tilt-up re-entries 2010

Astoria 17th Street Dock Reconstruction

Astoria, OR

Technical Information Project Completion Date: July 2013

Project Location: Astoria, OR

Size of Project: 13,510

Concrete Strength Requirements: 4,000 psi

Water/Cement Ratios: .36

Unique or High Volume Mixtures: Water Reducer Type A, Superplasticizer Gleniium 3030

Unique Mix Designs: The ODOT spec required a NRMCA certified batch plant. There was no certified batch plant within 100 miles. The design team ended up approving an alternate mix design per ACI 318 section 5.3.2 requiring breaks of 5200 for 4000 psi mix.


Placement Challenges or Unique Techniques: The seismic design required moment connections at the top of the piles. Since the driven pile length was not predetermined, a prefabricated steel element was not practical. Concrete allows for the pile to be placed within tolerance in plan and then the top cut off. Concrete also allows for field variance in pile placement without the need for complex field welded connections.

Other Special Technical Aspects: Design considerations are given to berthing and mooring of vessels as well as consideration of wave and tide action. In-water and over-water construction are subject to many environmental regulations, most having to do with protection of ESA-listed fish species and marine mammals. A new concrete and steel dock (with the same deck footprint) that replaces an existing timber dock with creosote-treated piling is essentially self-mitigating in that the undesirable creosote pilings are removed and the number of new piling is less than 50% of the number of piling removed.

For this project, construction speed was very important due to the narrow in-water work window for fish, and the even narrower in-water work window for marine mammals.

Also, using precast concrete allows the deck to be placed quickly over water without the need for formwork other than the pile caps.



Located next to the busy Columbia River Maritime Museum, Astoria’s 17th Street Dock is a very popular and well used waterfront facility. The original 50-year old wooden dock was deteriorating, which was to costly for the City to maintain. In the summer of 2012 construction began on a new steel and concrete structure.


The City of Astoria wanted a low maintenance, durable structure that will stand up to the demands of Mother Nature and local marine traffic.


The dock currently services two Coast Guard vessels, various tour boats, the United States Lightship Columbia, and has accommodations for other vessels if needed.


Concrete was chosen early on as a durable product for this type of project. The design team chose cast-in-place concrete pile caps, precast concrete deck

panels, and a cast-in-place topping slab.


One key design feature on this project was a utility trench that kept all utilities below deck level. Construction of this trench required two levels of concrete pile

caps. The lower level was in the tidal zone and subject to wave action in the winter.


Over 500 CY of concrete was delivered to the jobsite during construction. The formwork for the lower utility trench needed to be prefabricated in large

sections and barged to the site.


While the site work was being completed, the precast supplier was busy offsite casting the deck and trench panels. There were (125) pieces of

precast used on the project.


Another challenge on the project was the rebar interface between the precast and cast-in-place concrete items. The precast deck panels had protruding rebar

that was welded for structural integrity.


Close coordination between the precast supplier and the contractor resulted in a successful fit once the pieces arrived on site.


The new Astoria 17th Street Dock is a showpiece for the concrete industry and the City of Astoria. The City now has a functional dock that will stand up to the harsh Oregon

Coast weather and will last for many years.

tilt-up re-entries 2010

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