High Level Interceptor Structural Assessment

CITY OF TORONTO

Andrews Infrastructure was retained by the City of Toronto to inspect and assess the condition of a wide range of large diameter trunk sanitary sewers over a 5 year period. One of the trunks, the High Level Interceptor was constructed in 1910 and comprised a 2650 mm, circular concrete structure with a brick lined invert. Sonar and camera images showed that the system was in remarkably good condition. Isolated areas of possible deterioration were observed, however, which lead to focussed structural investigations.

A three phase program addressed a 2500 m segment of the trunk. Seventy concrete cores were extracted and tested, existing wall thicknesses confirmed, precise distortion measurements completed in key areas, and detailed structural analysis undertaken. Combined with a review of historical construction records, analysis showed that the sewer was in generally good, stable condition with the exception of several localized areas of deterioration.