Segment K is a portion of the 36 mile I-49 Corridor which constructs a four-lane interstate highway with a 4-foot inside shoulder and a 10-foot outside shoulder from the Arkansas state line to the Port of New Orleans.
FINLEY provided bridge design (Engineer of Record) for 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 sf. 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, as well as upgrading and stressing of any single strand inside the box. Use of Diabolos eliminated traditional bent steel pipes, which reduced segment weight and this allowed for variable tendon geometry and continuous external tension ducts. These bridges are being constructed by balanced cantilever crane erection. This project had strong aesthetic requirements, environmental and site challenges.
Portions of the bridge structures within the interchange are being constructed over wetland areas and adjacent to an environmentally sensitive landfill which is on fire. The flexibility of precast segmental construction allowed for a minimal footprint in these areas and off-site prefabrication of 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 will include final bridge inspection. FINLEY’s post-design services include: shop drawing review; review of post-tensioning layouts, details, tendon elongations / stressing; review of calculations and drawings, temporary supports, erection equipment and lifting; review of calculations and manuals for geometry control; review of construction manual; design office support. These are 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.