Malcolm Drilling Enhances Oregon’s Infrastructure with I-205 Abernethy Bridge Seismic Retrofit
The I-205 Improvements in Oregon include the seismic retrofit and widening of the Abernethy Bridge to withstand major earthquakes. Once complete, it will be the first earthquake-ready bridge to span the Willamette River in the Portland metropolitan area, establishing a regional north-south lifeline route after a disaster.
Malcolm Drilling was selected to install the deep foundations, taking on a critical role in the project. The majority of drilled shafts on this project were installed from an elevated work trestle or isolated platform over the Willamette River, designed for the most powerful Oscillator.
Two bi-directional load tests were performed on production shafts at the beginning of the project. Both test shafts (one 7 feet and the other 12 feet in diameter) were permanently cased to rock and had a total length of 250 feet.
The 28 production shafts varied in diameter between 6 and 12 feet and had depths of up to 250 feet.
All shafts were installed using the oscillator method and were either permanently or temporarily cased to the top of rock. The 5- to 20-foot deep rock sockets were installed in basalt with UCS of up to 25,000 psi. Each shaft required SID testing to verify and confirm competent material at the shaft bottom, as well as Thermal Integrity Profiling (TIP) and Cross-Hole Sonic Logging (CSL) to verify the integrity of the shaft concrete.
