DJ&A was hired by Western Federal Lands Highway Division and the U.S. Forest Service (USFS) to design eight steel-girder bridges for a fast-track project. All survey, design, and contract preparation were completed within four months and all bridge construction within 12 months using innovative strategies and concepts from Accelerated Bridge Construction (ABC) to expedite design, material procurement, and final construction.
Due to remote access in steep terrain, along with timing constraints, the USFS required abutment designs without exploratory drilling. Innovative geotechnical design provided scour resistance and efficient construction utilizing precast abutment components and site-specific foundations. The foundations included deep micro-piles, micro-pile stabilized existing boulders, mechanically stabilized earth walls, and cast-in-place concrete on bedrock.
Roadside safety design criteria required Test Level (TL) I bridge rail for two bridges and TL II for six bridges. DJ&A utilized aesthetic crash-tested systems. Accurate, site-specific, bridge hydrology and hydraulics were critical as some of the bridges had previously washed out.
- Performed field review of all bridge sites
- Developed field report for constructability and environmental impacts of each bridge site
- Produced bridge vicinity maps
- Conducted topographic site survey and mapping
- Designed eight steel-girder bridges on an accelerated schedule
- Developed full construction package for bidding
This project was selected for presentation as an example of “Accelerated Design Using Prefabricated Components” at the 2014 Western Bridge Engineers’ Seminar.
Final costs were the same as those bid. Often contracts this complex in nature require cost adjustments but this one did not, which implies that the planning by DJ&A and coordination between FS and DJ&A going into the contract was at an efficient and very high level.
DJ&A managed the contract work in a professional manner that resulted in work efficiency beyond that of typical FS contracts that I have worked on. I believe their knowledge and experience working with our agency continues to result in exceptional results that exceed expectations.