Overview and details of the sessions of this conference. Please select a date or location to show only sessions at that day or location. Please select a single session for detailed view (with abstracts and downloads if available).
Session Chair: David Hammond, City of Portland BES;
8:00am - 8:45am
Emergency! Completing Must Do Construction in a Short Work Window
Dave Christensen1, Daniel Reisinger2, David Scott3
1City of Renton, WA; 2Carollo; 3Tetra Tech; , ,
The City of Renton, WA owns and maintains a lakeline sewer buried within Lake Washington and serving the Kennydale neighborhood. A condition assessment of the lakeline found partial obstruction and the limited onshore access prevented effective cleaning. Without additional action there was potential for overflows into Lake Washington and backup into shoreline homes. The City issued an emergency declaration in June, 2018 reflecting the desire to complete cleaning by the end of summer.
The City has three existing submerged manholes allowing access to portions of the lakeline. analysis recommended additional manholes were needed to clean large portions of the line. To complete the manhole installation and cleaning the City obtained local, state, and federal permits. Permit conditions constrained the allowable work window to protect salmon. Further, this work window was within the prime swim/boating season valued by the Lakefront residents and park users at a popular City Park.
The implementation of the emergency declaration by the City assisted the work by:
Conveying the serious nature of the issue to Lakeline residents / customers.
Requesting expedited permit issuance - all agencies except the USACE were able to speed their processes.
Expediting City procurement with the selected Contractor able to provide design input.
The presentation will discuss the City’s approach to issuing an emergency declaration and the impacts on the project. The similarities with design/build type contracting mechanisms will also be reviewed.
While the construction and cleaning from temporary manholes in Lake Washington was successful, it was not without difficulty. The presentation will discuss challenges including:
Adapting when machinery can’t reach the site.
Identifying the effectiveness of cleaning through CCTV.
Addressing new permit conditions during construction.
Meeting hard deadlines for the end of work.
The presentation will be applicable for Operators, Engineers, and Utility Managers.
8:45am - 9:30am
When a Crisis Demands Bridging Gaps between Engineer, Owner, and Contractor
Murraysmith, United States of America;
After the wettest day on record at the Portland Airport, a 160 foot-long, 8 foot-wide, by 12 foot-tall arch culvert failed and washed out a portion of Kane Drive - a five-lane arterial and freight transit route in Gresham, Oregon. Following a quick assessment, engineers determined a temporary emergency repair was needed to get the road opened as soon as possible. This project serves as a great example of how to successfully respond to the type of emergency expected by a subduction zone earthquake or weather impacts due to climate change.
This presentation will share tips and tricks the City implemented to open after just 21 days, including: Removed restraints to teamwork by implementing a modified design/build approach; Authorized City PM, Engineering PM, and Contractor PM to make joint decisions; Rapidly evaluated options on the fly and supported quick decision making; Operated with a spirit of nimbleness and flexibility to maximum benefit; Aligned owner, engineer, and contractor goals by removing bureaucratic barriers; Committed to mutually beneficial continuous communication
This emergency project is a real-life example of how to prevail when faced with a natural disaster. The team’s commitment to flexible problem solving and sharing a common goal were keys to success.
9:30am - 10:15am
The Trenchless Two Step – Uniquely Combining Trenchless Solutions in the City of CDA
J-U-B Engineers, INC., United States of America;
Routine inspections, conducted by City of Coeur D’ Alene Wastewater Staff, uncovered an unmistakable non-routine problem that was in close proximity to the recently remodeled City Hall, Lake Coeur d’ Alene and the City’s iconic park. Limited CCTV images left more questions than answers, but revealed the top half of a 30-inch interceptor was entirely missing and an apparent void space remained above the pipe. At 32 feet deep, solutions were limited and full collapse of the pipe would have triggered a costly emergency response. Knowing the City’s interceptor was severely damaged and nearing catastrophic failure, J-U-B Engineers and City Staff worked closely together to quickly develop a project which provided a practical and economic solution that minimally impacted City patrons.
To identify a path forward, brute force nighttime investigations with a local contractor and City Staff provided valuable insight on the severity of the pipe and its unique underground conditions. Understanding the cause of the damage and investigation into the pipe’s distinct original construction method led to a clearer understanding of how a sinkhole was avoided for years, but highlighted several unconventional challenges for trenchless rehabilitation.
Multiple rehabilitation methods were considered including pipe bursting, slip lining, CIPP, fold-and-form, and spiral wound liners - each having their advantages and disadvantages. The overall construction cost and likelihood of success identified the less common water inversion CIPP installation method as the most practical solution, but added a high risk point repair and potential environmental impacts to the downstream collection system. Several void investigation tools, including seismic tomography and ground penetrating radar, were considered with this project. Ultimately, a customized trenchless point repair system was engineered to provide the pipe with structural integrity and bridge the collapsed pipe section prior to lining. Successful rehabilitation of the pipe was completed on time and on budget in the Spring of 2018.
City staff and J-U-B will present the decision path for this project, including lessons learned and how this project continues to unfold even after initial repair.