Research And Development Of A New Hysteretic Damper And Its Application Optimization

As one of the key component in high-rise shear wall structure,coupling-beam could directly affect the force distribution between walls and coupling-beams,further affect the damage under earthquake and failure mode of shear wall structure system.In order to realize the performance-based seismic design theory and meet the requirement of quick recovery after earthquake,the replaceable energy dissipative damper in high-rise shear wall structure was used more and more wide.Displacement-correlation damper mainly utilize the yielding of soft steel and the friction between metal interface to dissipating energy.In the structure of energy dissipative damper,the widely used mild steel damper had made great progress and development which has been developed from the original rectangular plate to a variety of different shapes and have different energy dissipative combinations.However,the energy dissipation principle of the above damper was single,and because of the limited energy dissipation capacity of a single plate,more space was required to obtain a ideal damping effect which lead to a lower economic efficiency.At the same time,it also lacks the contrast test of the widely used steel shearing damper for comparing weather the real hysteresis performance and failure mode was consistent with the theoretical calculation.In addition,the viewpoint of how to properly arrange the dampers and select the damper parameters in actual project was different among various scholars and there was no contrast of the damping effect in actual structures.To solve the above problems,the main work of this paper was as follows:In the first section,the current development situation was summarized,the concept and classification of energy dissipation technique and the energy dissipation principle were all introduced,in addition,several specific structure of the damper and the existing problems were also showed.In the second section,a new type of high-performance composite energy-dissipation damper with mild steel and lead core was presented.This type of the new damper could dissipate energy by both metal yielding and friction thus effectively increase the energy dissipation efficiency.The structure of the composite damper with the closely overlapped mild steel sheets and friction sheets also solved the problem that the flexural rigidity of a single common sheet was always too low.This structure also had the advantage of producing a more uniform stress state which could effectively avoiding the early damage especially focused on the edge of the dampers by tension and compression when bearing the moment.This composite damper had an excellent parameter adjustability and easy for repairing and replacement after earthquake for its bolt connection between every parts.In the third section,the most widely used steel shearing damper was studied.In view of the existing damper design process,there are a variety of component sizes can meet the requirement of the same yield strength and the same yield displacement.Six groups of the damper which have different damper height,plate strength and weld width were designed to study the different hysteresis property and failure mode.The test results showed that although the designed damper has the same yield force and yield displacement,it is very different from the test results.The effect of web steel can seriously be affected when the web height was too high,therefore,the height of the web should be strictly controlled.The quality of the weld line of the components,especially the weld line between flange and connection plate,web and plate can serious impact the failure pattern of the damper,in order to avoid the sudden change of stiffness caused by weld cracking and stress concentration,the thickness of the welding line should be increased.In the fourth section,the optimization of parameters and position of dampers in high rise shear wall structure was discussed.The damper stiffness,design ultimate displacement and additional damping ratio were set as basic parameters,inter-story displacement angle,story shear force and story acceleration were set as the damping effect evaluation index and the influence pattern of structural seismic response were obtained by comparing the different damper layout positions and quantities.This section verified that the changing of damper stiffness parameters,actual damper displacement and damper layout could have great influence on structure vibration period and additional damping ratio then further affect the damping effect.When energy-dissipative coupling beams were utilized to do seismic energy dissipation design in high-rise shear wall structures,we should first decorate the dampers to the places which bearing considerable loads then guarantee the damper's design yield displacement and ultimate displacement respectively matching the structure elastic inter-story displacement and the elastoplastic inter-story displacement.During the design processes,the vibration period of the structure was supposed to be extended and the additional damping ratio was supposed to be maximized by adjusting the damper stiffness,damper layout position and quantity.The results showed that the seismic capability can be greatly improved though the dampers slightly increased the cost.The fifth section was the conclusion and the prospect.Firstly,the research contents and relevant conclusions of this paper were summarized,then,the prospect was finally put forward.