Alsea Bay Bridge

Alsea Bay Bridge

Newport, Oregon
United States
Alsea Bay Bridge

TYLin redesigned the Alsea Bay Bridge in Newport, Oregon to accommodate a unique cast-in-place segmental erection scheme.

When the construction contractor decided to implement a staged form traveler scheme used on a previous project in New Zealand, TYLin was contracted to redesign this 3,000-foot-long crossing of the Alsea River. The traveler scheme required a complete re-analysis and redesign of the post-tension system as well as detailing of the deck section.

To complete the redesign of this segmental box girder bridge, TYLin performed a comprehensive analysis. The staged concrete cross-section pours were evaluated within the cross-section for differential creep and shrinkage. We developed a time-dependent analysis of cross-section layers as a special application for this project. The collaborative redesign work on this structure was a precursor to the design-build project delivery method that is so common today.

We provided all superstructure redesign and developed all temporary foundations for construction engineering. Foundation engineering included full-scale pile load tests for temporary piles installed with a vibro hammer, without the need for later proofing with an impact hammer. The test was organized by TYLin engineers with the support of Dr. Tom Davisson (of the Davisson capacity criteria) and carried out onsite by the contractor.

Project Highlights:

  • Because of the pile load tests, the contractor was able to quickly install the temporary works piles across the entire channel without needing to divert the Delmag hammer used to install the permanent piles in the main foundations.  
  • TYLin served as the construction engineer for erection for the main span steel arch – a true arch requiring temporary support during erection. 
  • We supported the field operations with falsework and cofferdam designs and general engineering.