Nebraska Precast Record: 204th Street Bridge Spans Single-Point Interchange

Abstract

The 204th Street Bridge, with a single span of 63 m (207 ft), achieves a span-to-girder depth ratio of 31.5 using Nebraska University, 2000-mm-deep (79 in.), post-tensioned (NU2000 PT), spliced I-girders. It is the longest simple-span concrete I-girder bridge in Nebraska and perhaps the United States. Each girder line consists of three precast, pretensioned concrete segments, erected on false work and post-tensioned together after attaining the required strength at the wet joints and before forming the deck slab. High-performance concrete with a 28-day design compressive strength of 68.75 MPa (10 ksi) was used for the girders. A non-bulky NU post-tensioning anchorage block was used to house all the post-tensioning anchorage hardware. The bridge cost $624/m2 ($58/ft 2 ), which was less than the cost of typical precast, prestressed concrete I-girder bridges in Nebraska ($646/m2 to $807/m2 [$60/ft 2 to $70/ft 2 ]) at the time of bid letting. The efficient NU section and state-of-art design theory contributed to the success of this record-setting bridge. This paper presents the detailed description of the design and construction of the 204th Street Bridge in Douglas County, Neb.