LOUISVILLE, Ky. – Another milestone has been reached in construction of the new Downtown Crossing, with work progressing above the surface of the Ohio River.
Walsh Construction crews have set a tub that will be used to construct the west portion of the waterline footing of Tower 5, the pier closest to the Indiana shoreline.
The yellow tub is the form that will retain the wet concrete that is poured to form a portion of the waterline footing. The tub is a large box, weighing over 240,000 pounds that has a precast concrete floor and steel plate girder walls. The tub, which is 61 feet long and 22 feet wide, has been lifted and set over two drilled shaft casings.
The setting of the tub marks the first visible sign that construction of the new pier is progressing above the surface of the water.
Prior to this week, the work has focused on the installation of the 12-foot diameter drilled shafts, the bridge foundations that extend below the water, below the riverbed and into the bedrock.
Tie down rods embedded into the concrete keep the tub in place. The void between the tub floor and shaft casings will be filled with grout and the tub will be dewatered. A reinforced concrete bottom seal that is two-feet thick will be poured into the bottom of the tub, providing the support for the weight of the massive waterline footing.
Reinforcing steel is installed and the concrete is poured for the waterline footing. This is a mass concrete pour that will require the installation of a cooling system. The procedure will be repeated for the east portion of the waterline footing for Tower 5.
The concrete pour for the west portion of the waterline footing for Tower 5 is expected to happen in late October and the east portion in November. The pouring of the lower cross beam and the leg pedestals is expected this winter. The first Tower 5 leg sections are expected to be poured in spring 2014. The construction of Tower 4 will then begin.
The bridge will be built with nine piers, four on land and five in the water. Three piers will include tower supports, comprised of the four drilled shafts, a waterline footing and two tower legs.