Structural Dynamics Research Projects

Dissipative Devices in Seismic Design

Jarret Device

We have conducted extensive experimental testing and modelling of hysteretic and fluid viscous energy dissipators for improving the seismic performance of frames. Current research is focused on the development of optimal placement strategies for viscous dampers to enable a building to meet specific performance objectives subject to constraints of practicality. We also have plans to extend our work to elastomeric dampers, buckling restrained braces and other novel devices. 

Development of High Seismic Performance Steel Frames

Conventional structures are designed to suffer significant damage under strong earthquakes. Damage results in repair costs and business interruption whilst the building is repaired and cannot be used or occupied. In this project we are developing an innovative seismic-resistant structure with the potential to overcome the socio-economic risks related to earthquakes by resisting: (a) moderate earthquakes without damage; and (b) strong earthquakes with easy-to-repair damage. The project will develop design methods for the proposed frame by conducting integrated analytical and experimental research. The final goal is to provide structural engineers and building owners with new technology to build resilient minimal-damage structures.

 

 

Development of Real-Time and Distributed Hybrid Test Methods

 
Distributed Hybrid Testing

We played a leading role in the development of the real-time hybrid test method, in which the structure under test is split into a physically tested part and a numerically modelled part, with the physical and numerical components connected throughout the test by a real-time control loop. This technique allows more realistic simulation of structural behaviour under dynamic loads without the need for exceptionally large and expensive laboratory facilities, and is now being adopted in seismic test laboratories across the world.

More recently, we have developed a distributed hybrid test technique, in which the structure is split into several components tested in different laboratories which may be geographically remote from each other, with data passed between them over the internet as the test proceeds. With colleagues at Bristol University, we have performed what are believed to be the world's first real-time distributed seismic tests.

Dynamics of Piles and Pipelines in Liquefiable Soils

Text awaited

Development of Advanced IT Tools for Collaborative Earthquake Engineering

 
Series Virtual Database

Working with several European partners, we are using the techniques of e-science to improve collaborative research in earthquake engineering. This includes the development of an innovative virtual database, allowing worldwide access to research results, use of video-conferencing and real-time video streaming of experiments, and further development of the distributed hybrid test method.

This work is part of the EC FP7 project SERIES (Seismic Engineering Research Infrastructures for European Synergies), a large, pan-European collaborative project coordinated by University of Patras.

Grandstand Vibrations and Human-Structure Interaction

 
lateral dynamic force

Many modern structures such as footbridges and sports stadia have become highly susceptible to vibrations induced by crowds even when they perform normal daily activities such as walking, dancing and sitting. Our early work in this area focused on the vertical loads crowds exert on structures, and on group synchronization effects. We are now addressing the current lack of information on the lateral loads crowds impose on slender structures, an issue that was highlighted by the much publicized problems of the iconic London Millennium Footbridge structure almost a decade ago. This research will provide important lateral load data which will be of direct interest not only to structural engineers involved in the design of such structures but also to the authorities responsible for licensing and inspection of the affected structures.

Stability and Dynamics of Historic Masonry Construction 

This project is currently focused on the Basilica of Maxentius in Rome, a massive Roman concrete vaulted structure built between 307 and 313 AD. Using methods based on Heyman's limit analysis approach, we are attempting to understand the partial collapse of the structure (believed to be caused by an earthquake in the middle ages) and to explore the seismic safety of the remaining portion.

Other Recent Projects

Seismic analysis of guyed masts: Extensive finite element modelling of guyed masts assessed their seismic vulnerability and identified cases where the earthquake load case could be more critical than wind.

Statistical modelling of crowd loads: We developed a statistical model of crowd jumping loads, which took account of the inherent variability between people, and between a sequence of motions performed by an individual. We showed that taking these effects into account could lead to reductions in design loads in excess of 30%.

Assessing crowd loads through video tracking: We used computer vision techniques to track head motions of groups of jumping/dancing people, and built a model which related these to the loads they imposed on the floor, enabling an initial estimate of dynamic group loads to be made from simple video footage.

Dynamics of forklift trucks: We developed a dynamic load model of a forklift truck, for use in vibration analysis of suspended warehouse floors.

Dynamic characteristics of prestressed concrete floors: We have performed extensive field testing and finite element modelling of prestressed concrete floors, in order to assess their susceptibility to vibration problems caused by human footfall and indoor vehicles.