The Red Lillooet River Bridge is located east of Pemberton, on Hwy 99 (Sea-to-Sky) on a stretch of highway called the Pemberton Portage Road, which is a popular tourism route during summertime. The bridge crosses the Lillooet River and connects Pemberton to the Lil’wat Nation and Mount Currie. The 117-m-long two-lane bridge was built in 1987. Over the years, the bridge deck deteriorated and was rated as in poor condition. The deck top surface was extensively patched, significantly reducing rideability. The deteriorated state of the deck was highly visible, which attracted the public’s concern for safety. The objective of the Red Lillooet River Bridge Deck Renewal project was to resurface the deck and to improve the rideability and travelling experience.

The BC Ministry of Transportation & Infrastructure retained AtkinsRéalis to provide structural engineering services for the deck renewal. AtkinsRéalis conducted visual inspection on the concrete deck with the use of a snooper truck. The condition of the deck was found to be in poor condition and varied significantly along the deck, as such both partial depth repair and full depth repair schemes were developed for different areas.

The Red Lillooet River Bridge is an important part of Hwy 99 and an arterial gateway to the local communities; therefore, the design required construction take place in two phases and half width of the deck be replaced in each phase so that at least one traffic lane remained open with proper traffic management. Stringent specifications were developed for environmental protection such that no construction debris fell into the river. During the construction, to catch concrete waste from the deck removal, suspended scaffolding with enclosed containment was installed below the bridge superstructure.

The Red Lillooet River Bridge Deck Renewal project was successfully completed on August 30, 2023.

To determine a best-valued solution for the deck renewal, a detailed condition assessment was conducted to understand the existing state of the bridge. AtkinsRéalis’ structural engineering team reviewed past inspection and rehabilitation reports and conducted visual inspections of the bridge deck. All observations and findings were further studied and processed to identify areas and levels of deterioration. Given that the top surface showed extensive deterioration, two repairing schemes were developed based on the condition of the soffit. For deck area with evidence of bottom mat reinforcement corrosion, full depth replacement was recommended. For deck area with no deterioration visible in the soffit, partial depth repair was recommended. The majority of the deck overhang was in good condition; therefore, only localized partial depth repair was required.

The two deck renewal approaches of either partial depth or full depth repair allowed the bridge deck to be repaired meeting the project objectives. Partial depth repair was considered as long as the deck condition allowed, which reduced the construction cost comparing to full depth replacement. This cost effective solution minimized risks related to the environment, utilities, and public safety. Owner engagement was crucial in the design stage so that informed decisions could be made in a timely manner, avoiding repetition of work and rounds of communication.

The new deck consists of high-performance concrete and corrosion-prohibiting measures such as stainless steel reinforcement and galvanic anodes. The existing deck joints over the piers were replaced with new continuous reinforced link slab, improving rideability and user comfort. Link slabs also require less effort in future maintenance. During construction, to protect the river, suspended scaffolding with enclosed containment was installed. Construction completed with Highway 99 remaining open.