On behalf of the client, we coordinated geotechnical investigations to gather the information needed for the structural analysis, supplementing the tower records.  The investigations included borehole samples to determine soil properties and non-destructive testing to determine the size of the tower foundations below grade.  The results were summarized in written reports, identifying which towers were structurally adequate for the new loading and which required reinforcing.  The reports included graphical representations of the tower stresses, output from the software analysis, and tables summarizing the overall results for the various tower configurations.  Our detailed recommendations on reinforcement ranged from minor replacement of a few lattice tower members to complete tower replacement.

During the course of this project Morrison Hershfield reduced the overall engineering cost value by:

• Limiting the number of detailed analyses performed.  All structures were reviewed for similarities in construction, span length, line angles and conductor locations.  Loading trees were developed to group structures whenever possible, applying the results from one model to a number of different towers.
• Performing the structural design with a constant focus towards reducing the overall cost of construction.  Alternative installation strategies were evaluated, including various insulator configurations, conductor placement, structural reinforcement, additional mid-span lift structures and full tower replacement.

The client’s needs were further met by ahieving an aggressive design schedule.  All of the design work was completed within the targeted due date, eight weeks after receiving the client’s notification to proceed.