37,805 research outputs found

    Highway Administration Problems

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    Bridge pier scour under pressure flow conditions

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    The probability of pressurized flow conditions occurring in existing bridges is forecast to increase due to possible changes in extreme precipitation, storm surges and flooding predicted under climate change scenarios. The presence of a pressure flow is generally associated with scouring processes in proximity to the bridge. Scouring can also occur around bridge piers, possibly causing infrastructure failure. While there is a vast literature on bridge pier scour and pressure flow scour, only a few studies have investigated their combined effect. This study will provide a new overview of the main features of bridge pier scour under pressurized flow conditions, based on laboratory experiences. Special focus is placed on the analysis of the flow features under pressure and free surface conditions and to the temporal evolution of the scour. A comparison with existing literature data is also conducted. The results highlight the nonlinear nature of scour processes and the need to consider pressurized flow conditions during structural design, as the interaction between pressure flow and the bridge pier strongly influences scour features and leads to scour depths much greater than the sum of the individual scours created only by pressure flow or pier presence

    Fast Tracking as Standard Practice

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    In two short years, FHWA and MSHTO's Technology Implementation Group have sponsored 14 ACTT workshops, with more in the planning stage. Each attracts national transportation experts in specific skill sets who team up with colleagues from the host States to spotlight ways to shorten construction time, curb work zone congestion, and better serve motorists through improved quality. The workshops literally accelerate technology transfer by bringing innovative ideas to the table in concentrated two-day sessions. ACTT has cemented a track record of success in its workshops to date, according to participant feedback and results. Most agencies have found ways to slice construction time by 30 percent or more. Recurring recommendations have emerged: solutions with application to other highway projects across the States. The new approach to highway project development and construction is taking root as a standard practice. This second year report captures recommendations that have echoed through multiple workshops and distills the "best of" ACTT. It offers: recommended solutions by skill set and by project with a spotlight on those resonating through multiple State projects; benefits for participating State agencies; a look inside a workshop; the status of ACTT projects; phone numbers and e-mail addresses for experts; and an at-a-glance ACTT calendar of States and dates

    Modernizing Highway Administration and Organization

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    Highway Administration and Changing Times

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    Can You See Me Now?

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    For people to safely walk across the street, it must be easy for drivers to see them. Students will discover what makes it difficult for drivers to see people crossing the street and how to change the street to make it safer

    Research Guides Countermeasure Selection in Boulder

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    The City of Boulder merged research and user-friendly tools to create guidelines that provide recommendations for pedestrian countermeasures at controlled and uncontrolled crossing locations

    North Carolina Goes With the Flow(chart) to Identify Countermeasures

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    The North Carolina Department of Transportation (NCDOT) guidance uses roadway characteristics and pedestrian data to uniformly recommend pedestrian countermeasures at signalized and unsignalized crossing locations. NCDOT adopted the "North Carolina Pedestrian Crossing Guidance" in 2015 to guide crash countermeasures across the State's 14 divisions
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