CressHelp - Ice forrces - Forces on vertical structures

Cress Help - Ice forces - Forces on vertical structures - A21.9

Velocity ice known

Forces on vertical structures:

Ice forces exerted by floating ice on a vertical structure with a contact width of ca. 2 m can be calculated with the equation of Korzhavin [g]. This equation is valid for ice velocities from ca. 0.5 m/s and has been validated to ca. 1.5 m/s.

equation 1

With :

equation 2

In which :

b: width of the structure in the path of the ice [m]
F: horizontal force on structure caused by floating ice [N]
h: thickness of ice cover [m]
k: contact coefficient = -0.2Vice - 0.020b + 0.86 [-] This equation is derived from of data in the literature
m: shape factor of pier/structure = 0.392(1 + á ð/180) [-]
Vice : velocity of ice field/floes [m/s]
a: angle between the tangents of the point of contact with the structure [°] For a rounded structure: a = 70 °.

sc: cubic compression strength of ice (= ca. 3105 N/m2 for Dutch conditions) [N/m2]

s1: cubic compression strength of ice if Vice = 1 m/s [N/m2]

At lower velocities of Vice < 0.5 m/s the average force during the collision of the ice flows with the structure can be estimated from the equation of forces:

References
[a] ing. C.J.A. Zijlmans, IJsbezetting -bestrijding op de grote rivieren in Nederland, Literatuurstudie, Rijkswaterstaat, Dir. benedenrivieren, afd. AXB, org. IJsopruiming, sektie onderzoek, nov. 1980.
[b] Stormvloedkering Nieuwe Waterweg, document ontwerp, deel 1, RWS Directie sluizen en stuwen, 31 juli 1989, BMK.
[c] ir A.W. de Haas, april 1986, Ice afvoerproblematiek voor de grote rivieren en de Rijndelta, bijzondere onderwerpen, RWS dir. Benedenrivieren, Organisatie IJsopruiming Sectie Onderzoek.
[d] ir T. Stoutjesdijk e.a. Grondmechanica Delft, oktober 1991, Taludbekledingen van gezette steen, bijzondere belastingen, co-320030/3.
[e] H.R. Kivisild, Proceedings 8th IAHR-congres 1959, Montreal-Canada-Volume III, "Ice problems in hydraulic structures.
[f] ir F. Gerritsen, Proceedings POAC-conference "The first international conference on port and ocean engineering under Arctic conditions", Vol. I Norway 1971, Ice problems in Dutch rivers and estuaries, blz. 582 e.v.
[g] Korzhavin, K. N., Action of ice on engineering structures, Novosibirsk, Akad. Nauk. USSR 1962.Vertaling: TL 260 van CRREL Hanover, New Hampshire, 1971
[h] Russische ontwerpregels uit 1986.
[i] Carstens T. editor, Working group on ice forces on structures, A State-of-the-art report, special report 80-26, june 1980.