Assessment of ice loads on piled structures based on local conditions

Abstract: This master report studies structural design methods for ice loads and the impact of local conditions. Ice loads occur due to ice movements or expansion of the ice sheet. Specifically, this study analyses ice loads on piled structures and ten different design methods and handbooks to calculate the ice load. There are five Swedish methods among these, and the remaining are developed in Denmark, Finland, Norway, and Germany. The methods are developed for different types of structures. For example, dams, bridge supports, traffic piers, ports and piles The ice loads have been divided into different categories; vertical ice loads and horizontal loads caused by thermal expansions, water level changes, or drifting ice. Some methods depend on local conditions parameters for the input data. These methods have been investigated in a parametric study to shed light on how different inputs affect the ice load. Some input data from local conditions have been developed and are presented to facilitate the design. Temperature and ice thickness are the parameters where most data are accessible. Furthermore, an evaluation has been performed on whether the methods are applicable for piles, if local conditions are considered, and if the method is practically applicable for ice load design. The size of the ice load is reported for different ice load types for three Swedish cities, namely Halmstad, Mora and Umeå. The overall result was that Mora generated the highest ice load magnitudes and Halmstad the lowest. A Finite Element (FE) analysis has been performed to address the affect that ice loads have on the dimensions of the piles. In general, more knowledge is needed about ice loads and their magnitude. Studies on what safety factors are included in each method need to be carried out to counteract unnecessarily applied safety factors in several stages. In addition, studies from a statistical perspective are required, where the return period of the input data used in the methods is studied. A statistical study would evaluate which values are justified in relation to the return period of the ice load.