The USD 1.2 billion New Orleans bridge expansion project supporting roadway, rail, and marine traffic required Modjeski and Masters, Inc. to increase two nine-foot roadways in each direction, to three 11-foot lanes with eight-foot outside and two-foot inside shoulders, within the same right-of-way and utilizing existing river piers. To add the new roadways and design new approaches and interchanges at each end of the bridge, while still allowing three forms of transportation to use the bridge and traverse the project area, Modjeski and Masters needed flexible structural design and analysis software.
Modjeski and Masters used Bentley LEAP CONSPAN to design the bridge expansion to be constructed with minimal traffic disruption. The efficient design enabled construction engineers to preassemble the main bridge truss in 530-feet-long sections and erect the upstream and downstream portions simultaneously. The team designed Type III, IV, and BT pre-stressed girders for the new approaches and interchanges so they could fit around the existing ones, avoiding highway traffic interruption. Using Bentley software throughout the project facilitated the continual redesign of the superstructure as substructures were relocated.
Bentley LEAP CONSPAN saved immeasurable time and cost automating otherwise manual design processes and enabling quick and efficient design. The design concept and construction methods allowed three forms of transportation to continue to use the bridge and traverse the project area with minimal interruptions and delays, reducing the economic impact on the community. With a structural design that enabled the widened bridge to be constructed within the existing right-of-way, environmental impacts were minimized.
Bentley LEAP CONSPAN enabled Modjeski and Masters to quickly and efficiently design all the beams and girders for the new bridge approaches and interchanges, and was instrumental in designing the curved approach to the west bank where girder lengths varied by span and within a span. The flexibility of LEAP CONSPAN provided constructors with an adaptable design facilitating a pre-assembly, sectioned construction method for the main bridge truss, enabling constructors to erect both sides of the bridge simultaneously. Bentley software accommodated structural design changes throughout the project.