City of Fort Worth retained Hayden to provide field verification of the installation of 1700+ LF of new 36” sewer pipeline and tunnel. The new pipeline was 36” fiberglass pipe installed in 50” inside diameter lag and beam tunnel. The tunnel depths were between 19-36 feet deep. Hayden’s team produced a project-specific health and safety plan that included the requirements for confined space certification, personal protection equipment, ventilation and lighting and other safety measures required for all parties involved.
Hayden was requested to verify the grade and alignment of the newly constructed tunnel and provide data points in comparison to the design plans. The field crew used a Leica Multistation 50 to scan up to 150 feet into the tunnel from open access shafts. For shots beyond the scanning area, the field crews entered the tunnel to record ground shots and tunnel measurements every 50 feet. The field horizontal alignment and vertical profile was overlaid on the original sewer line plan-profile design. The data points were also graphically represented in cross sections from the scans providing verification the shape of the constructed tunnel.