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Rising to the Challenge: From Concept through Construction Repairs of the Existing Taylor Rd. (Callender Hamilton Through Truss Type) Bridge Grand Falls-Windsor, NL


The Callender Hamilton through truss bridge crosses the Exploits River in Grand Falls-Windsor, NL, and serves as a vital link for both industry and the public in the area. In January 2016, a heavy vehicle struck the bridge’s south portal strut and caused severe damage to several non-redundant truss top chord and diagonal members along with several other secondary members. Harbourside Engineering Consultants (HEC) were retained by Newfoundland and Labrador Department of Transportation and Works (NLDTW) to complete a repair design and procedure, with the mandate being to restore the existing structure’s full inherent capacity while minimizing design time, bridge closure time, and overall project costs. The project involved a number of challenges requiring an innovative and unique solution. Because the damaged elements included non-redundant members, the loads in these members had to be relieved by introducing an alternate load path prior to their replacement. Due to the site geometry, specifically a near-vertical cliff over 20m high directly in front of both abutments, along with cost and schedule restraints, standard repair methods were conceptualized but ultimately deemed impractical. The solution came in the form of an innovative temporary adjustable-length diagonal jacking strut design, whereby jacking struts were strategically located within the existing truss to create an alternate load path which bypassed the damaged members. A complex jacking system within the struts, including a creative sleeve-type slider system to maintain stability of the strut during the jacking procedure, was developed to maintain bridge geometry and relieve load in the existing damaged members prior to their replacement. A structural evaluation of the bridge superstructure was also part of HEC’s scope of work as the live load carrying capacity of the bridge was never verified since its construction in the 1960’s. The structural evaluation concluded that a number of structural elements did not meet Canadian Highway Bridge Design Code (CHBDC) CAN/CSA S6-14 requirements. As such, a combination of bolt material testing (to verify the existing bolt strength properties) and posting axle limits were recommended for the bridge following completion of the vehicle collision repairs. In addition to completing the detailed repair design and procedures, HEC provided an on-site Engineer for supervision and direction during all phases of the repair works, including the critical jacking sequences. The project was ultimately a success, being completed safely, on budget, and just marginally over schedule while meeting the main objective: reinstating the inherent load carrying capacity of the structure.

Conference Paper Details

Session title:
Pottie, W.