The Effect Of Vibration On The Vero Man

Archeological Site

 In the Indian River County lawsuit against Peter Rigoff, Under Secretary of Transportation, reference to vibration is made on its impact to the Vero Man archeological site, as follows:

“Vibration associated with the Project is also a concern.  The focus of the excavation is eight to 12 feet below modern ground surface.  As a result the walls of the excavation are easily disturbed by vibration.  Additionally, the sediments at the site are dominated by sand which is far more easily disturbed by vibration than any other forms of sediments.”

We found this piece from the Transportation Research Board of the National Academies, entitled “Evaluating and Predicting the Effects of Vibration from Construction and use of Transportation Structures on Buried Archaeological Deposits.”

“When determining the potential effect a project may have on an archaeological site, indirect effects and well as direct impacts must be considered.  Encapsulating a site under fill material or capping it with concrete can provide some surface protection but there are many variables that may indirectly affect archaeological deposits from construction and the use of the finished transportation structure.

In evaluating effects, construction methods and equipment are key components.  Excavators, cranes, graders, etc. can weigh 80-100 metric tons.  Effects from vibration, compaction and destabilization of subsurface soils from excavation are possible.  Vibrations from pile driving construction shoring or bridge footings can exceed forces created by earthquakes, which may cause liquefaction.  Liquefaction occurs because of changes in pore pressure and reduced effective stress between solid particles generated by the presence of liquid.  It is often caused by severe shaking, and can cause sediments to mix; much like a liquid.

An alternative method to mitigate adverse effects from transportation projects..is the controlled burial of significant sites under highway fill or encapsulation under asphalt or cement.”