Investigation, Design, and Construction of Rock-Socketed Drilled Shafts-PPT Presentation

PPT Presentation

Pdf Summary

The presentation describes the design, construction, and inspection of rock-socketed drilled shafts for three-span bridges at Toro Creek and Old Creek. Both projects used permanent-cased shafts socketed into sedimentary rock, with shaft and socket dimensions varying by bridge location. Subsurface investigations found alluvium over rock: approximately 47–55 feet of medium-dense to dense alluvium at Toro Creek, compared with 18–35 feet of very loose to medium-dense alluvium at Old Creek.<br /><br />Construction topics included water management, permanent casing installation, shaft-base cleanout using air-lift systems or flat-bottomed buckets, and slurry sampling and testing. Base cleanliness requirements and shaft inspection methods were also discussed.<br /><br />Quality-control testing identified anomalies at both sites. Toro Creek gamma-gamma logging indicated potential defects in several shafts, including some that could affect up to the full cross-section. At Old Creek, gamma-gamma and cross-hole sonic logging found anomalies in a pier shaft. The presentation addresses defect mitigation, construction challenges, and the value of contractor collaboration and adapting methods to site conditions.<br /><br />The presenter notes that the views and recommendations are their own and are not necessarily endorsed by DFI.

Keywords

rock-socketed drilled shafts

bridge construction

Toro Creek

Old Creek

permanent casing

sedimentary rock

subsurface investigation

shaft inspection

quality control testing

gamma-gamma logging