THE EFFECT OF USING ARC-SURFACED DAMPERS ON REDUCTION OF THE COLLAPSE PROBABILITY INDUCED BY FORWARD DIRECTIVITY

Sara Balzadeh | Zakariya Waezi

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URL :   http://research.shahed.ac.ir/WSR/WebPages/Report/PaperView.aspx?PaperID=116839
Date :  2019/09/14
Publish in :    هشتمين کنفرانس بين‌المللي زلزله‌شناسي و مهندسي زلزله


Keywords :ارزيابي فروريزش، جهت پذيري پيش رونده، ميراگر اصطکاکي، نيروي اصطکاک متغير، ميراگر سطح-قوسي

Abstract :

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The friction dampers have long been used for control of the structures against being damaged due to earthquake excitation. However, since these dampers possess constant friction forces they cannot play a significant role in mitigation of the strong earthquakes’ demands and they should be optimally designed for each specific excitation in order to perform properly. Application of the friction dampers whose forces are variable is one way of circumventing this problem. In this paper, the design parameters of a specific force-variable friction damper namely Arc-Surfaced Friction Dampers (ASFD) have been investigated and their effect on the efficiency of their performance have been assessed. To this end, a 4-story structure designed according to Iranian Building Code Standard-2800 equipped with an ordinary frictional damper(LSB) with constant sliding force and an ASFD have been excited by an ensemble of near- and far-field ground motions. In order to determine the optimal ASFD parameters, which in here reflected as the initial sliding force and the radius of curvature of the ASFD, the response of the structure due to 44 FEMA-p695 ground motions scaled to the elastic design spectra corresponding to 10 of exceedance in 50 years are estimated. The nonlinear dynamic analysis have provided a basis to define the optimal parameters with respect to the life-safety and collapse-prevention performance. The results showed that implementing the ASFD as a control device has significantly reduced the median spectral acceleration corresponding to onset of collapse compared to the bare uncontrolled structures.