Waco Suspension Bridge Aerial Design Survey

Waco, TX
October 2020
Aerial , Public Works , Surveying ,

The Waco Suspension Bridge is a historical landmark located in downtown Waco, Texas that was built in 1870 by Thomas Griffith, a New York civil engineer. He commissioned the bridgework and cables for the project to be supplied by The Roebling Company, the same firm that later helped build the famous Brooklyn Bridge. After completion, The Waco Suspension Bridge quickly provided a crossing over the Brazos River for the Chisholm Trail and other north-south travel through Texas. Due to high traffic, the town doubled in size over the next decade which contributed greatly to The City of Waco’s development. Recently, 1519 Surveying, LLC (1519) was engaged by the Engineering firm hired by the City of Waco to refurbish this 150-year-old bridge to its past glory.

1519 had to produce an Engineering Design Survey on this piece of Waco history, which required the integration of UAV Mapping/Photogrammetry and field surveying to produce point cloud files and orthoimagery within the project limits. The point cloud and orthophotos were used to provide accurate measurements of specific bridge features such as hanger and floor beam lengths for refurbishment purposes. Data was acquired using drone photogrammetry with over 1000 photos taken from various angles and flight paths over and around the bridge. Photogrammetry software was then used to generate the 360-degree point cloud and orthophotos. Drone data was then merged with field surveying shots and terrestrial scanning point cloud files in a CAD environment to deliver the requested measurements and values from the client.

Deliverables included a digital design survey drawing in AutoCAD (.dwg) showing visible surface features and requested measurements located, an ASCII point file, a copy of field notes and field sketches, point cloud files in LAS format, and digital aerial orthophotography of the entire bridge structure.