District Surveys Upgrade to Future
March 29, 2013
- BIM Award
An innovative solution using computer modeling is helping to define and manage digital and geospatial data for ports, harbors and navigation channels in Alaska.
Developed by the U.S. Army Corps of Engineers-Alaska District, the new method is serving national initiatives to improve consistency.
Tom Sloan, chief of Geomatics Section, and Gene Hubbell, an engineering technician who works for him, combined their expertise to update the Alaska project condition survey templates using AutoCAD Civil 3D, a digital design software. Their product streamlines navigation project information between stakeholders while meeting national computer-aided design standards. Under the Rivers and Harbors Act, the district is required to dredge material to maintain varying sea depths and manage other project aspects.
"I think it adds efficiency when presenting our data to shipping companies and communities," Allen Churchill said, chief of the Operations Branch.
The National Channel Framework is one example of how the Corps is developing efficient ways to handle the details of the nation's navigational resources. While joined with the National Oceanic and Atmospheric Administration, it is a campaign aimed to provide each district an organized and authoritative inventory of their project sites while building geographic information system components into them. The framework's overarching goal is to effectively communicate with customers, the Corps and other federal agencies.
Overall, 53 different navigation sites in Alaska are monitored through the Operations and Maintenance program. Scopes of work and drawing sets are prepared for surveyors to conduct project condition surveys.
The documentation resulting from the contractors' efforts entails a combination of hydrographic and topographic analysis that allows staff to make informed maintenance decisions. It intends to show land and water surface features pertinent to navigation.
Sloan and Hubbell were eager to bring the surveys into the realm of Civil 3D imaging.
The team's motivation to update stemmed from the desire to ensure that accurate geospatial survey data controlled the modeling. Hubbell spent long hours developing a template for Craig Harbor in the computer program. He assigned it an Alaska coordinate system, and objects in the drawing are within centimeters of its true location on Earth, Sloan said.
After bringing the surveys into the template for Craig, they discovered that some of the old information recorded was incorrect. Deciphering these documents was confusing.
"We came to realize that a lot of the older CAD data was nothing more than annotated text," Hubbell said. "It wasn't really geospatially accurate."
In the past, it wasn't uncommon to have multiple authors, which resulted in an inconsistent archive.
Contractors hired by the Corps record hydrographic and topographic facts into the template created by the geomatics team. A site's hydrography is collected using an echo transducer. It determines elevations of the seafloor by measuring the speed of sound waves bouncing off the bottom and back up to the boat. The topography is gathered along breakwaters and the side slopes using GPS equipment.
The ingenuity of Hubbell and Sloan's method lies in the decrease for the chance of human error and increase in the accuracy of drawing datum. The template automatically populates point groups with relevant metadata as well. Before, this was manually typed into the computer by a CAD drafting technician. Sloan said contractors will have no problem completing the drawings because the software will do it for them.
"The key is the survey information is driving the modeling and sheet data rather than someone typing plain old annotation into a table," Hubbell said.
The new system should also help reduce cost by minimizing edits and drafting time.
The same symbols will be used for each survey using this new approach allowing for easier reference. A 3-D model can be rendered of the harbor and its depths. It will show high points on the basin exposing potential material needing to be dredged. It will also show low points along a potentially degrading breakwater.
"Now we've got a product meeting national standards and we're enforcing it through how Civil 3D works," Sloan said. "It's cool stuff."
The Alaska District won best project in the "Innovative Use of Civil 3D" category Jan.11 in the 2012 U.S. Army Corps of Engineers BIM Awards. Sloan credits the team approach and the robustness of the software in developing the method. The value of what it can accomplish excites him the most.
"We're seeing good results," he said. "It's going to make a better product for all of us, including our valued customers. This is something that should be shared at the next community of practice."
The award and new templates highlight the steps the district is taking to meet national goals pertaining to Alaska's ports, harbors and navigation channels' digital and geospatial details. Evidently, the new approach is already making waves.
Editor's Note: Mike Tencza, civil engineer in the Operations Branch, contributed to this article.