MODEL TESTING OF RIDGE KEEL LOADS ON STRUCTURES PART IV: PRELIMINARY RESULTS OF FREEZE BONDSHEAR STRENGTH EXPERIMENTS

摘要

A series of experiments intended to study freeze-bond strength in model ice were performed inrnthe Hamburg Ship Model Basin (HSVA) during November 2008. The ice used in the experimentsrnwas the same model ice used to build the model ridges described in Part II of the publications.rnFreeze-bond strength in direct shear was measured as a function of initial ice temperature,rnavailable time to develop the freeze-bond and normal stress applied to the freeze bond samples.rnFreeze-bond strength was also measured in rafted layers from the model ice ridges. A total of 58rnexperiments divided into four series were performed. The results from the controlled experimentsrnand the freeze-bonds from the model ridges indicate that the former are representative of thernactual phenomena happening in the model ridges. A decreasing tendency of the freeze-bondrnstrength versus increasing submersion time was found, which agrees with previous results fromrnfull scale tests. A slightly decreasing tendency of freeze-bond strength with decreasing initial icerntemperature was found. This does not agree with previous observations. The variation of freezebondrnstrength versus normal stress showed an increasing tendency with increasing normal stressrnuntil a normal load of 1200 Pa where the freeze-bond strength decreases.