We are the structural dynamics consultant for the Engineer of Record responsible for a large observation wheel...one of the largest observation wheels in the world. We evaluated the wind force time histories provided by the wind tunnel laboratory to determine the worst-case conditions for Wheel operation and storm events, predicted the wind-induced dynamic response of the structure for occupant comfort on typical windy days, and supported the Structural Engineers in their assessment of structural safety under worst-case storm conditions including the dynamic magnification effects of the structure.
Tuned mass dampers incorporated into A-frame provide a reduced vibration environment for the occupants and structural member force mitigation during storm events. We are also tasked with predicting the dynamic performance of the structure with and without the TMDs and for defining critical performance requirements for the TMD design agent. In addition to the baseline TMDs located in the A-Frame, we investigated alternative TMD configurations and placement within the Wheel's rim that can simultaneously control the sway and torsion modes of the structure.
We perform structural dynamics analyses for all kinds of systems. If it moves or vibrates, we can analyze it. Pump and fan manufacturers, such as Verantis, are often required to provide a structural dynamics resonance frequency assessment of their system to ensure it is dynamically compatible with the structure it will be mounted on. The pump and the structure act together as a dynamic system, so a proper structural dynamics analysis must be performed to understand the system performance.
We also work with industrial clients with unique concerns in the structural dynamics area. Large fluid-filled tanks can present some very challenging design problems when seismic forces must be considered. The fluid sloshing modes can interact with the structural modes of the supporting frame and lead to elevated forces that must be accounted for in the design of the frame. These forces cannot be estimated accurately using the simplified seismic analysis procedures in the Building Code.
Structural dynamics analyses of floor systems are needed to predict their vibration response to people walking through the space, internally-generated mechanical systems, and to externally-generated sources such as traffic on nearby roadways.
When we design tuned mass dampers to reduce the vibration levels on a section of a floor, we develop a structural dynamics model of the floor system and then fine-tune the model to match our vibration measurements of the floor's primary resonance frequencies. This validated model is then used to assess the effectiveness of the proposed tuned mass dampers.