Estimating ice forces on a bridge pier using field observations and a deformation model

This technical note qualitatively and quantitatively described the ice run that took place in Sokna river, Trøndelag, Norway on the 23rd of January 2020. Metrological and hydrological data is described. Stranded ice floe size distribution data is presented and analysed. This shows that the maximal ice floe dimension is well described by generalized exponential (shape=2.77,scale=1.42) or log-logistic distributions (alpha=3.57,lambda =1.15). A custom-built steel load panel had been mounted on Sokna bridge preceding the ice run, however due to technical difficulties no forces were recorded. Hindcast calculations using Solidworks based on the permanent deflections experienced by this load panel have been carried out to estimate ice forces experienced by Sokna bridge. These show that the real peak ice force experienced by the 0.8m i diameter cylindrical bridge piers must have been within the range 1.1-5.5MN. This range is compared to predictions made by standards for predicting ice forces on bridge piers.