Soil Dynamic And Seismic Loads
Ground vibration is a field of structural dynamics that requires a special set of skills. Ground vibration is in essence very similar to travelling waves in the sea. Only, the ground differs from the water in the sea in the way that it must be treated as an elastic medium, where both normal and shear stresses are found. Hence, an array of different wave phenomena can be encountered including shear waves, interface waves, and surface waves. In order to model these phenomena an in depth understanding of continuum dynamics is required.
Svend Ole Hansen ApS and SOH Wind Engineering have been involved in analysis of ground vibration in many different projects. Svend Ole Hansen ApS has performed various analysis of vibration transmission from heavy traffic, including railways, to neighboring buildings. In particular the design of cleanrooms that have very rigorous requirements regarding the acceptable level of vibration may require an analysis of ground vibration. Svend Ole Hansen ApS has also been involved in the design of vibration mitigation measures concerning ground vibration. Mitigation measures can include trenches to reduce the intensity of surface waves or more traditional vibration insulation measures in the foundation structure of buildings. The design and application of structural dampers is also a core competence of Svend Ole Hansen ApS.
A special field within ground vibration is the analysis of seismic action. Generally, structures must be designed regarding the effect of seismic action. Usually, a level of vibration is set by the code for the deeper layers of the ground i.e. the bed rock. The engineering task is then to translate the vibration at this level into actual inertial actions in the structure. The task is in essence to determine the dynamic amplification of the upper ground layers and the structure itself.