Browsing by Author "Taylor, Craig"

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    Matrix (Partially Grouted) Riprap Lab Flume Study
    (Center for Transportation Studies University of Minnesota, 2014-04) Marr, Jeffrey; Weaver, Rita R.; Mohseni, Omid; Taylor, Craig; Hilsendager, Jon; Mielke, Sara
    The Minnesota Department of Transportation (MnDOT) in conjunction with the Saint Anthony Falls Laboratory (SAFL) has conducted a research study on the use of matrix riprap, or partially grouted riprap, as a spill-through abutment countermeasure. Spill-through abutments at river bridges require a countermeasure to protect the abutment from erosion and scour and often riprap is used. However obtaining large enough stone to protect the abutment can significantly increase construction costs. Matrix riprap, or partially grouted riprap, is an option that will allow for smaller stone, that when partially grouted, will provide equivalent protection to larger sized riprap. This study focused on matrix riprap applied to bridge abutments and included a review of published literature; site visits and observation of matrix riprap installation; laboratory experiments to evaluate matrix riprap application/installation (e.g., non-hydraulic experiments looking at rock and grout placement); experiments to test matrix riprap on a prototype abutment within a flume (hydraulic flume experiments), and finally hydraulic experiments focused on quantifying matrix riprap strength (steep flume experiments). Study results showed that the shear strength of matrix riprap was determined to be more than three times greater than conventional riprap in a laboratory setting. Additional investigation should be completed to better understand the application and performance of the matrix riprap, however this study can be used to support the use of matrix riprap in place of larger stone or other bridge countermeasures.
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    Thirsty Duck® Rating Curve Development
    (St. Anthony Falls Laboratory, 2012-02) Taylor, Craig
    The University of Minnesota, St. Anthony Falls Laboratory (SAFL) was contracted by Thirsty Duck, Ltd to conduct a testing program on a buoyant flow control device. The focus of the study was to develop rating curves and analyze debris performance for the ER-200 series device. Debris performance testing included leaves, grass (hay), aluminum cans, plastic bottles, and sticks/vines. The rating curves were monitored during debris performance tests to determine if the select debris impaired the function of the device. The ER-200 device was designed to be installed in a concrete inlet. For this study the device was designed for a Florida Department of Transportation (FDOT) Type C standard inlet (Appendix A). A diagram of the ER-200, provided by Thirsty Duck, Ltd, is provided in Figure 1. There are four primary components to the device. The first is a stationary sleeve which fits inside the concrete inlet. The second component is a moving flow restrictor that has both an orifice in the center and a flared base that creates the annulus between the flow restrictor and the stationary sleeve. Third is a set of floats that raises the moving flow restrictor such that the pressure head between the pond surface and the orifice and annulus is constant. Finally, a skimmer plate is attached to the floats to prevent floatable debris from entering the device.