Drilled Caissons for a Hospital Construction Project, Omaha, NE
Daniel Duffy (former student in geology and soils) worked on this project during the summer of 2003 and shared some pictures and geotechnical reports.  Daniel Duffy worked for Peter Kiewit Sons construction.

At the construction site, a vibratory pile-driver is used to loosen old I-beam piles that were in the ground from previous projects at the site.

A caisson auger is digging one of the holes for the caissons.  The wooden boxes surround the holes that have already been dug to keep people from falling into them.

Another view of the drill rig.

Here is some of the re-bar used to reinforce the poured caisson.

A picture showing one of the caissons.

Most of the caissons for this project were designed to support the load from skin friction.  This table comes from one of the geotechnical reports.  It indicates that loess was found to a depth of 40 ft and glacial till was found below this layer.

CPT tests results.  The second line graph shows sleeve friction, the 3rd line graph represents friction ratio, and the 4th line graph shows cone resistance.  (Click on the graph to enlarge.)

The last line graph is this picture shows angle of internal friction as a function of depth.  (I'm not sure what the first 3 line graphs represent.  Click to enlarge.)  

CPT results at deeper depths.

A spring-loaded, electronic device with wheels was used to examine the geometry of the caisson hole before concrete and rebar placing.  This picture shows the the variations in the diameter of the hole.  Any squiggly lines beyond the central cylinder suggests some of the wall has collapsed.

Side view of the data collected from the shaft wall measuring tool.  The shaft is 98 feet deep.  This view shows the location and extent of the wall failures in the shaft.

This graph shows the volume of the shaft as a function of depth.  This is useful when pouring concrete.