Wood Research and Development (WRD) was commissioned by NBDTI to inspect and evaluate a covered bridge within the Saint John region. The covered bridge consisted of two Howe truss spans, each with a span of ~33 meters and nearly 100 years old. WRD conducted the inspection using Non-Destructive Testing and used this information to derive the residual capacity of the elements as well as provide a load rating of the structure.
The structure is highly unique as additional considerations such as snow load and overturning were required. The inspection report provided outlined varying levels of restorations, depending on the desired load rating of the structure. WRD completed the restoration design to upgrade the posted limit from 5 tonnes to 30 tonnes utilizing advanced timber repair methods, which encompassed high strength fibre, timber laminates and a new floor system. In addition, WRD designed a lifting apparatus to raise the structure off of the hog jaw system for safe removal as well as reinstate camber. The design development throughout the project was dynamic in nature as the restoration progressed, finding latent conditions, and designing the repairs as construction continued.
The heritage of the structure has been persevered and maintained and by using advanced timber repair methods, which can now sustain over double the load as originally designed for 100 years ago. With proper maintenance and care, this structure can continue to operate for another 50 years or more.