RECOMMENDATIONS

The project specifications should be modified to include the following:

• Three-dimensional tomographic images of the drilled shaft as a standard presentation to replace the current full waveform or XY plots of the CSL results.
• A document should be prepared and attached with the specifications that summarize CSL tomogram interpretation.
• UPV tests on concrete samples should be requested to be performed in conjunction with the concrete strength tests. Concrete samples should be of the same mix as that used for constructing the tested foundation.
• A customizes tomographic imaging software specifically for use with CSL should be developed.
• CSL systems with a single transmitter and multiple receivers should be used for collecting multiple offset data rapidly.
• The CSL tests should be conducted by FHWA or Department of transportation specialized teams and not by the contractor.

Currently 3-D tomographic imaging software can be purchased from companies such as GeoTomo, Texas, and Hampson-Russell software Services Ltd, Canada. Other engineering and environmental consulting companies provide services to the CSL users. For example NSA engineering, Inc., has an on line service where a program called CSLTOM03D may be accessed remotely through the internet network connection for data processing and output. Several other CSL service companies also have the capability to perform 2-D tomographic imaging.

The Government does not endorse any one CSL company, system, or tomographic imaging method.