ABSTRACT
The Hillsborough Bridge is Prince Edward Island Department of Transportation and Infrastructures (DTI’s) signature structure, which connects the capital city of Charlottetown with the bordering community of Stratford and southern portion of Kings County. It is the busiest section of highway in the province with a peak average annual daily traffic (AADT) of about 40,000 vehicles per day (vpd). Any service interruption at this location would necessitate a 57 km detour, causing significant user costs and delays. Originally a ferry crossing, it was replaced by a railway bridge in the early 1900, supported on 11 masonry piers with a turnstile (or swing) span to allow navigation of the Hillsborough River. This was replaced in 1962 with a truss structure, which carried two-lanes of automobile traffic. The deck truss still exists today.
Several modifications to the truss structure have since been completed including: widening of the structure to four lanes by used of a variable depth trapezoidal box structure, as well as strengthening some transverse members and truss joints to aide in the installation of municipal services and an Active Transportation Corridor.
Harbourside Engineering Consultants Ltd. (HEC), with the support of DTI, are conducting a Remaining Fatigue Life analysis of the deck-truss structure (the scope does not include the box girders). Due to the unique nature of the structural system in place, the analysis requires detailed modelling of the elements and connections, including the newer trapezoidal box details and connection to the deck truss.
This paper details the approach, including the use of a model calibrated using structural response data from controlled loadings, in determining the remaining fatigue life for the truss portion of the Hillsborough River Bridge per CSA S6:19 (Canadian Highway Bridge Design Code).
