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Kuhlmann W.,Offentlich Bestellter und Vereidigter Sachverstandiger IKBau NRW fur Baudynamik | Dalmer F.,GERB Schwingungsisolierungen GmbH and Co. KG | Gokus S.,Projektingenieur Fachbereich Baudynamik
Bauingenieur | Year: 2011

Due to their slenderness footbridges are especially vulnerable to vibrations. The vibrations induced by pedestrians therefore have to be limited to an extent that is not perceived as unpleasant. To sustain the aesthetics of architecturally high-quality constructions tunes mass dampers are an ideal tool for vibration reduction because they can be installed in such a way that they do not appear visually. The design of the tuned mass dampers is carried out based on the dynamic parameters of the vibrating bridge. In doing so, the different modes of vibration of the bridge structure have to be considered, i.e. vertical, lateral and torsional vibrations. If these modes are close to each other special requirements of the design of the tuned mass dampers apply. In this article it will be explained using the example of the two Skywalks in Berlin main station how such combined bending and torsional vibrations can be reduced by optimized designed tuned mass dampers. Source


Siepe D.,GERB Engineering GmbH | Meinhardt C.,GERB Schwingungsisolierungen GmbH and Co. KG
Proceedings of the 8th International Conference on Structural Dynamics, EURODYN 2011 | Year: 2011

The contribution introduces the practical application of Tuned Mass Control Systems (TMCS) for earthquake protection of highway bridges. Optimization approaches for these passive control systems will be discussed as well as practical considerations regarding the resulting specification of the TMCS. For the discussion, theoretical approaches will be introduced and results of additional numerical calculations will be presented to verify the reduction due to the control system. Furthermore, the experimental investigations of a TMCS for a steel frame structure are presented. The contribution also introduces the practical application of a TMCS at an elevated bridge structure and presents design solutions for these systems. For this project several numerical calculations (response spectrum analysis/time domain analysis) have been performed to theoretically verify the introduced optimization approaches and to assess the practicability of the resulting TMCS specification regarding nonlinearities due to the structural degradation of the structure during seismic loading, such as the decrease of structural stiffness and the increase of structural damping due to cracks and local damages. The methodology of ambient vibration test after installation will also be presented. These tests will be necessary to determine all relevant dynamic parameters, to verify the relevant mode shape and to document the increase of structural damping due to the activated TMCS. In this context, the Random Decrement Method, as a suitable damping assessment technique, will be introduced. According to the numerical results a significant reduction of the structural response due to seismic loads can be expected. Source


Meinhardt C.,GERB Schwingungsisolierungen GmbH and Co. KG | Yin X.,GERB Qingdao Vibration Control Co. | Luo Y.,GERB Qingdao Vibration Control Co. | Gao X.,GERB Qingdao Vibration Control Co.
Bridge Maintenance, Safety, Management and Life Extension - Proceedings of the 7th International Conference of Bridge Maintenance, Safety and Management, IABMAS 2014 | Year: 2014

This paper presents a practical project example for the successful application of 32 Tuned Mass Dampers (TMDs) to the Chong Qi Bridge in China (total length 7km - main bridge span 944 m) to reduce vortex shedding induced oscillations of the bridge's girder sections (section span 184 m). The application of such devices is a beneficial alternative to aerodynamic and aeroelastic optimization of the bridge deck by increasing structural damping to reduce the vertical dynamic response for the case that vortices shed off with a frequency that corresponds with the fundamental vertical bending frequency of the bridge. While aerodynamic measures only shift the critical wind speed for which these resonance effects occur, passive TMDs reduce the bridge's dynamic response. In detail, this contribution describes the TMD concept and the realized optimization of the Tuned Mass Damper units to achieve an optimum reduction effect whilst reducing the mass additional mass that has to be applied to the bridge. Results of preliminary work shop tests will be presented as well as the experimental dynamic analysis of several bridge segments that has been performed during the commissioning of the TMD. This analysis included the determination of the bridges relevant vibration modes and the corresponding structural damping from ambient vibration tests using several system identification techniques such as FDD, SSI and Rand Decrement Method algorithms. Especially the damping values of the bridge are within the scope of interest to verify the optimum performance of the applied TMD systems. In addition the interaction between bridge and TMD has been monitored also under ambient wind loading. Therefore an approach to additionally assess the effectiveness of the systems will also be introduced. © 2014 Taylor & Francis Group. Source


Jaquet T.,GERB Schwingungsisolierungen GmbH and Co. KG
Notes on Numerical Fluid Mechanics and Multidisciplinary Design | Year: 2015

This paper describes studies associated with planning for a new Metro Line in close vicinity to heritage buildings in the historic heart of Beijing requiring strict compliance with vibration criteria. To minimize uncertainties, extensive measurements were performed, including borehole tests to assess local soil properties. Furthermore, the influence of several key design factors on the final results is analyzed. The importance of long-term design and installation experience of highly efficient FST is illustrated © Springer-Verlag Berlin Heidelberg 2015. Source


Meinhardt C.,GERB Schwingungsisolierungen GmbH and Co. KG | Siepe D.,GERB Engineering GmbH | Nawrotzki P.,GERB Schwingungsisolierungen GmbH and Co. KG
Seismic Isolation and Protective Systems | Year: 2011

This contribution describes the practical application of tuned mass control systems (TMCS) to bridges and buildings. Besides the experimental verification of significant reduction effects, results the results of a theoretical analysis that document the achievable improvements on the seismic response even in case of large structural damping ratios, is presented. Optimization approaches for these passive control systems will be discussed as well as practical considerations regarding the resulting specification of the TMCS. For the discussion, theoretical approaches will be introduced and results of additional numerical calculations will be presented. Design considerations for the selection of the parameters of the TMCS that take into account the nonlinearities due to the possible decrease of structural stiffness and the increase of structural damping due to cracks and local damages, will be discussed as well. In the context of TMCS, two example projects will be introduced. One example explains the application of TMCS systems to a low damped elevated bridge structure and design solutions for these systems are presented as well as in-situ test methodologies to verify the increase of structural damping. The other example describes the application of TMCS systems as part of a consolidation strategy to successfully retrofit a large RC-structure / masonry wall building. Results of numerical calculations-verified by insitu ambient vibration measurements-that examine the reduction effect of the TMCS in combination with additional measures will be shown together with cost effective design solutions. © 2011 Mathematical Sciences Publishers. All rights reserved. Source

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