Understanding Causes of Concrete Culvert Pipe Joint Separation

Nearly 80% of culverts in Minnesota are concrete pipes. The most common distress affecting these culverts is joint separation between culvert segments. This may allow water and soil to seep through the pipe, which can lead to loss of soil support; this type of distress may ultimately result in roadway settlement and failure of the pipe. However, the cause of joint separation is unclear, so mitigation and construction practices that would minimize this problem have yet to be proposed. Thus, the purpose of this research is to determine the likely causes of joint separation in concrete culverts. The research will include a field survey of concrete pipes that exhibit joint separation, and correlations between joint separation and relevant site and structural conditions will be established. The field observation data will be supplemented by detailed geotechnical and live load test data from ten concrete culverts examined as part of an existing MnDOT implementation project related to live load distribution in reinforced concrete culverts. Computational models of the culverts will be developed to examine how the structure responds to traffic live loading, differential settlement, freeze-thaw of water in the joint, or swelling of freezing fine soils (e.g., silts and clays).