HBK was responsible for the development of 6 miles of underground infrastructure designed for a 345kV XLPE electrical transmission line in downtown Chicago. The team’s responsibilities included the planning, implementation and oversight of all of the subsurface utility engineering (SUE) work. This installation encompassed engineered shored excavations of varying depth and types including deep trenches, manhole shafts, box tunnels, drilled soldier pile shafts and directional drilling methods. Additionally HBK was able to plan and design the temporary support & protection systems of existing utility infrastructure that could be affected during construction activities that would occur over the course of the installation. HBK’s team performed multiple site visits to assess existing infrastructure including adjacent building basements, vaulted sidewalks and potentially affected infrastructure as well as gained access to existing below grade utility structures to perform scans of the extents of the structures and the routing of existing infrastructure through them. HBK’s team compiled and correlated all the collected data to create a composite utility base map for further SUE exploration which included the layout and performance of vacuum truck test holing for obtaining level ‘A’ location accuracy of infrastructure at potential problem locations. The composite map was also used for determining the locations and layout for the performance of geotechnical & environmental soil boring investigations. In total, the project consisted of in excess of 200 test holes and 75 soil probes. Once all the field data collection, test holing and exploratory activities were completed HBK performed the infrastructure design for the installation which included manhole placement, duct bank plan alignment and profile design, cable pulling calculations and associated geotechnical and structural calculations required for the temporary and permanent aspects of the installation.
HBK was responsible for representing and supporting the project through the permitting process with the Chicago Department of Transportation (CDOT), the Illinois Department of Transportation (IDOT), the Illinois Commerce Commission (ICC) in addition to meeting with various city agencies and citizen groups.
HBK was able to provide on-site construction support with the participation of our staff as Construction Project Management, Resident Field Engineering, Construction Specialists, Record and Layout Survey Crews. HBK’s in office staff provided a responsive team that would support the field generated RFI’s resolution, coordination with ComEd’s internal staff and the overall design team.