This very unique project was brought to us by a Contractor client who had been tasked with performing environmental remediation and removal of two concrete hulled ships intentionally sunk by the Port in the late 1940’s. 

The two ships were World War II era concrete hulled Merchant Marine vessels constructed in 1944 and 1945 as part of specially designed fleet of 24 ships, the theory at the time being that steel was at such a premium during the war that concrete could be used instead.  After the war the War Department sold the remaining vessels to various buyers, one of which was the Port of Newport. 

The Port purchased the ships and sank them in Yaquina Bay to act as mooring bulkheads.  Better than 50 years later, new designs and ideas called for replacement berths and called for removal.  Peterson Structural Engineers was engaged to perform phased designs for systematic environmental cleanup of both vessels.  To do this, the individual holds and chambers of the vessels had to be fully drained and emptied of contaminated ballast.  However, the ships had to stay in their sunken position in order to maintain stability during cleanup operations. 

Peterson Structural Engineers was awarded a landmark project in Tacoma, Washington for the structural design of the two McMillin 33.0 Million Gallon prestressed concrete reservoirs.

The largest diameter water reservoirs constructed at the date of completion, they are each 485 feet in diameter. The base isolated tanks are prestressed with four layers of strand wrapping totaling over 300 miles. Each reservoir has a total of 332 columns. Combined, they have over 17 acres of floor and roof slabs.

PSE has completed structural design documents and construction services for this project, working closely with members of the project team to insure the right balance of economy and constructibility of design. Construction, filling and leak testing of both reservoirs was successfully completed in 2011.

PSE’s involvement in this project for the Oregon Department of Fish and Wildlife (ODFW) has extended for two decades.

It began in 1991 with the upgrading of a 30-year old fish ladder complex at Willamette Falls in West Linn, including the repair and upgrade of existing elements as well as the design of additional new structures. Following the floods of February 1996, the focus of the project expanded to inspect the damage to the fishway, study the potential for future flood damage and design for those anticipated conditions.

The investigation continued in 2009 when ODFW determined that additional damage had occured to the concrete structure and that an updated evaluation of the fishway was necessary. PSE entered into a competitive proposal process and was awarded the opportunity to lead the design team in the structural analysis and repair of the fishway.