Outdoor Laboratory and Testbed for Bridge Health

Background A 2017 study conducted by the American Society of Civil Engineers (ASCE), assigned nationwide bridges a disappointing grade of C+. This includes an estimated 9% of bridges considered structurally deficient, and nearly four out of ten bridges at or older than 50 years. This highly publicized study details the need for bridges to have significant maintenance, rehabilitation, retrofit, or replacement. In the absence of intervention and the fallout of our failing infrastructure, ASCE estimates $3.6 trillion to repair and replace this infrastructure. However, most bridge agencies, including NDOT, have limited resources to maintain and operate their inventory. Therefore, it is critical to understand how to effectively employ these resources and extend bridge service lives. Bridge health assessment invokes inspection, nondestructive evaluation, and destructive testing. Inspection and nondestructive evaluation are commonly implemented in practice; however, these techniques may involve subjective decision making, human interactions, and lack of verified or calibrated approaches. Furthermore, destructive tests such as deck coring and overstressing structural elements beyond their elastic limit are not commonly performed in practice due to their detrimental impacts to in-service structures. Therefore, realistic out-of-service bridge site(s) are critically needed to fully understand how bridges behave throughout their service life. At this time, a unique opportunity has arisen to establish an outdoor laboratory and testbed for bridge health. This involves using decommissioned and under-used steel and concrete bridge structures in Nebraska. The first outdoor laboratory bridge site is located on state route 92 over the Platte River just east of Yutan. Herein, this is known as the “Yutan (steel) bridge site”. At this site, two steel girder bridges cross the river in two separate crossings and were decommissioned in 2005 when replacement bridges were constructed to the north. These bridges have approximate lengths of 400 feet (east) and 1000 feet (west). As illustrated in Figure 2, these steel bridges exhibit various damage modes. This includes steel girder corrosion, abutment cracking, anticipated extensive concrete delamination, and reflective cracking in the asphalt overlay. The east bridge consists of (4) 100 feet spans comprised of approximately 54 inch welded plate girders with pin and hanger connections. The west bridge consists of eight 112 feet spans comprised of approximately 54 inch welded plate girders with pin and hanger connections. Both bridges at this site were designed in 1960. The second bridge site is located on state route 36 over the Glenn Cunningham Reservoir just north of Omaha. Herein this is known as the “Omaha (concrete) bridge site”. This concrete bridge was originally designed for a potential four-lane divided highway expansion in 1979, but has seen only minimal traffic loads. The concrete bridge at Omaha consists of three spans of 48, 60, 48 feet comprised of AASHTO girder type 3A. This bridge was designed in 1979 as a pair, where a second bridge to the south has supported all traffic of SR-0036 since construction. Various damage modes can be observed in this structure despite its minimal use, including localized scour at the abutment, abutment cracking, suspected delamination near the bridge deck weep holes, and cracking in the asphalt deck overlay. Many practical advantages exist for the use of decommissioned bridges as an outdoor laboratory in comparison to in-service structures. Some of these examples include: (1) No live traffic and consequently no need to for traffic control. Site access is reduced at both bridge sites and will be most restrictive at the Yutan bridge site. (2) No time constraints or scheduling is required for assessments. This is a result of no impact to traffic patterns or congestion. (3) Sites have increased safety since both have dead lanes. (4) Ability to create and share detailed information on these sites to develop “known and situated structures” at both bridge sites. Additionally, technology transfer can include a bridge inspection and nondestructive evaluation training site. This facility can be used by UNL, NDOT, consultants, and other external researchers due to its known and situated status. The bridges also provide full-scale trial structures to compare various nondestructive evaluation techniques for real, environmentally exposed, in-situ conditions. These bridges are also envisioned to support existing and future research projects as well as an outdoor classroom for various classes at UNL Civil Engineering. Objective The proposed research project has one overarching objective to transform two bridge sites (a total of three bridges) into a national research and educational facility for bridge health and testing. This will permit access for nondestructive evaluation and destructive test verifications. Furthermore, this facility can be leveraged for future research projects and identify strategic directions for this first-of-its-kind facility on realistic aging infrastructure.


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    • Status: Completed
    • Funding: $115074
    • Sponsor Organizations:

      Nebraska Department of Transportation

      1500 Nebraska 2
      Lincoln, NE  United States  68502
    • Project Managers:

      Halsey, Lieska

    • Performing Organizations:

      University of Nebraska, Lincoln

      1400 R Street
      Lincoln, NE  United States  68588
    • Principal Investigators:

      Wood, Richard

    • Start Date: 20190701
    • Expected Completion Date: 20211231
    • Actual Completion Date: 20220630
    • USDOT Program: Transportation, Planning, Research, and Development

    Subject/Index Terms

    Filing Info

    • Accession Number: 01705860
    • Record Type: Research project
    • Source Agency: Nebraska Department of Transportation
    • Files: RIP, STATEDOT
    • Created Date: May 24 2019 12:10PM