Long Life Bridges
The Long Life Bridges project was a Marie Curie 7th Framework Project funded under the 2011 Industry and Academia Partnerships and Pathways call and ran from 2011 to 2015. The project, which was led by ROD-IS, focused on improving methods to increase the service life of bridges through the development of advanced Structural Health Monitoring methods. As a result of this project we have developed techniques to get more out of our transport infrastructure for less - more road and rail bridges being proven to be in a safe state, higher speeds on our (non-high-speed) railway lines with less demand for non-renewable and carbon intensive resources and for less cost.
The project focused on three key areas; Railway Bridge Dynamics, Life Cycle Evaluation and Fatigue Evaluation with the aim of;
Accurately quantifying the ‘true’ dynamic allowance for railway bridges with an acceptably low probability of exceedance using a probabilistic evaluation.
Developing a semi-active control system to create dynamic interference with train /bridge dynamic interaction.
Developing a probabilistic framework for fatigue design of steel bridges, including stochastic models for significant uncertainties.
Developing a framework for probabilistic life cycle evaluation of bridges, particularly new large cable stayed bridges.
As part of the work on Railway Bridge Dynamics, ROD-IS staff developed a prototype two-frequency tuned mass damper designed to account for the bridge response both during and after train passages. The properties and proportions of the damper were optimised using advanced Finite Element analyses and the prototype was subsequently tested and verified on the Ange Bridge, a steel bridge in Sweden. The damper was shown to attenuate the fatigue-related stresses by about 20% compared to the previous condition (i.e. based on the existing dampers on the bridge), ultimately representing an increase in the fatigue life of the bridge. In other activities in this work stream, ROD-IS staff developed vehicle-bridge interaction (VBI) models to assess bridge response on non high speed railway lines subjected to high speed train passage (v > 200km/h). The results of the analysis showed that including VBI in the analysis results in lower maximum accelerations, one of the key design parameter for high speed rail, indicating the potential for non high speed railway lines to carry high speed trains.
In establishing the framework for the life cycle evaluation, ROD-IS staff developed load models for long span bridges which integrated the bridge structure, wind load and traffic micro-simulation models. As a result of the research more accurate load models for traffic loading alone and traffic plus wind load interaction were developed which considered the actual traffic and wind as a coupled system. The complementary method of prediction of stochastic bridge loads proposed is recommended for predicting the performance of long and complex bridge structures under various combined loading conditions. Equally the overall procedure developed is flexible enough to allow the development of accurate site-specific multi-lane traffic and instantaneous multi-component wind load models. This is significant for the design of new bridges and has great importance for detailed fatigue analyses and bridge assessments.
Further information on the project can be found at www.longlifebridges.com