BRIDGE REPAIR/REHABILITATION FEASIBILITY STUDY

6.0 SCOPE, COST AND SERVICE LIFE FOR REPAIR & REHABILITATION
The scope of work, estimated construction cost and anticipated service life for recommended
repairs and rehabilitation are summarized below.
Costs are reported in 2011 dollars (see Appendix G) and include mobilization, traffic control,
milling and resurfacing of the approach roadway pavement within the project limits, and a
contingency to cover miscellaneous items not considered and anticipated tolerances in unit costs
and quantities. The costs do not include engineering design, permitting and construction
inspection and engineering.
Because the factors that determine the rate of deterioration in timber members can vary
significantly, it is difficult to accurately estimate the service life of timber components. As such,
the anticipated service life associated with each scope of work is shown as a range that envelopes
the likely best case to the worst case scenario.
Recommended Repair Scope: As a minimum the existing bridge should be repaired to address
those elements that require immediate corrective action. The recommended scope of work for
these repairs include replacement of the wearing surface, structural deck, curbs, bracing and
fenders; replacement of the operating equipment (i.e. wire ropes, deflector sheaves, pulleys,
winches, and associated attachments); replacement of the electrical system; installation of FRP
jackets on the piles; repair of the abutment concrete; and reattachment of the guardrail. The
estimated cost of the repair work is $ 9,363,000 and is expected to provide a service life of 10 to
20 years before replacement of the bridge will be required.
Recommended Rehabilitation Scope: A Rehabilitation Scope with modifications that correct a
number of structural, functional, safety and reliability concerns would be a more cost effective
solution compared to the Repair Scope in that it will be less expensive and would provide a
longer service life. As such, a Rehabilitation Scope would be recommended over a Repair Scope.
The recommended scope of work for major rehabilitation includes complete replacement of the
timber structure (i.e. wearing surface, structural deck, railings, curbs, stringers and diaphragms,
lifting beam, sheave poles, cap beams, sills, piles, bracing and fenders); replacement of the
counterweight; replacement of the operating equipment (i.e. wire ropes, deflector sheaves,
pulleys, winches, and associated attachments); replacement of the electrical system; repair of the
abutment concrete; and reattachment of the guardrail. If desired, the timber railings could be
temporarily removed and reinstalled on the reconstructed bridge. Modifications and
improvements include replacement of the curbs with crash tested timber traffic railing including
timber guardrail along the approach roadways; minor widening of the sidewalks to address
accessibility including shifting the operating equipment and sheave poles, and widening the
sidewalks on the roadway approaches; installation of additional horizontal timber railing
elements or cable railing elements to the pedestrian railings to meet safety requirements;
replacement of the guardrail with pedestrian railing along the abutment wing walls; increasing
the capacity of the bascule span stringers and cap beams; increasing the capacity of the operating
equipment (i.e. wire rope, deflector sheave, pulley, winch, lifting beam and sheave pole sizes);
shortening of the counterweight arm to keep the counterweight from becoming submerged;
relocation of the pivot point and sheave poles and increasing the opening angle to improve the
Repair/Rehab. Feasibility Study March 10, 2011
Bridge No. C-07-001 (437) 53 Final Report