Chelatchie Prairie Railroad Bridges Vancouver, Washington
The inspection and repair design for six timber trestle bridges along the Chelatchie Prairie Railroad utilized 3D modeling to improve infrastructure in this area of Southwest Washington. In leading the structural repair design, Otak performed field inspections of all six bridges including, surveying and documenting the condition of the structures and identifying deficiencies.
Scanning Technology Delivers As-Built Drawings to Retrofit Multiple Timber Trestle Bridges
Ranging in size from 50-feet to over 500-feet, the Chelatchie Prairie Railroad Bridges were originally built in the early 1900’s and had no previous drawings available. To support the production of as-built drawings needed for repairs, the survey crew used scanning technology to gather thousands of points on the structure. Data sets were then used to create a 3D model of the structure that could be used to generate the line work with as-built drawings. The density of the data allowed engineers to measure elements such as pile size without having to gather more data from the field. Utilizing this approach, the retrofit design for the bridges ultimately included replacement of stringers and braces, posting of decayed sections of timber piles, and rebuilding approaches and wingwalls. Special consideration was given in the design to minimize permitting requirements for the projects by ensuring all work stayed within the limits of maintenance and repair. By doing this, the permitting process was limited to documenting the work and concurrence with the permitting agencies so that no permitting review was required.
Because no previous documentation of the structures existed, the survey crew used scanning technology to produce as-built drawings for the Chelatchie Bridges. Data sets from thousands of points on the structure created a 3D model, allowing engineers to measure elements such as pile size without having to go back to the field.
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