Project Description

A structural analysis will first be performed to determine the best course of action to address the sagging roof and cracked beams. Following the analysis and design, construction activities will occur. Construction can only be started once Reservoir 18 is complete and must be completed within one fiscal year as Reservoir 8-1 cannot be offline during the peak summer season. 

Why It's Needed

In fall of 2020, exposed rebar was noted in multiple areas of the roof of Reservoir 8-1. A structural condition assessment of the roof was immediately completed. The assessment determined that while roof failure is not thought to be imminent, the roof itself is nearing the end of its usable life as cracks were noted along the reinforcing grid spacing (i.e., structural rebar) on both the roof exterior as well as the roof interior. Cracks and efflorescence on the roof interior indicate that the intrusion of external water is occurring, which poses a potential contamination risk. Cracks were also noted along the interior roof beams, which may indicate potential overstresses in the beams. A waterproofing epoxy coating will be applied to the roof exterior in the near term to prevent further water seepage; however, further structural analysis and improvements must be considered to address the sagging of the roof and cracking in the beams.

Operations and Maintenance Impact

Slight impact during construction activities in fiscal year 2027 as the reservoir will be offline, but none once the reservoir is back in service.

Contact 

Anthony Steele, Senior Project Engineer: 971-514-9672 | anthony.steele@tigard-or.gov