Sharp curves in the road on either side of Bridge 34 caused concerns about safety prompting this rural Indiana county to realign the approaches and replace the bridge. One of the challenges involved the bridge’s location in karst terrain, which consists of porous limestone that has dissolved over time producing empty pockets, fissures, and sinkholes.
As a result Lochmueller Group suggested using micropiles and the new bridge became one of the first examples to do so in Indiana. Micropiles are constructed by drilling holes into rock for the bridge piles, then backfilling the holes with cement grout and reinforcing steel, making for smaller, higher-strength supports, perfect for avoiding the many patches of open rock common in karst areas.
Replacement of the bridge included realignment of CR 375 West to remove a tight curve in the alignment and to provide a safer intersection at US 150/SR 56. The new prestressed concrete I-beam bridge consists of 3 spans (66.25’; 80’; 66.25) on a curved alignment, with spans built along the short chords. The bridge is supported on abutment walls on spread footings with multi-row micropiles and hammerhead piers on spread footings with multi-row of micropiles.