Segment K is a portion of the 36-mile I-49 Corridor which constructs a four-lane interstate highway with a 4 ft inside shoulder and a 10 ft outside shoulder from the Arkansas state line to the Port of New Orleans. The entire I-49 Corridor will improve shippers’ ability to move goods quickly and safely nationwide and promote Louisiana’s economic growth by opening the state to new or expanded commercial opportunities. Segment K includes the design of the I-49/I-220 interchange and a partial cloverleaf interchange at MLK, Jr. Drive.
FINLEY’s efforts on this project include bridge design (EOR) for two of the three precast segmental bridges with span lengths from 120’ to 260’ and a radius 550’ (Ramp WN). These bridges consist of 700 segments, 271,000 sq. ft deck area, pier heights of 20’ to 90’ and three roadway cross sections 31.5’, 35.5’, and up to 52’ wide. The design includes external post-tensioning with Diabolos and a combination of haunched and constant depth segments which met the high aesthetic goals. External tendons will reduce future maintenance costs through improved future access for tendon replacement. The use of Diabolos eliminated traditional bent steel pipes, thus reducing segment weight and allowing for variable tendon geometry and continuous external tension ducts. These bridges were constructed by balanced cantilever crane erection. Portions of the bridge structures within the interchange were constructed over wetland areas and adjacent to an environmentally sensitive landfill which was aflame.
The flexibility of precast segmental construction allowed for a minimal footprint in these areas and off-site prefabrication of the superstructure. The temporary stability systems were designed to bear on the permanent footings and required no additional external supports. FINLEY also provided project management / administration coordination with the DOTD, roadway designer and sub-consultants; field visits and site inspection as directed by DOTD.
FINLEY’s post-design services included: shop drawing review; review of post-tensioning layouts, details, tendon elongations / stressing; review of calculations and drawings, temporary supports, erection and lifting equipment; review of calculations and manuals for geometry control; review of construction manual; design office support. These were the first precast segmental bridges built in Louisiana. This creates new opportunities for the DOTD in their options for long span, aesthetically pleasing structures and fast paced project delivery.