by Ted Mort
Earlier this year our team was approached with an opportunity to work with an Arizona contractor who was pursuing a bridge renovation project. We reviewed the available information and selected our equipment. We use a variety of scanners from several manufacturers and this gives us the ability to execute each project with the proper tool or tools. In this instance we decided to go with the Leica C10 for its range and traversing function. So far this was not an atypical project, but once on site the challenges began to emerge.
This bridge was in one of the far corners of Arizona and not only was its location remote, but it was entrenched deep in a canyon. Include in the scenario a winding river that had a habit of picking up speed and a 16” shoulder on the bridge itself and we’ve got a recipe for high risk. Although picturesque, this was not the cake walk we anticipated.
We do quite a bit of due diligence when orchestrating a project and refer to a variety of resources for our planning. Even with our proven procedure, we couldn’t ascertain the intensity of these conditions through the typical research methods. This is where our acquisition teams experience and unparalleled communication come into play.
Once the team arrived on site they took stock of the situation and contacted support at the office. It was apparent that we weren’t going to be able to traverse across the bridge due to the volume of traffic and limited operating space in the shoulder. They took photos and uploaded them to the cloud for review and strategic planning. The photos immediately caught the attention of the project captain as he noticed that the divider in the highway also contained a seven foot fence. This fence would prevent the team from relaying control to the opposite side of the highway.
We decided not to waste time and began low risk elements like locating aerial panels and tying in points for future scan positions at both ends of the bridge. Another part of our scope was to capture approximately half of a mile leading into and out of the bridge, this would also buy some time for brainstorming while allowing our acquisition team to keep moving forward.
Back at the office we began to formulate a plan to provide a high density point cloud along the bridge surface without actually getting out on the bridge. We knew that even if we increased the scanner height and resolution the result would be accurate but not thick enough to provide a compelling visual once loaded into AutoCAD and Navisworks (the preferred software of our client). Our in-house Cyclone expert suggested that we mesh the surface with the accurate but sparse return data and redensify it based on the mesh. This would increase the point count to an intuitive level once in the target software package. I was sold, and figuring that the largest challenges had been overcome I returned to my office… only to pick the phone up again in a few minutes.
Jim was gone. “Who’s Jim” you might ask. Jim is in charge of the acquisition team and had just come up missing, along with the C10! As I calmed down the folks on the other end of the phone (who feared the worst in this harsh environment) I start to get the story. The crew dropped Jim and the equipment on one end of the bridge to start scanning and they began the long 10 mile trip to the nearest turnaround. They would double back and set up the back site on the other side of the highway. Upon return they got unpacked and turned around to find a barren drop off point that should have been the place Jim was set up. Through 20 minutes of recounting their steps and speculation into countless ways that Jim had disappeared (including what I can only assume to be some twisted reference to “The Hills Have Eyes”) Jim reappeared next to them! You see, Jim is an avid fisherman and while waiting he uncovered what appeared to be an old fishing trail that crept along the cliff under the bridge. Not only did it lead to “a sweet trout fishing spot” but it would also allow us to traverse right across without endangering anyone.
All said and done, it was an excellent example of how communicating site conditions and outside the box thinking can turn a hairball of a project into “the easiest laser scanning experience” our client has ever had.