The interchange is being built under a US$558 million design-build-finance contract. Finley designed and provided the construction engineering on four high-level segmental bridge ramps that traverse the core of the interchange. The segmental bridge ramps were precast and erected as balanced cantilevers using a 140m launching gantry.
Photo by RobertHolmesPhoto.com
The bridge lengths varied from 335m to 747m in length and are 14.3m wide, with a maximum span length of 81m. The curved segmental bridge ramps are the third level of the interchange with radii down to 180m and have a maximum superstructure deck height of 29m above the ground. All of the bridges are supported on piled foundations and reinforced concrete piers and caps.
The high level segmental flyovers are built over multiple roads that carry 430,000 vehicles per day and are the tightest elevation curves erected in the United States. The all-overhead erection eliminated the need for falsework and cranes and reduced traffic impact.
The design will also reduce maintenance and construction costs through measures such as the use of external tendons. The use of polystyrene in the hollow pier columns, except at the base of the caps, eliminated the need for interior formwork and reduced the overall mass of the structure and concrete required.
