Large Diameter Pipe Piles in the Midwest: A Tale of Two River Valley Bridge Replacements-Video

Video Transcription

Video Summary

The speaker discusses MoDOT’s first two bridge projects using large-diameter steel pipe piles driven to rock. These piles offer higher capacity than conventional H-piles, can eliminate ground-line footings, and cause relatively little ground disturbance. Key concerns include pile damage, large-hammer availability, corrosion, and uncertainty in boulder layers and rock elevations.<br /><br />The first project, the replacement Champ Clark Bridge over the Mississippi River, used 48-inch piles for approach piers. All ten piles were dynamically tested. Testing confirmed the required capacity, although measured resistance rose sharply near refusal and sometimes exceeded expectations. Pile records suggested the piles had reached hard rock even though boring logs indicated otherwise, leading the speaker to conclude that the borings had misidentified the rock surface.<br /><br />The second project replaced a small bridge damaged by severe flooding and scour. With limited site access and schedule, 36-inch piles were selected instead of drilled shafts. Testing showed adequate capacity but higher-than-expected toe stresses, so driving criteria were adjusted to reduce damage risk. The bridge reopened in May 2020.<br /><br />The speaker recommends testing every pile, particularly when using this relatively new foundation type or non-redundant piles. Dynamic testing can improve confidence and may allow higher resistance factors to offset testing costs.

Keywords

large-diameter steel pipe piles

dynamic pile testing

bridge foundation

rock-socketed piles

pile capacity

scour damage

MoDOT bridge projects