Figure 8 Relationship between the flexural strength and the ice temperature
Figure 9 Relationship between the compressive strength and the ice temperature
4. Conclusion
The results of the field experiments can be summarized as follows.
(1)Four kinds of floating bodies were installed in the No. 4 basin for small craft and observed in experiments from mid January to mid March, 1996. From late January to early February, ice covered the surface of the No. 4 basin, thawed and flowed away repeatedly. The surface of the basin was completely frozen over on February 8. On March 8, the ice began to thaw and had completely flowed away from the port by mid March.
(2)When the floating body was installed 2 m from the quay wall, its displacement (angle of tilt) was larger than for the case of 10 m, being affected more by flexural failure of the ice floe.
(3)When the side walls of the body were tilted, the displacement (angle of tilt) was larger than for the body with upright side walls, because the body with tilted side walls was affected unevenly by the vertical movement of the ice floe caused by the changing tide level.
(4)When the floating body was white, the displacement(angle of tilt) was larger than that for the black body, because the white body was affected unevenly by the vertical movement of the ice floes caused by the changing tide level.
(5)The following points should be taken into consideration when designing floating structures in cold regions.
?The floating body should be installed out of the range where the ice floe undergoes flexural failure near the quay wall, to prevent the body from tilting too much.
?It is preferable that the floating body is with upright side walls and is black, to prevent the body from tilting unevenly.
?The floating body needs to be corrosion proofed, since some peeling of the paint and corrosion on the surface were found after the experiments.
?The floating bodies were moored by the anchor method for the experiments, but the pile-type method or the dolphin method are more desirable to decrease the horizontal displacement.
(6)Floating bodies can be effectively used in winter for fishing and walking if these findings are taken in to consideration for their design. The following two points need further examination for the use of marinas in winter.
?Countermeasures for wind, cold, etc.
?Safety measures
References
Sasajima, Mizuno, Terashima, Kawai and Sacki, 1995, Designing Methods of Marinas Constructed in Cold Regions, Proceedings of Civil Engineering in the Ocean, Vol. 11.
Sasajima, Hayakawa, Terashima, Yoshida, Hamaoka and Saeki, 1996, Influence of Ice upon Floating Structures Constructed in Cold Regions, Proceedings of Civil Engineering in the Ocean, Vol. 12.
