An improved planar wavefront model to estimate rocking seismic motion spectra using translational spectra at a single station

2021 ◽  
Vol 144 ◽  
pp. 106612
Author(s):  
Varun K. Singla ◽  
Vinay K. Gupta
2021 ◽  
Vol 11 (4) ◽  
pp. 1551
Author(s):  
Shiping Ge ◽  
Weifeng Wu ◽  
Wenqi Ding ◽  
Yong Yuan

Interchange is essential in a metro network. Regarding the seismic performance, a series of large-scale shaking table tests were performed on an interchange station. The interchange station was composed of a two-story section rigidly connected to a perpendicular three-story section, leading to an abrupt change of stiffness in the conjunction area. Synthetic model soil (a mixture of sand and sawdust) and granular concrete with galvanized steel wires were used to model the soil–structure system. The seismic motion was input along the transversal direction of the two-story structure, including white noise and sinusoidal seismic excitations. Parallel tests of a single two-story station were correspondingly carried out as a contrast. Test data recorded by accelerometers and strain gauges are presented. The bending strains of the columns measured in the interchange station were found to be smaller than those in the single station. The concentration of the longitudinal strain was observed near the conjunction. Insights on the seismic response of the interchange station are provided.


2018 ◽  
Vol 21 (13) ◽  
pp. 1307-1321
Author(s):  
Mahdia Yasmina Mehiaoui ◽  
M. Hadid ◽  
M. K. Berrah
Keyword(s):  

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1178
Author(s):  
Bo Sun ◽  
Bo Tan ◽  
Wenbo Wang ◽  
Elena Simona Lohan

The 5G network is considered as the essential underpinning infrastructure of manned and unmanned autonomous machines, such as drones and vehicles. Besides aiming to achieve reliable and low-latency wireless connectivity, positioning is another function provided by the 5G network to support the autonomous machines as the coexistence with the Global Navigation Satellite System (GNSS) is typically supported on smart 5G devices. This paper is a pilot study of using 5G uplink physical layer channel sounding reference signals (SRSs) for 3D user equipment (UE) positioning. The 3D positioning capability is backed by the uniform rectangular array (URA) on the base station and by the multiple subcarrier nature of the SRS. In this work, the subspace-based joint angle-time estimation and statistics-based expectation-maximization (EM) algorithms are investigated with the 3D signal manifold to prove the feasibility of using SRSs for 3D positioning. The positioning performance of both algorithms is evaluated by estimation of the root mean squared error (RMSE) versus the varying signal-to-noise-ratio (SNR), the bandwidth, the antenna array configuration, and multipath scenarios. The simulation results show that the uplink SRS works well for 3D UE positioning with a single base station, by providing a flexible resolution and accuracy for diverse application scenarios with the support of the phased array and signal estimation algorithms at the base station.


2021 ◽  
Vol 49 (2) ◽  
pp. 212-217
Author(s):  
Katsunobu Sasanuma ◽  
Alan Scheller-Wolf

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Xiuyan Hu ◽  
Qingjun Chen ◽  
Dagen Weng ◽  
Ruifu Zhang ◽  
Xiaosong Ren

In the design of damped structures, the additional equivalent damping ratio (EDR) is an important factor in the evaluation of the energy dissipation effect. However, previous additional EDR estimation methods are complicated and not easy to be applied in practical engineering. Therefore, in this study, a method based on energy dissipation is developed to simplify the estimation of the additional EDR. First, an energy governing equation is established to calculate the structural energy dissipation. By means of dynamic analysis, the ratio of the energy consumed by dampers to that consumed by structural inherent damping is obtained under external excitation. Because the energy dissipation capacity of the installed dampers is reflected by the additional EDR, the abovementioned ratio can be used to estimate the additional EDR of the damped structure. Energy dissipation varies with time, which indicates that the ratio is related to the duration of ground motion. Hence, the energy dissipation during the most intensive period in the entire seismic motion duration is used to calculate the additional EDR. Accordingly, the procedure of the proposed method is presented. The feasibility of this method is verified by using a single-degree-of-freedom system. Then, a benchmark structure with dampers is adopted to illustrate the usefulness of this method in practical engineering applications. In conclusion, the proposed method is not only explicit in the theoretical concept and convenient in application but also reflects the time-varying characteristic of additional EDR, which possesses the value in practical engineering.


2009 ◽  
Vol 1193 ◽  
Author(s):  
Taishi Oouchi ◽  
Hiroyuki Tsuchi ◽  
Tetsuya Ota ◽  
Koji Hane ◽  
Toru Sasaki

AbstractAccording to recent seismic observation records, there are some cases where unexpectedly large seismic motion was observed deep underground and that was larger than at the surface. The factors influencing such phenomena are assumed to be deep geological structures with topographic irregularity, velocity structure and non-linearity of subsurface layers. These factors should be taken into account in the earthquake-resistant design of a geological repository. The influence of a deep underground geological structure with topographic irregularity on ground motion has been studied and it has been confirmed that such a structure have a significant impact on ground motion and the constructive interference of waves may result in strong earthquake ground motion in the vicinity of a structural boundary deep underground.


2016 ◽  
Vol 15 (6) ◽  
pp. 2349-2366 ◽  
Author(s):  
M. Massa ◽  
C. Mascandola ◽  
C. Ladina ◽  
S. Lovati ◽  
S. Barani

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