Asset Inspection and Assessment

case study: brick sewer inspection and assessment

The City of Montréal retained Andrews.engineer to undertake inspection and assessment of portions of the major collectors in the downtown core. As part of this assignment, the firm inspected and assessed the condition of some 30 km of large brick sewers. These sewers included brick egg-shaped pipes, ranging in size from 1200 by 800 mm up to 1800 by 1200 mm as well as circular brick pipes up to 3150 mm in diameter (at depths of up to 25 m). Numerous other types and sizes of sewers were inspected, including a large horseshoe-shaped concrete pipe and basket-handle shaped concrete pipes.

Engineering services included sewer inspection, Sonar inspection, maintenance hole (MH) inspection, condition assessment, structural evaluation, and preparation of short and long-term rehabilitation recommendations. Inspections in the brick sewers were carried out using either conventional CCTV equipment mounted on a sewer crawler in the smaller sewers or combined CCTV and Sonar equipment deployed on a floating rig in the larger sewers

Detailed condition assessment was completed using the standard WRc approach with both structural and service grades assigned for each length of sewer. MHs were also assessed and a condition grade assigned for each. Specific findings were reviewed in the context of the City’s overall collector system needs; rehabilitation needs were identified and priorities assigned.