When Hurricane Maria struck in 2017 it delivered a devastating blow to the island’s energy infrastructure. Before critical fuel storage tanks could be reactivated to supply essential needs, the massive structures needed to be inspected to assess any damage caused by Maria. Restoring the flow of gasoline, diesel and other fuels to Puerto Rican residents and businesses hinged on getting the terminals and tank farms at Yabucoa back into operation. The inspections needed to be completed quickly and accurately.
In order to quickly provide the required information, MForce Surveying, a leading surveying firm used a Trimble SX10 scanning total station to capture comprehensive data on tank interior and exteriors. “3D scanning is very valuable on sites like these,” said MForce president Carlos Fournier. “We can collect comprehensive data on complex structures. The fieldwork moves efficiently, and the comprehensive data eliminates the need to revisit the site.”
For each tank, MForce crews determined optimal locations for the SX10, selecting four or five intervisible setup points that provided a complete view of the tank. At every point they established georeferenced coordinates by using a Trimble R8 GNSS receiver in conjunction with Puerto Rico’s VRS network. Then the crews set up the SX10 and used the surveying workflows in Trimble Access™ software to capture high-accuracy point clouds of the tank exterior. In some cases, they could also use the SX10 to scan tank interiors.
Field data was downloaded from Trimble Access into Trimble Business Center Software (TBC). “With TBC we combine the GNSS positions with the total station and scanner measurements,” Fournier said. “Because the SX10 data was already georeferenced, we did not need to register or combine the scans, which saved a significant amount of time and effort.” Technicians then used Trimble RealWorks® software to examine the tanks. The RealWorks Tank module can model a tank and develop heat maps and other analyses that reveal issues in roundness and verticality of the tank shell. MForce technicians used RealWorks to produce deliverables based on American Petroleum Institute (API) Standard 653 specifications for tank inspection. Information from the Trimble system was also shared with Autodesk Revit software for additional modeling and engineering analysis.
The speed and accuracy of the SX10 scanning was essential for the work. “You must have complete confidence in your measurements,” Fournier explained. “Some of the deformations occurred high up on the tank walls and could not have been detected without the accurate scanning.” The MForce analysis could reveal deflections as small as one inch in a tank 200 feet in diameter. The results from the Trimble system enabled tank operators to ensure safety and integrity in their work to recover from the crippling storm.
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