Big Silver River Multi-Span Bridge Design. Harrison Lake, British Columbia

The 155 foot multi-span bridge over the Big Silver River that flows into Harrison Lake is located approximately 40 kilometres north of Harrison Hotsprings, Bristish Columbia. Tamihi Logging Co. Ltd. wanted to re-use the existing set of steel bridge girders that was founded on aged and failing log crib abutments over salmon spawning habitat. 

Allnorth completed a site survey of the existing bridge, and subsequently designed a new structure utilising the old components.  The 135 foot girders were moved to a driven pile pier on one side of the river, and a new cedar log crib was constructed from locally sourced logs.  The span was retrofitted with Allnorth’s design for a jump span bearing seat.  The retrofitted structure comprised the original set of girders plus a second 20 foot steel span.  The girders were fitted with wood decking and guardrails. 

The success factors for this project included:

  • A design incorporating existing bridge components and generating significant savings during construction;
  • Removal of waterway constriction at the crossing, improving the stream cross section and reducing potential impacts to a salmon bearing stream.
  • Site survey of existing crossing and structure.
  • Detailed design - timber crib, driven pile abutment, jump span extension, and jump span bearing seat.
  • Construction assurance – site visits for construction review, and final construction documentation and crossing assurance statements.

Services in this project

Civil Engineering

Allnorth has the personnel and resources to effectively manage entire projects from concept to construction.

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Structural Engineering

Allnorth provides comprehensive structural engineering design services for industrial, commercial, and municipal clients. We design short- and long-span bridge structures; municipal, industrial, and commercial buildings; and temporary construction works.

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Our experienced team of professional and technical survey staff use Real Time Kinematic (RTK) GPS, robotic total stations, CADD On Site, and 3D laser scanning to support projects in a variety of industries.

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