Browsing by Author "Weber, F."

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    A long-stroke semi-active MR damper for building control using tuned masses
    (National Information Centre of Earthquake Engineering, 2017) Zemp, René; Llera Martin, Juan Carlos de la; Almazán Campillay, José Luis; Weber, F.
    In this research the comprehensive development of a long-stroke MR-damper designed to control the earthquake performance of an existing 21-story reinforced concrete building in Santiago (Chile) by reacting on one of its tuned masses is presented. The ±1 m stroke MR-damper design is quite unique and considered the nominal response of the building equipped with two pendular masses of weight 160 tons each, and tuned to the fundamental mode of the structure. The realscale long-stroke MR-damper was designed by our research team and manufactured in Chile. The MR-damper was tested using a special testing rig designed to study devices with long stroke at large deformation velocities. The rig was implemented in the dynamics and vibration control laboratory at Universidad Catolica de Chile. Both, the long-stroke MRdamper and the control algorithm were experimentally validated using a suite of periodic and seismic signals. For the building numerical simulations, the nominal MR-damper force-displacement constitutive relationship was replaced by the measured force-displacement response of the damper in order to validate the theoretical MR-damper model used. Such model was used in simulations to predict the performance of the TM-MR damper assembly in the design phase of the damper. Furthermore, a new real-time structural displacement sensor was developed with this application since conventional technology and methods to measure building displacement are inaccurate for a real-time displacement control as proposed with this application. The real-time building displacement sensor was validated using a scaled-down building prototype subjected to shaking table tests before an actual size sensor was implemented within a test building. All electronic components of the tuned-mass MR-damper assembly were tested with a shaking table and subjected to strong motion accelerations while the MR-damper was working in its active mode. It is concluded that the proposed tuned-mass MRdamper solution is technically feasible and may be advantageous in some real-life situations. The stage of development of the technology reached a point that enables commercial implementation in a real structure.
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    Control of tuned masses using MR dampers and a new real time feedback signal and physical controller
    (2012) Zemp, René; Llera Martin, Juan Carlos de la; Weber, F.
    A scaled prototype of an MR damper was active in passive mode on a 160 ton tuned mass in a 21-story building in Santiago, Chile, during the February 27, 2010 earthquake. More recently, a full scale ±100 cm stroke MR damper was designed, manufactured, and is being tested for the same building. The implementation considers a new real time structural measurement system developed to acquire building displacements as feedback for the physical controller of the TM-MR damper assembly. The new measurement system was successfully tested on a shaking table model at Empa. Moreover, results from a number of nonlinear simulations on the building with the full scale semi-active damper shows that the mean displacement reduction for the setup considered is 22% more effective than the building with the bare tuned masses. Finally, the solution was identified to be fairly cost-effective as compared with a passive solution or the bare case