Technology assists county in roadway planning
Steuben County, N.Y., is largely rural and latticed throughout with rivers and streams. Because of its rural nature, maintenance of the county’s infrastructure — including 678 miles of road and numerous bridges — most often falls on the county’s Department of Public Works (DPW).
In all, the county is responsible for more than 700 bridges, about half of which are less than 20 feet long. “We’ve got a lot of water up here,” notes Ken Longacre, a CAD specialist with the DPW.
Every year, the DPW inspects its bridges and selects a number to be surveyed and improved. The department uses a surveying gun, manufactured by Norcross, Ga.-based Leica Geosystems, which allows field personnel to label features onsite. County surveyors measure the GPS coordinates of riverbanks, as well as trees, buildings and any landmarks leading up to a bridge. They then download their raw data into surveying software, which creates a field book and captures the labels.
From the data, DPW engineers create maps using Land Desktop, and Survey and Civil Design software from San Rafael, Calif.-based Autodesk. They place terrain features in a “real-world” coordinate system, adding local watershed details if necessary. “We can look at vertical profiles and sections of the river, which we can check against previous maps to see if the banks are eroding and need reinforcement,” Longacre says.
If a bridge needs to be realigned or repaired, DPW engineers can plan the improvements using the software. If new concrete beams are necessary, they can design the beams and send the designs to a beam supplier, making the department one of the few in the state with in-house bridge design capabilities.
The DPW also undertakes regular road surface improvements that include flattening out stretches of hilly or bumpy road, extending sight lines and realigning dangerous curves. Surveyers take vertical measurements at intervals and view the road’s topography to create a digital terrain model. That model is used to compare current data with data from previous years to determine if deterioration has occurred.
In road and bridge improvements, the department also has the ability to do what Longacre calls “what-ifs.”“We can do three or four different scenarios for changing a curve,” he says. “To help us make the right decision, we’ll do several models of the same road realignment. After plotting and printing the different options, we show them to the department’s chief engineer. He can choose the best one.”
A central repository for drawings within the DPW allows different engineers and drafters to collaborate and build on the work of others. “We’re all networked, so one of us can call up the site plan from the database, rename it as a new file and use it for something we have to do,” Longacre says. “We don’t have to design things from scratch any more.”
In-house design also ensures that the department’s maps are more accessible. “[Not long ago], the head of our road construction crews wanted to see a cross-section, so he just walked over to the designer and she pulled it,” Longacre says. “If we had given the job to a consultant, we’d probably have had to mark up a drawing and send it out. The bottom line is, if we can do highway designs ourselves, we save the taxpayers money.”