scholarly journals Seismic Performance Evaluation of Building-Damper System under Near-Fault Earthquake

2020 ◽  
Vol 2020 ◽  
pp. 1-21 ◽  
Author(s):  
Xiaoli Wu ◽  
Wei Guo ◽  
Ping Hu ◽  
Dan Bu ◽  
Xu Xie ◽  
...  
Keyword(s):  
Seismic Performance ◽  
Structural Damage ◽  
Pulse Velocity ◽  
Friction Damper ◽  
Pulse Period ◽  
Earthquake Excitation ◽  
Seismic Code ◽  
Velocity Amplitude ◽  
Near Fault ◽  
Near Fault Earthquakes

The building-damper system designed by a seismic code is usually considered to be able to withstand the attack of strong earthquakes. However, near-fault earthquakes, especially those with the forward-directivity effect, might cause early and unexpected failure of code-designed dampers and consequent severe structural damage. In this paper, by taking into account near-fault earthquakes, seismic performance of the building-damper system and damper failure’s influence are evaluated systematically. A 9-storey steel building is designed by the Chinese seismic code as the benchmark model, and five typical dampers, including buckling-restrained brace damper (BRB), friction damper (FD), self-centering damper (SCD), viscous damper (VD), and viscoelastic damper (VED), are adopted. It was found that the building-damper systems show a large response and possible damper failure under the near-fault earthquake excitations. Then, the influence of damper failure is investigated, which reveals that damper failure would significantly affect seismic performance of the building-damper system, especially for the building-SCD system. Subsequently, by introducing the artificial near-fault earthquake excitation, the influences of different pulse parameters, such as pulse velocity amplitude, pulse period, and the number of significant pulses, are studied. It shows that the pulse velocity amplitude and pulse period obviously affect the seismic performance, while the number of significant pulses presents little influence.

scholarly journals Fuzzy Control for Seismic Protection of Semiactive Base-Isolated Structures Subjected to Near-Fault Earthquakes

2015 ◽  
Vol 2015 ◽  
pp. 1-17 ◽  
Author(s):  
Dahai Zhao ◽  
Yongxing Li
Keyword(s):  
Fuzzy Logic ◽  
Fuzzy Logic Controller ◽  
Fuzzy Controller ◽  
Seismic Protection ◽  
Friction Damper ◽  
Design Spectrum ◽  
Near Fault ◽  
Isolated Structures ◽  
Near Fault Earthquakes ◽  
Elastic Design

This paper proposes a new fuzzy logic controller, which is designed for seismic protection of base-isolated structures utilizing piezoelectric friction damper against near-fault earthquakes for different ground sites. According to the elastic design spectrum that Eurocode 8 recommends, one 5% damped elastic design spectrum for Chi-Chi earthquake is proposed to generate artificial earthquakes of different ground sites. The proposed controller employs a hierarchic fuzzy control algorithm, in which a supervisory fuzzy controller governs a sublevel fuzzy controller by altering its input normalization factors according to current level of ground motion. In order to simultaneously reduce the base displacement and superstructure responses of the base-isolated structure during seismic excitations, genetic algorithm is employed to optimize the supervisory fuzzy controller and the preload of piezoelectric friction damper. The efficiency of the proposed controller is also compared with passive controller and a linear quadratic Gauss optimal controller. Numerical results show that the proposed fuzzy logic controller has favorable performance in mitigating the responses of the base-isolated structure.

scholarly journals Major Parameters Affect the Non-Liner Response of Structure Under Near-Fault Earthquakes

2019 ◽  
Vol 5 (8) ◽  
pp. 1714-1725
Author(s):  
Ali Abdulwahid Mohsin ◽  
Hussam K. Risan
Keyword(s):  
Response Spectrum ◽  
Actual Behavior ◽  
Pulse Period ◽  
Period Increase ◽  
Directivity Effect ◽  
Near Fault ◽  
Individual Record ◽  
Two Factors ◽  
American Society ◽  
Near Fault Earthquakes

Near-fault ground motion can be identified by the presence of a predominant long duration pulse in the velocity traces mainly due to directivity effect. This pulse exposes the structure to high input energy at the beginning of the earthquake which leads to a higher response in comparison with the ordinary ground motions. This paper investigates 79 earthquake records with different properties to achieve three goals: the first aim is to compare between the linear and nonlinear response of SDOF systems under near-fault and far-fault earthquakes. While the second objective is to examine the parameters that control the characteristics of near-fault earthquakes. Two factors have been studied which is PGV/PGA ratio and pulse period. Finally, the seismic code provisions related to the near-fault earthquakes were evaluated in term of the elastic acceleration response spectrum, the evaluation is adopted for American Society of Civil Engineers code ASCE 7 and Uniform Building Code UBC. The results lead to the following conclusions: with respect to a specific PGA, the near-fault earthquake imposed higher response in comparison with far-field earthquakes. The near-fault earthquakes become severe as the PGV/PGA and pulse period increase. The interested seismic codes can cover the actual behavior based on the average response of a certain amount of data, while it may become non-conservative relative to an individual record.

scholarly journals Seismic Performance of Steel Structure-Foundation Systems Designed According to Eurocode 8 Provisions: The Case of Near-Fault Seismic Motions

Buildings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 63 ◽  
Author(s):  
Panagiota Katsimpini ◽  
Foteini Konstandakopoulou ◽  
George Papagiannopoulos ◽  
Nikos Pnevmatikos ◽  
George Hatzigeorgiou
Keyword(s):  
Seismic Performance ◽  
Time History ◽  
Steel Structure ◽  
Steel Structures ◽  
Eurocode 8 ◽  
Near Fault ◽  
Building Foundation ◽  
Steel Building ◽  
Near Fault Earthquakes ◽  
Nonlinear Time History

The seismic performance of steel structure-foundation systems subjected to near-fault earthquakes was assessed on the basis of response results from nonlinear time-history seismic analyses. The structural results included the maximum values for residual interstory drift ratios, base shears, and overturning moments of the steel structures, as well as the maximum values for residual settlement and tilting of the foundations. In order to reveal the influence of soil-building-interaction on the aforementioned response results, the steel building-foundation systems were designed according to Eurocode 8 provisions, assuming initially fixed and then compliant base conditions. It was concluded that for the case of near-fault seismic motions, good seismic performance of steel building-foundation hybrid systems designed according to European Codes was not guaranteed. A particular thing to note for these systems under near-fault seismic motions was that the seismic performance of the steel structure was most likely unacceptable, while one of the foundations was always acceptable.

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