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Client: USACE/Jacksonville District

Location: Puerto Rico

For over two decades, Arc Surveying & Mapping, Inc. has provided the Jacksonville District US Army Corps of Engineers with high accuracy surveys at dam sites within the district, including the Cerrillos and Portugues dams. Arc was included in the 2002 USACOE Structural Deformation Surveying Manual 1110-2-1009 (3-4) for a high resolution laser scan survey of the Portugues dam site prior to construction. The first 100% surface dam foundation survey of its kind.  Twenty years later during 2012, Arc resurveyed the Portugues dam construction site for the construction contractor, Dragados USA and the ACOE Resident Engineer to assure the roller concrete forms were properly placed.  After comparing Arc’s laser scan survey of the forms to the contactors survey and the contract drawings, Arc determined the construction forms were placed correctly. The placement of the forms at the precise location was important as this was the base of the dam from which all upward construction would be performed.  During laser scans of the project site, first order horizontal and vertical control monuments were a part of each scan.  In every case survey models, including control monuments, precisely overlaid precisely. 

After the construction forms were surveyed and determined to be in the proper location, Arc generated a model of the dam from contract plans. The cubic meter quantity of roller concrete material required was computed to three meter lifts and a color coded model provided.

As previously stated, Arc Surveying & Mapping provided Dam Structural Monitoring of both the Cerrillos and Portugues dams under continuing contracts for twenty years.

It is anticipated that the high definition accuracy of laser scanners currently in use by Arc will replace previous conventional methods of structural monitoring and we intend to compare the next dam scanning project to historic conventional data. Also to be considered is Arc’s ability to collect precise high definition multibeam swath data for incorporation into a complete 3D monitoring model.