The Zhuanglang river and Baiyin Baiyangshu river faults are late Quaternary faults near Lanzhou city, which pose a threat to the safety of the city. However, the cause of medium- strong earthquakes along the fault is ...The Zhuanglang river and Baiyin Baiyangshu river faults are late Quaternary faults near Lanzhou city, which pose a threat to the safety of the city. However, the cause of medium- strong earthquakes along the fault is rather complicated and even uncertain. It is important for us how to assess the magnitudes of maximum potential earthquakes and the seismic risk of the faults. The authors make reference to the method that Wen Xueze, et ai. （2007） developed to assess the magnitudes of maximum potential earthquakes in sub-areas of moderately and weakly active faults in the eastern Chinese Mainland, and brought forward an empirical relationship between the maximum magnitudes Mmax and the at/b values of the sub-areas＇ frequency- magnitude relationships in the Lanzhou area. By using this empirical relationship, the authors have estimated the upper-limits Mu of the Zhuanglang river and Baiyin Baiyangshu river active faults near Lanzhou city as Ms6.9 and 6.3, respectively. In addition, they have assessed the average interval recurrence time and the probabilities of destructive earthquakes on the faults.展开更多
In recent years the application of friction-based passive energy dissipation devices have been proven very effective in reducing structural response to earthquake excitations and also implemented for a large number of...In recent years the application of friction-based passive energy dissipation devices have been proven very effective in reducing structural response to earthquake excitations and also implemented for a large number of buildings. Their design heavily relies on numerical simulations to model the influence of the energy dissipation devices. The modeling of friction forces must be accurate for realistic simulation of the influence of these devices. In state-of-the-practice, the hysteretic behavior of friction devices has been typically modeled with Coulomb friction having a constant coefficient of friction. However, the basic laws for typical sliding materials and experimental investigations show non-linear relationship between friction and sliding velocity, which includes stiction and Stribeck effect. The influence of stiction and Stribeck effect may be significant and can not be ignored in simulating the dynamic responses of structures with friction-based energy dissipation devices. In this paper the optimal performance of dry friction device in shear-frame buildings when subjected to earthquake ground motions has been investigated. The focus of this paper is on the optimal minimization of response of the shear-frame building. Since buildings with friction devices behave in a highly nonlinear manner, nonlinear response-history analysis considering comprehensive sliding friction models has been carried out. The performance has also been evaluated using the various response measures： the maximum absolute acceleration, the maximum base shear, and the maximum inter-story drift. Different performance indices have been used to quantify the influence of the device properties.展开更多
基金funded by the sub-project of National Science and Technology Support Program(2006BAC13B01-0102)the State Key Project of National 10th Five-year Programentitled"Active fault exploration and seismic risk assessment of Lanzhou city"(Grant No.1-4-28)Contribution No.LZ2008020 for Lanzhou Institute of Seismology,CEA
文摘The Zhuanglang river and Baiyin Baiyangshu river faults are late Quaternary faults near Lanzhou city, which pose a threat to the safety of the city. However, the cause of medium- strong earthquakes along the fault is rather complicated and even uncertain. It is important for us how to assess the magnitudes of maximum potential earthquakes and the seismic risk of the faults. The authors make reference to the method that Wen Xueze, et ai. （2007） developed to assess the magnitudes of maximum potential earthquakes in sub-areas of moderately and weakly active faults in the eastern Chinese Mainland, and brought forward an empirical relationship between the maximum magnitudes Mmax and the at/b values of the sub-areas＇ frequency- magnitude relationships in the Lanzhou area. By using this empirical relationship, the authors have estimated the upper-limits Mu of the Zhuanglang river and Baiyin Baiyangshu river active faults near Lanzhou city as Ms6.9 and 6.3, respectively. In addition, they have assessed the average interval recurrence time and the probabilities of destructive earthquakes on the faults.
文摘In recent years the application of friction-based passive energy dissipation devices have been proven very effective in reducing structural response to earthquake excitations and also implemented for a large number of buildings. Their design heavily relies on numerical simulations to model the influence of the energy dissipation devices. The modeling of friction forces must be accurate for realistic simulation of the influence of these devices. In state-of-the-practice, the hysteretic behavior of friction devices has been typically modeled with Coulomb friction having a constant coefficient of friction. However, the basic laws for typical sliding materials and experimental investigations show non-linear relationship between friction and sliding velocity, which includes stiction and Stribeck effect. The influence of stiction and Stribeck effect may be significant and can not be ignored in simulating the dynamic responses of structures with friction-based energy dissipation devices. In this paper the optimal performance of dry friction device in shear-frame buildings when subjected to earthquake ground motions has been investigated. The focus of this paper is on the optimal minimization of response of the shear-frame building. Since buildings with friction devices behave in a highly nonlinear manner, nonlinear response-history analysis considering comprehensive sliding friction models has been carried out. The performance has also been evaluated using the various response measures： the maximum absolute acceleration, the maximum base shear, and the maximum inter-story drift. Different performance indices have been used to quantify the influence of the device properties.
