Burnside Bridge Test Program
Portland, Oregon is one of Americas great bridge cities. The Burnside Bridge is one of eleven signature structures that exist over a 16-mile stretch of the Willamette River. Located on one of the busiest streets in Portland, it is designated as an official emergency transportation route in case of earthquake or disaster. Gustav Lindenthal’s 1926 Burnside Bridge is a historically significant structure listed in the National Register of Historic Places. Although it has been seismically retrofitted multiple times in the last several decades it is no longer considered seismically resilient, therefore a new earthquake ready Burnside Bridge is underway.
The new foundation design will make use of large diameter drilled shafts that are well inclined to satisfy the major design criteria driven by high axial loads, liquefaction-induced settlement, and lateral spreading. Load resistance for the new drilled shafts will be met by extending them through liquifiable fine-grained alluvium, gravel alluvium, and deep into the lower Troutdale Formation
The load test program included installation and testing a full-sized dedicated drilled shaft with a diameter of 10 feet. Load testing such a large deep foundation element required double levels of bi-directional hydraulic cell assemblies with an astounding 102,000 kips of total jacking force. The load testing was complimented with multiple QA and QC test methods including SoniCaliper©, AFT-SID©, TIP©, and CSL.
