Jeremiah Morrow Bridge Reconstruction, Warren County, Ohio
SEGMENTS, FALL 2013, VOL. 58
The new Jeremiah Morrow Bridge is a cast-in-place segmental concrete bridge on Interstate 71 north of Cincinnati (Figs. 7, 8 and 9). The new twin bridges will replace the existing truss structures, which were built in mid-1960s.
HNTB Corporation is the engineer-of-record for the project, and also providing on-going construction services to the Owner, ODOT.
The first of the two structures is being constructed between the existing bridges by Kokosing Construction Company, and scheduled to be open to traffic at the end of 2013. Upon completion of the first bridge the existing northbound structure will be demolished and the second bridge structure will be built in its place.
The new bridge is 2,252 feet long with 440 feet main spans. Each of the single cell boxes is carrying 55 feet wide roadway. The variable depth superstructure is 25 feet deep at piers and 12 feet deep at mid-span. The new bridges will be the tallest bridge in Ohio at 239 feet above ground when the $88 million project completed in May 2016.
The substructure of the new Jeremiah Morrow Bridge consists of cast-in-place twin wall piers resting on footings that are supported on either drilled shafts or driven steel piles. The abutments will be on small-diameter drilled shafts.
Typical span lengths are dictated by 16 feet segment lengths and balanced cantilever construction methods. The 40 feet long pier segment is constructed on falsework, accommodating two form travelers back to back. The thickness of web is 1'-6" at typical segment and bottom slab thickness varies from 9½" at mid-span to 3'-8 near the pier segment. The high-performance-concrete box girder is longitudinally and transversely post-tensioned to meet zero tension requirements at top slab for superior durability.
The 6-span bridge superstructure is integral with the twin wall piers except at Pier 5. Horizontal jacking will be employed to camber piers against the effects of creep, shrinkage and thermal effects so that the joint-free design can work for such a long bridge. The flexible twin wall piers are designed to dissipate creep and shrinkage effects, and thermal movements while providing adequate capacity for external loads. The absence of bearings and expansion joints except at abutments will reduce the long term maintenance costs significantly.
Segmental construction by balanced cantilever method is a good fit for this project given the structure’s height over the river and the steep embankments that compose the valley. Also, these techniques require minimal lifting operations by large cranes or heavy equipment positioned at the valley floor, thereby enhancing safety during construction and eliminating the need to restrict access to the Little Miami River’s scenic waterway, and the Recreational Trail for extended periods. This results in significant equipment savings and has the added benefit of minimizing impacts to the environment.