Ice in contact with marine structures cause abrasion of surfaces. The widely differing concrete surface roughness may cause high short-time contact pressure. Water between ice and concrete can then be pressed into the subsurface pores. The indentation contact area determined as function of pressure, concrete surface roughness and mechanical properties of concrete and ice can be used to determine water penetration depth. This paper shows the proposed model and that it can predict observed abrasion for properties of permeability, tensile strength, ice movement, pressure and number of contacts.
A quarter of the world undiscovered petroleum resources can be located in the Arctic and Far-Eastern seas. The plans of exploration of these areas make actual the problems of ice forces effect on structures on more severe conditions as were met earlier. There are three limiting states which govern GBS behavior under ice actions:
- strength and stability of GBS and its elements under ice forces
- deformations of GBS and its elements influencing on the workability
- fatigue strength of GBS elements. Ice mechanics and numerical simulation of ice-structure interaction are major research interests today.
One of the research topic is ice abrasion relating to third limiting state. Ice movement can cause severe abrasion of coastal and offshore concrete structures such as gravity base structures (GBS), marine bridges, piers, sea wind mill foundations or concrete dams in rivers. The operation experience of platforms in the Sea of Okhotsk show that the ice abrasion is dangerous phenomena and can cause the material destruction in water level. Ice can also act in the pores of concrete as hydraulic pressure (Powers, 1945), as a propagating ice front in a concrete frost test or due to different thermal expansion coefficients concrete-ice. This abrasion can affect the service life and precautions are therefore necessary when designing and producing concrete structures for the arctic.