Commotion Creek is located on Highway 97, approximately 20 km southwest of Chetwynd, BC. The Commotion Creek bridge consisted of a 3,150 mm diameter culvert and two smaller flanking culverts that were partially blocked with debris and therefore unable to convey flow since an extreme rain event in the spring of 2016. As a result of the blockage, flow was redirected and caused the highway and railway to washout approximately 1.3 km east of Commotion Creek.
The BC Ministry of Transportation and Infrastructure (MOTI) recommended replacing the existing culverts with a bridge and foundation piles.
Allnorth was appointed as Lead Designer, and using our team’s experience on large-scale and complex bridges, our team was able to evaluate several options for the crossing, including the costs associated with each option, as well as perform a cost benefit analysis on each alternative to determine the best design that met the project requirements. The cost benefit analysis factored in design, cost, and ongoing operation and maintenance of the proposed options.
The new Commotion Creek Bridge consists of a new two lane, single span 38.4 m long bridge with structural steel I-girders, steel pile foundations, cast-in-place concrete abutments, deck and parapets. A shallow depth superstructure was utilized to ensure that roadworks on the approaches were minimized.
Additional work included the reconstruction of 520 m of approaches.
Allnorth worked as part of a multi-disciplinary design team, whose scope included project management, highway design, hydrotechnical design, geotechnical design, archaeology, and environmental services.
The design development stage required coordination and management of the external design team (which included geotechnical, environmental, hydrotechnical, and MOTI team members), development of the design engineering requirements (loads, deck, girders, abutments and piles), and advancing the design drawings to 50% and 100% completion and IFC. Allnorth also provided standard specifications and tender documents to tender the project, and completed a pre-tender opinion of probable cost to ±10% accuracy.
The MOTI requested a superstructure design which did not include deck joints due to issues with maintenance. Allnorth achieved this requirement by incorporating a semi-integral abutment in the design, therefore eliminating all deck joints.
Allnorth was subsequently contracted to fulfill the role of Ministry Representative for the MOTI during construction, providing on-site quality assurance, survey layout QA and material testing QA. As Ministry Representative, Allnorth monitored the contractor to confirm construction progress for approval of payment to the contractor. Additionally the role included coordinating with all the Engineers of Record for each portion of the work, bridge structure, channel improvement and highway design.