Author(s): P. Kujala; K. Riska; P. Varsta; R. Koskivaara; T. Nyman
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Abstract: A new loading rig was developed to conduct four point bending tests of floating ice beams. Results from the tests in the Gulf of Finland near Porkkala pilot station in February 1985 are presented. The length of the tested beams were about 4.3 m, breadth 0.35 m and thickness about 0.4 m. In total 34 beams were tested with success, surface temperature of the beams varying from -1.0 to -8.3°C and salinity from 1.9 to 3.6ppt. The strain rate in the tested beams were in the range of. .. . The flexural strength values measured with tension at the top surface varied in the range 0.38-0.89 MPa with mean of 0.58 MPa. The effective elastic modulus achieved values in the range 3.2 - 5.4 GPa with mean value of 4.1 GPa. The beams tested upside down gave about 20 % smaller values for the flexural strength. The short analysis revealed the important effect of vertical temperature gradient on the results obtained from bending test of floating ice beams for the elastic and strength properties of ice. A correction curve was formulated to calculate the ratio between tensile and flexural values of elastic modulus and strength as a function of top surface temperature of the floating ice beams tested. The ratio between tensile to flexural value was found to vary from 1 to 2.3 for the elastic modulus and from 1 to 1.7 for the strength at the top surface when the surface temperature changes from -1.0 to -10 °C. Thereafter the measured value was 0.88 MPa for the tensile strength and 7.2 GPa for the elastic modulus at the top surface with surface temperature of -5 °C.
Year: 1990