Frost heave testing of norwegian materials for road infrastructure

In areas of seasonal frost, frost susceptibility composed by frost heaving during the winter and thaw softening during the spring is one of the most dangerous phenomenon for transportation, road and railway infrastructure. Therefore, the need for frost protection layer becomes imperative. The purpose of frost protection layer is to prevent frost from penetrating down through the pavement and into the sub-soils. Frost susceptible soils under the road can be cause damages on the roads or other structures due to frost heave or reduced capacity characteristics thaw period. "Frost heave" is the term given to the upwards displacement of the ground surface caused by the formation of ice within soils or aggregates (Rempel et al., 2004). Nowadays in Scandinavia the most common material used in frost protection layer in the pavement structure of roads and in the ballast of the railway tracks are coarse-grain crushed rocks aggregates. Based on the capillary rise, the mechanics of frost heave phenomenon is based on the interaction between aggregates and water, as suggested by Konrad and Lemieux in 2005 that said that the fraction of material below the 0.063 mm sieve for coarse-grained soils must be controlled so as to reduce the sensitivity to frost heave. The study conducted in this thesis project is divided in two parts: - the analysis of the coarse grained aggregates used in frost protection layer in Norway; - the analysis of the frost heave phenomenon in the laboratory under known boundary conditions, through the use of the most widely used method, the frost heave test, in” closed system” (without access of water).

Boundary condition identification of a bridge pier using experimental data and FEM modal updating

Over the past twenty years, new technologies have required an increasing use of mathematical models in order to understand better the structural behavior: finite element method is the one mostly used. However, the reliability of this method applied to different situations has to be tried each time. Since it is not possible to completely model the reality, different hypothesis must be done: these are the main problems of FE modeling. The following work deals with this problem and tries to figure out a way to identify some of the unknown main parameters of a structure. This main research focuses on a particular path of study and development, but the same concepts can be applied to other objects of research. The main purpose of this work is the identification of unknown boundary conditions of a bridge pier using the data acquired experimentally with field tests and a FEM modal updating process. This work doesn’t want to be new, neither innovative. A lot of work has been done during the past years on this main problem and many solutions have been shown and published. This thesis just want to rework some of the main aspects of the structural optimization process, using a real structure as fitting model.