Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Evaluating Scour at Bridge Foundations on Rock: Status of NCHRP Project
The essence of National Cooperative Highway Research Program Project 24–29 is geotechnical site characterization in scour-relevant terms for use by hydraulic engineers. The goal of this on-going project is to develop guidelines for evaluating scour at bridge foundations on rock that can be integrated with the procedures of Federal Highway Administration Hydraulic Engineering Circular No. 18 (HEC-18). Rock scour in natural open channels appears to be related to five processes: 1) physical and chemical weathering that prepares rock surfaces for subsequent scour, 2) dissolution of soluble rocks, 3) cavitation 4) erosion and abrasion of degradable rocks, and 5) quarrying and plucking of jointed hard rocks. The definition of `rock' for scour purposes is just as problematic as the definition of rock for other engineering applications. The physical properties of rock material can range from strong soil to much stronger than the best concrete. Benchmark materials being considered for rock in the context of scour are concrete and mortar. Rock with characteristics less than that of mortar might be highly susceptible to scour when exposed to the normal range of stream flows during the life of a bridge. Quantifying the rate of rock scour is a challenge because it appears to be governed by a threshold hydraulic loading condition below which no scour occurs, but above which scour losses accumulate.
Evaluating Scour at Bridge Foundations on Rock: Status of NCHRP Project
The essence of National Cooperative Highway Research Program Project 24–29 is geotechnical site characterization in scour-relevant terms for use by hydraulic engineers. The goal of this on-going project is to develop guidelines for evaluating scour at bridge foundations on rock that can be integrated with the procedures of Federal Highway Administration Hydraulic Engineering Circular No. 18 (HEC-18). Rock scour in natural open channels appears to be related to five processes: 1) physical and chemical weathering that prepares rock surfaces for subsequent scour, 2) dissolution of soluble rocks, 3) cavitation 4) erosion and abrasion of degradable rocks, and 5) quarrying and plucking of jointed hard rocks. The definition of `rock' for scour purposes is just as problematic as the definition of rock for other engineering applications. The physical properties of rock material can range from strong soil to much stronger than the best concrete. Benchmark materials being considered for rock in the context of scour are concrete and mortar. Rock with characteristics less than that of mortar might be highly susceptible to scour when exposed to the normal range of stream flows during the life of a bridge. Quantifying the rate of rock scour is a challenge because it appears to be governed by a threshold hydraulic loading condition below which no scour occurs, but above which scour losses accumulate.
Evaluating Scour at Bridge Foundations on Rock: Status of NCHRP Project
Keaton, Jeffrey R. (Autor:in) / Mishra, Su K. (Autor:in) / Clopper, Paul E. (Autor:in)
International Foundation Congress and Equipment Expo 2009 ; 2009 ; Orlando, Florida, United States
10.03.2009
Aufsatz (Konferenz)
Elektronische Ressource
Englisch
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