Load Testing for Acceptance of Shafts with Questionable Integrity

PPT Presentation

Pdf Summary

The presentation examines whether load testing can help determine acceptance of drilled shafts with questionable integrity. Shaft acceptance should consider installation procedures and site conditions, construction observations and records, material testing, and integrity testing. Methods discussed include Thermal Integrity Profiling (TIP), Pile Integrity Testing (PIT), and High Strain Dynamic Testing (HSDT).<br /><br />Two Ohio bridge projects involved shafts installed at roughly the same time. In both, TIP indicated no temperature increase at the bottom of the tested shafts. Follow-up PIT identified possible anomalies, including a bulge in Case 1’s rock-socketed Shaft 8 and a possible anomaly at 21 feet in Shaft 1. PIT results also raised questions about rock-socketed shafts in Case 2. Installation issues had not been reported, though Case 2 had no cleanout details and its tremie was too short.<br /><br />Rather than core shafts or reject other shafts based solely on integrity results, the projects used high-strain dynamic load testing. In Case 1, the tested shafts had load-test lengths of 28.3 feet and 33.0 feet; rock-socketed shafts were accepted, with a maximum factored load of 254 kips per shaft. In Case 2, tested Shafts 19 and 20 supported acceptance of the shafts at a maximum factored load of 417 kips per shaft.<br /><br />The presentation asks whether load testing is a viable acceptance option, emphasizing that decisions depend on anomaly location, performance requirements, and durability. Its central conclusion is that drilled-shaft acceptance should be based on all available information, and that a shaft with an integrity indication may still perform satisfactorily.

Keywords

drilled shafts

load testing

acceptance criteria

integrity testing

Thermal Integrity Profiling

Pile Integrity Testing

High Strain Dynamic Testing

bridge projects

rock-socketed shafts

shaft anomalies