(Norcross, GA, 14 June 2010) In a first of its kind effort, the Bureau of Reclamation’s Engineering Services Office in Boulder City, NV, built a detailed, highly accurate, as-built model of Hoover Dam’s 75-year-old Monument Plaza using high-definition surveying technology from Leica Geosystems.
Monument Plaza includes the Winged Figures of the Republic, two 30-foot high, statuary bronze sculptures that rest on a base of black diorite set atop a terrazzo floor. The floor is inlaid with a celestial map that pinpoints the precise astronomical time-September 30, 1935, 8:56 pm-when Franklin Delano Roosevelt dedicated the dam. Near the figures and elevated above the floor is a compass framed by the signs of the zodiac. There is also a nearby plaque commemorating the 96 men who died during construction of the dam.
The terrazzo floor is cracking and showing weather damage as are some of the bronze features on the Plaza, likely due to weather, pedestrian traffic and age. To determine repair or rehabilitation options, Reclamation needed as-built data of the Plaza to within a fraction of an inch.
Alejandro Orosco, LSI, surveyor with Reclamation’s Engineering Services Office, said, "We selected laser scanning because of the technology’s overall price, performance, and ability to integrate with our existing software and hardware inventory."
Orosco’s team gathered over two million data points over the course of four days. They used Leica Cyclone 3D point cloud processing software to manage most of the point cloud data and Leica CloudWorx to translate data into Autodesk Civil 3D application.
"The results are impressive. In a very short time, we created a baseline 3D model of Monument Plaza that is helping us evaluate structural changes in a clear, visual manner. The scanner’s capabilities have allowed us to cut down on field labor costs and capture a great deal of additional valuable data," says Orosco.
The results will ultimately help the agency determine the best method for restoring the plaza to its original condition. Using the free Leica TruView software, Reclamation and its partners are able to view, zoom in/out and rotate the model, measure distances, extract 3D coordinates, and create markups and hyperlinks.
Reclamation expects to contract an expert to review the facility history, scanner and survey data, and perhaps do some additional non-destructive geophysical exploration and core sampling in the next few months. With the consultant’s recommendations and assistance, they can develop a plan for returning Monument Plaza to its original condition.
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With close to 200 years of pioneering solutions to measure the world, Leica Geosystems products and services are trusted by professionals worldwide to help them capture, analyze, and present spatial information. Leica Geosystems is best known for its broad array of products that capture accurately, model quickly, analyze easily, and visualize and present spatial information. Those who use Leica Geosystems products every day trust them for their dependability, the value they deliver, and the superior customer support. Based in Heerbrugg, Switzerland, Leica Geosystems is a global company with tens of thousands of customers supported by more than 3,500 employees in 28 countries and hundreds of partners located in more than 120 countries around the world. Leica Geosystems is part of the Hexagon Group, Sweden.