to the structural designer in order to compare/evaluate standard design approaches with more rigorous non-linear time-history numerical analyses.
• The 2D non-linear dynamic analyses can also assessed the 2D effects induced by the sloping till surface, which has not been considered in the code-based design approaches.
•Ground improvement by stone columns was proposed to increase the resistance of the granular foundation layers for earthquake design. Detailed ground improvement specifications were defined prior to installation of the stone columns. An initial verification trial was performed by the ground improvement contractor. Cone penetration testing was defined as the method for assessing the acceptability of the ground improvement work at the trial location in order to ensure that densification was achieved according to the specifications. The results from the trial area were used to verify the methodology of densification for the stone column installation.
• ICP piles have also been used to replace stone columns as ground improvement where there are space and/or utilities limitations for installing stone columns.
• Program Settle3D has been used to estimate the total and long-term settlements. To reduce the construction time, stages and surcharge durations, a detailed model with 3D contour settlement plots has been generated at the west abutment of the new Port Mann Bridge.