• Chase Comeaux

Surveying the Sunshine Skyway Bridge


bridge
Sunshine Skyway Bridge, St. Petersburg, FL

Here at SurvTech, we consider ourselves innovative in the technology application department. We strive to be the best at using our cutting-edge technology to its full potential by looking for new approaches to solve old problems. Our Team often finds alternative ways to utilize this technology to deliver top-notch products more safely and efficiently. Not only do we want to know which is the right tool for the job but how many jobs we could do better with that tool.


underside of bridge
Underside of the Sunshine Skyway Bridge

For example, SurvTech was tasked with surveying the Sunshine Skyway bridge to determine clearances above MHHW (Mean Higher High Water) and MLLW (Mean Lower Low Water) across the main channel for shipping and other large vessels accessing Tampa Bay. There are a few ways we could have gone about it. One would have been to use a total reflectorless station. The cons to this would be that to collect the needed data points, we would have had to place personnel on the rock caps at the base of the bridge piers or possibly one of the surrounding dolphins. This method could have been costly or even deadly from a safety standpoint. A second con to this method is the reliability factor of the field personnel, both observing the suitable structures and documenting all the necessary information thoroughly. If something were to be missed, a return trip would only increase the initial safety risks. A third con would be that though the data collected might be sufficient, it would be extremely limited because only specific key points of the bridge structure would be surveyed.


Ariel view of bridge
Ariel view of the Sunshine Skyway Bridge

The second way to collect the information would have been to use a terrestrial lidar scanner. We would have certainly mitigated the minimal data con of an RTS but would still be limited in our scan perspectives and potentially be left with data gaps. The more critical safety factor is still present due to needing access to the pier bases. The span of the bridge would exceed or push some of these systems to their range maximums and gather returns at harsh angles, which would translate to a positional error in the data.


Keypoints of the underside of the bridge.
Keypoints of the underside of the Sunshine Skyway Bridge

The third method we chose was to deploy our Riegl VUX-1UAV mobile mapping setup on a 25ft Hydrographic survey vessel. The results were outstanding. While pulsing @550kHz and scanning up to 200 lines per second, we collected more data than was probably necessary, but we had a great context to evaluate the desired key points of the survey in- to the tune of +2,000 ppsm. We planned the survey path in a way that allowed us to capture complete coverage of the underside of the bridge while only utilizing shorter-range measurements across the span, which gave us greater immediate data accuracy. RTK( real-time kinematics ) checks were collected on features mounted to the four dolphins that were used to verify the global positional accuracy of the point cloud. This entire mission was executed from the survey vessel, which minimized the safety risk to our Crew, maximized the availability of data in post-processing to extract what was needed for the assessment, and provided great end results.


We don’t offer our clients the best solution for us, but we instead offer the solution that makes the most sense for our clients. SurvTech Solutions is committed to finding the best technology to g\iving our clients the most accurate data possible at a great value. Learn more about how to use our services and contact us today!



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