| Summary: | 碩士 === 國立交通大學 === 土木工程系所 === 98 === In this study, both the frictional damping brace and seismic friction wall have been developed based on a special alloy. A series of component tests and seismic performance tests have been conducted. Component tests indicate that the proposed alloy-based friction dampers possess rate-independent stable and rich hysteresis loops with characteristics of the Coulomb’s friction mechanism. The frictional coefficient (μ) between the special alloy and steel is high. It may exceed 1.0 if properly designed, higher than those for the existing friction dampers. As a result, the capacity of the friction dampers can be substantially increased. From a practical point of view, the key to the success of friction-type damping devices is the ability to precisely manage the frictional coefficient and normal force (i.e. tensile force in the bolts). The tensile forces in the bolts are linearly related to the torques. Calibration tests indicate that the torque-to-tension ratio of the bolt is constant, regardless of the bolt diameters. This would be helpful in practical design of the friction devices. Seismic performance tests show that, the frictional damping braces significantly enhance the equivalent damping ratios of the structure in the lower vibration modes while amplify the high frequency responses. Fortunately, the overall structural responses are reduced as the participation factors for the higher modes are low. The effectiveness of the frictional damping braces increases with the earthquake intensity. Simulation results indicate that ETABS can sufficiently simulate the coulomb’s friction mechanism. The predicted seismic structural responses agree well with the test results, despite of the fact that discrepancy still exists. The source of errors possibly comes from neglecting the H-beam braces in the modeling, which results in over-estimation of the stiffness as the friction dampers are in non-sliding states.
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