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route 72 manahawkin bay bridges project graphic


July 2014

(click on thumbnail photos to enlarge in bottom window)

This view shows the interior of a steel cofferdam for a water pier. Tremie seal concrete was placed within the cofferdam to keep the work zone dry and stable. Six steel pipe pile casings are the formwork for the reinforced concrete caissons and extend above the concrete seal. Crosshole sonic logging tubes extend out of the steel casings and verify the structural integrity of the concrete caissons at depths of more than 80 feet below ground. Sonic pulses are generated and received throughout the length of the caissons to provide the concrete caissons condition.
Workers erect the galvanized reinforcement steel cage before pouring concrete for the pier columns. The columns are founded on the pier's footing below which is inside the water-tight steel sheet pile cofferdam. The steel rebar cage conforms to the shape of the pier columns and adds strength and ductility to the column.
The construction of the pier cap reinforcement steel cage is on the right of the temporary construction bridge near the top of the photo. The pier cap is assembled on a barge independent from the primary construction structure so that large cranes can travel along the path. After each pier cap reinforcement steel cage is complete, a crane will place it on top of the pier column. After all the reinforcement steel is secured in place, forms will be installed to hold the shape of the columns and the concrete can then be poured.

This view is of a completed galvanized reinforcement steel cage for the pier cap which was assembled on a barge adjacent to the pier. Crews check for proper alignment of the reinforcement steel prior to lifting the cage into place. After the top of the pier column concrete is poured and gains the appropriate strength, the beams and bearings will be mounted on top of the pier cap.
This is a top-down view taken from the existing Route 72 bridge of the reinforcement steel cage for a pier column. The pier columns range from 26 to 72 feet measured from the top of the footing to the top of the pier cap. The reinforcement steel for each pier must be carefully detailed and fabricated to ensure the column is built to the appropriate dimensions.
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  Last Updated:  August 11, 2014