General Motors selected Ideal Contracting as the design-build contractor for the Estes-Cole Pedestrian Connector project at the Global Tech Center. The new pedestrian connector will allow for the movement of thousands of employees between the Estes and Cole buildings with the intent to inspire employees to work together and collaborate with efficiency.
As the design-build contractor, Ideal was responsible for coordination and collaboration between the Design Team which included SmithGroup, Ruby + Associates, and John E. Green.
Multiple design options were presented to the GM team. Immediately after contract award, the preconstruction team worked tirelessly to provide a design concept that was consistent with the design language on campus. The entire project team landed on a design that was not only consistent with the site’s overall design language but also consistent with the project’s budget constraints.
A Fast-Tracked Schedule
Not only was the project budget-constrained, it was also schedule constrained. Based on the needs of the Client, only seven months were available to complete the design, engineering, and construction of the new pedestrian connector. To satisfy the demands of the schedule, the preconstruction team was left with a maximum of 90 days to complete all required engineering and design. Within the first 30 days, steel needed to be released to meet the schedule. As such, the typical 30/60/90 review cycle was not the most effective way to execute the preconstruction activities. Our team collocated twice weekly for design and engineering and again twice weekly with the Client to approve our direction.
To further expedite the schedule, Ideal Contracting self-performed the earthwork, site utilities, foundations, flatwork, structural, and miscellaneous steel erection. Leveraging our self-perform expertise, we were able to analyze the original concept of deep foundations and evaluate the proposed loads to determine if we could use conventional shallow foundations for the structure. After additional geotechnical investigations and engineering, our team implemented a shallow foundation solution for the structure thereby improving the budget and schedule. Approximately 600 CY of earth was removed, and 400 CY of concrete was placed for the foundations of the pedestrian connector.
The structural steel was designed and fabricated within 30 days after the review and approval of the shop drawings. Due to the challenging site logistics with limited space between two occupied buildings and an existing retention pond, the Ideal team elected to assemble the connector structure into two large modules in an existing parking lot adjacent to the installation location. This allowed the team to maintain progress on underground utilities and foundations while the steel structure was being assembled into two box trusses, each approximately 200 feet in length with a combined weight of 140 tons. Once these sections were assembled and painted, they were prepared for erection.
The span of the pedestrian connector also proved challenging. The structure spanned four lanes of traffic and an existing stormwater retention pond. To allow for safe and efficient erection of the structure, the Ideal team decided to install temporary barges in the retention pond providing a safe work platform for the building envelope trades to work from. Once the barges were in place and secured, the two box trusses were transported to the erection location on wirelessly controlled Goldhofers and lifted into place using a 900-ton Liebherr crane in one shift on a Saturday. In one shift on Sunday, the structure was connected to the existing buildings to mitigate interference with site traffic on the roadway beneath the structure.
The team’s early engagement and highly collaborative approach to planning and executing the work ensured a safe delivery of the project with minimal impact on GM’s Global Tech Center campus.