In May 2021, the Concrete Bridge Engineering Institute (CBEI) salvaged key structural components from the decommissioned IH 35 NB to US 183 WB direct connector in Austin, Texas. This effort was part of an Interagency Contract (IAC) with the TxDOT Bridge Division, supporting ongoing research and education in segmental bridge construction and demolition. The connector was dismantled as part of a broader mobility improvement project that concluded in 2022.
This site is historically significant as one of the first segmental bridges in the United States to be fully decommissioned. An unpublished interim report was produced, and findings were shared at the 2022 ASBI Convention.
Superstructure Segment (Span-by- Span Construction)
This segment represents a typical precast segment from the ramp’s superstructure, constructed using the span-by-span method, where segments are placed sequentially and post-tensioned after each addition. The segment illustrates the modularity and efficiency of this method, widely used in modern bridge construction.
Notably, other parts of the ramp were constructed using the balanced cantilever method, which was the subject of extensive research by Dr. James Breen at the University of Texas. While this particular segment is not from a balanced cantilever span, it complements the broader study of segmental methods under varying structural demands.
Pier Capital and Anchorage Segment
The above image shows a precast, segmental pier capital — a rare element in bridge design where pier structures were assembled from modular segments rather than cast-in-place. This construction method allowed for reduced onsite labor and improved quality control.
The above image depicts an anchorage segment, a critical element used to anchor post-tensioning tendons that hold the segmental bridge together. This allows the structure to remain in compression and perform under heavy traffic loads.
Related Research: TxDOT Report 1404-3F (PDF)
Segmental Pier Columns
These column segments were salvaged from the IH 35/US 183 ramp piers and are made of precast, segmental concrete. Their modular nature helped speed up construction in the 1990s and reduced the need for complex formwork at elevated heights.
These columns are key examples of early experimentation with segmental design in support structures, not just in superstructures. Research from the mid-1990s by Dr. Breen’s team focused on the load performance and construction feasibility of such columns.