Dynamic ice forces on piers and piles. An assessment of design guidelines in the light of recent research

Neill, Charles R.

doi:10.1139/l76-030

Cited by 50 publications

(14 citation statements)

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“…This was achieved by scaling the natural frequencies and ensuring that the lowest natural modes were easily excited at the ice-action point. The first natural frequency of bottom-founded structures in the Baltic Sea and Cook Inlet is typically in the range 0.3-4.6 Hz (Blenkarn, 1970;Määttänen, 2008;Neill, 1976). Additional details about the dynamic scaling for this particular test setup can be found in Määttänen et al (2012).…”

Section: Test Structurementioning

confidence: 99%

Laboratory experiments to study ice-induced vibrations of scaled model structures during their interaction with level ice at different ice velocities

Nord

Lourens

Määttänen

et al. 2015

Cold Regions Science and Technology

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Section: Test Structurementioning

confidence: 99%

Laboratory experiments to study ice-induced vibrations of scaled model structures during their interaction with level ice at different ice velocities

Nord

Lourens

Määttänen

et al. 2015

Cold Regions Science and Technology

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“…Several observations of ice-structure interaction conducted on other piers seem to confirm Peyton's conclusion though. This topic is perhaps best summed up by the work of Neill in 1976: "The force oscillations remain a controversial topic, but a simple explanation appears tenable: that ice tends to break into fragments of a certain size distribution and that this size distribution together with velocity determines a frequency spectrum. As the sheet slows down, the frequency, as expressed by velocity divided by size, should drop proportionately, which accords reasonably well with Peyton's records" (Neill 1976, p. 319).…”

Section: Subsequent Studies Of Ice-structure Interaction Process By Bmentioning

confidence: 99%

Modal Analysis of the Ice-Structure Interaction Problem

Venturella

Patil

McCue

2008

Volume 3: Pipeline and Riser Technology; Ocean Space Utilization

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In the present study, the author builds upon the single degree of freedom ice-structure interaction model initially proposed by Matlock, et al. (1969Matlock, et al. ( , 1971. The model created by Matlock, et al. (1969Matlock, et al. ( , 1971, assumed that the primary response of the structure would be in its fundamental mode of vibration. In order to glean a greater physical understanding of ice-structure interaction phenomena, it was critical that this study set out to develop a multi-mode forced response for the pier when a moving ice floe makes contact at a specific vertical pier location. Modal analysis is used in which the response of each mode is superposed to find the full modal response of the entire length of a pier subject to incremental ice loading. This incremental ice loading includes ice fracture points as well as loss of contact between ice and structure. In this model, the physical system is a bottom supported pier modeled as a cantilever beam. The frequencies at which vibration naturally occurs, and the mode shapes which the vibrating pier assumes, are properties which can be determined analytically and thus a more precise picture of pier vibration under ice loading is presented. Realistic conditions such as ice accumulation on the pier modeled as a point mass and uncertainties in the ice characteristics are introduced in order to provide a stochastic response. The impact of number of modes in modeling is studied as well as dynamics due to fluctuations of ice impact height as a result of typical tidal fluctuations. A Poincaré based analysis following on the research of Karr, et al. (1992) is employed to identify any periodic behavior of the system response. Recurrence plotting is also utilized to further define any existing structure of the ice-structure interaction time series for low and high speed floes. The intention of this work is to provide a foundation for future research coupling multiple piers and connecting structure for a comprehensive ice-wind-structural dynamics model.iii DedicationTo my wife, Jeanine Anne Venturella, who• put up with me throughout the process of this research • reviewed and edited the written portion • listened when I needed her to iv

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“…Neill (1976) reviewed available field data and the results of small-scale laboratory tests and assessed various analytical approaches and design formulae used to estimate the impact of moving ice on piles and piers. Guidelines for determining ice forces and other ice effects on bridges can also be found in Gerard (1983), Neill (1981, and CSA (2000).…”

Section: Forces Applied On Piers By Floating Ice Sheetsmentioning

confidence: 99%

Hydraulic effects of ice breakup on bridges

Beltaos¹,

Miller²,

Burrell³

et al. 2007

Can. J. Civ. Eng.

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The passage of river ice during the breakup event can have several effects on bridge structures. Design for ice passage at bridges has largely been empirical, such as the determination of superstructure clearance requirements based on historical stage data. As hydrologic and river ice processes in rivers are modified by climatic change, the use of empirical methods based on past observations and measurements could become less reliable. To advance beyond empiricism, it is necessary to develop rational design criteria based on a thorough understanding of the factors governing the interaction between bridges and ice. This concern applies especially during the breakup event when river flows, velocities, and hydrodynamic forces are usually higher and moving ice is thicker and stronger than during freeze-up. This paper provides guidance on the design of bridges to minimize ice impacts on the structure during the breakup period.Résumé : Le passage des glaces durant la débâcle peut avoir de nombreux effets sur la structure des ponts. La conception des ponts pour le passage des glaces était à ce jour largement empirique, comme la détermination du dégagement des superstructures conçues selon les données historiques. Alors que les processus hydrologiques et des glaces seront modifiés par les changements climatiques, l'utilisation de méthodes empiriques basées sur les observations et les mesures passées pourrait devenir moins fiable. Pour progresser au-delà de l'empirisme, il est nécessaire de développer des critères de conception rationnels, basés sur une compréhension approfondie des facteurs régissant l'interaction entre les ponts et la glace. Cela s'applique surtout durant la débâcle lorsque les débits, les vitesses et les forces hydrodynamiques des rivières sont généralement plus élevés et que la glace en mouvement est plus épaisse et résistante que durant la formation des glaces. Le présent article fournit des lignes directrices pour la conception des ponts afin de minimiser les impacts des glaces sur la structure durant la période de débâcle.

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Dynamic ice forces on piers and piles. An assessment of design guidelines in the light of recent research

Cited by 50 publications

References 0 publications

Laboratory experiments to study ice-induced vibrations of scaled model structures during their interaction with level ice at different ice velocities

Laboratory experiments to study ice-induced vibrations of scaled model structures during their interaction with level ice at different ice velocities

Modal Analysis of the Ice-Structure Interaction Problem

Hydraulic effects of ice breakup on bridges

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