An introduction to seismic isolation

Jiang, Lin; Williams, Fernando

doi:10.1016/0141-0296(95)90022-5

Cited by 6 publications

(6 citation statements)

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“…Existing literature [14][15][16][17][18][19][20][21][22][23] demonstrates that the virtual response PSD can be derived from the virtual force, and then the standard deviation of the response can be obtained. The inertial wheel-rail forces are considered in this paper.…”

Section: Derivation Of Psd Of Wheel-rail Forcesmentioning

confidence: 99%

“…[11][12][13] However, the MCM is simple and can only be used as a verification tool, because thousands of samples are needed, which is very time-consuming. To overcome the above shortcomings and ensure the accuracy of results, the pseudo-excitation method (PEM) was proposed by Lin, 14,15 Zhang and Lin, 16 and Zeng. 17 By using the PEM, Li, 18,19 Yu, 20,21 He, 22 Zhao 23 studied bridge responses under random loads.…”

Section: Introductionmentioning

confidence: 99%

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Research on probability statistics of train running safety indices based on pseudo-excitation method

Zhou

Zhang

Sun

2021

Proceedings of the Institution of Mechanical Engineers, Part F:

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In order to explore the random nature of high-speed railway train operation safety indices, the pseudo-excitation method, extreme value theory, and non-stationary harmonic superposition theory are used in this paper to study the statistics of train operation safety indices. The pseudo-excitation load formulation for track irregularity is obtained by the pseudo-excitation method, and the resulting non-stationary random vibration problem is transformed into a deterministic time history problem. The pseudo-excitation method is used to establish the dynamic equations of motion, and the separation iteration method is used to solve the equations, so as to obtain the power spectral density of the wheel-rail interaction forces. The wheel-rail interaction forces are obtained by using a modulation function and the harmonic superposition method. By fitting an extreme value distribution, the maximum values of the train running safety indices are explored. The proposed numerical approach is validated experimentally using the data from a 24.6 m long simply supported concrete bridge by studying the extreme value distributions of driving safety indices. Additional numerical simulation are conducted for varying train speeds and bridge spans. The results show that the Gumbel distribution can fit the extreme value of driving safety parameters for different speeds and different bridge span lengths. It is observed that the higher the speed, the sharper the extreme value distribution of train running safety indices, and the larger the train running safety index values corresponding to 99.87% confidence level. The corresponding extreme values at the 99.87% confidence level are greater than the maximum value of each time-domain sample.

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Section: Derivation Of Psd Of Wheel-rail Forcesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Research on probability statistics of train running safety indices based on pseudo-excitation method

Zhou

Zhang

Sun

2021

Proceedings of the Institution of Mechanical Engineers, Part F:

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“…In the national standard for seismic design of hydraulic structures of China (GB51247-2018), there are specifc requirements "For the design intensity of the aqueduct of VII degree and VII degree above, thus it is advisable to set up a lead core rubber bearing that meets the bearing capacity requirements between the trough and the pier, shock reduction, and isolation devices such as spherical seismic damping bearings or seismic basin bearings" [4]. Tis shows that it is necessary to objectively understand the mechanism of shock isolation and damping of large aqueducts and scientifcally set up isolation and damping devices to achieve the safe operation of the aqueduct structure system under the action of earthquakes [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

On the Adaptability and Effect of High Damping Rubber Bearings in the Seismic Resistance of Large Aqueducts

Zhang

Sun

et al. 2023

Advances in Materials Science and Engineering

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Being the critical hydraulic structure in the construction of national water diversion projects, the large-scale aqueduct is one of the indispensable buildings in the rational allocation of water resources. Moreover, its safe operation during an earthquake is related to the success of the national water network’s construction. In this paper, HDRBs (high damping rubber bearings) have been used as the seismic isolation device for the large aqueduct, considering the FSI (fluid solid interaction) between the water and the walls of the aqueduct, and the mechanical model of HDRBs has been constructed by the bilinear model. The dynamic responses of the large aqueduct under different ground motion excitations, including different peak ground accelerations (PGAs) and operating conditions, have been calculated using the precise integration method. At the same time, the influence of RB (rubber bearings) and HDRBs, two kinds of bearings, on the seismic response of the large aqueduct is compared and analyzed. The maximum reduction in natural frequency with HRDB is about 72%, compared with the use of RB under different working conditions. When there is substitution of HDRB for RB, the stresses in the concrete at the corresponding positions decrease from 1.87 MPa to about 0.71 MPa. The analysis shows that HDRBs are equipped with well seismic isolation and energy dissipation performance, which can effectively reduce the seismic responses and improve the seismic performance of the large aqueduct. In addition, it shows that HDRBs have well adaptability to different operating conditions, ground motion excitation, and PGA, which can be extended to the constructions of aqueduct projects with high seismic intensity and complex geological conditions.

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“…Although they are based on various mechanical phenomena (i.e., elastic response of soft materials, yielding of metals either in bending or torsion, surface friction, sliding, etc. ), the mechanical behavior of seismic isolators is generally characterized by non-linear behavior [14,15] and, hence, non-linear time history (NLTH) analyses are needed to consistently simulate the response of base-isolated (BI) buildings subjected to seismic excitations [16].…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, enhanced formulations are also available in the literature to describe the distribution in height of lateral forces with the aim to take into account relevant parameters, such as the frequency ratio between BI-and fixed-base structure [41,42], the fundamental period of the superstructure [43], the modal shape of the latter [42], the non-linearity factor [14] of seismic isolators [44,45] or combination of some of the above parameters [46][47][48][49]. Under the mathematical standpoint, the proposed formulations are based on either introducing an exponent to h i in Equation (2) [44,46] or combining Equations (1) and (2) [41,42,48].…”

Section: Introductionmentioning

confidence: 99%

On the Distribution in Height of Base Shear Forces in Linear Static Analysis of Base-Isolated Structures

2020

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Although base isolation is nowadays a well-established seismic-protection technique for both buildings and bridges, and several issues are still open and attract the interest of the research community. Among them, the formulation of computationally efficient and accurate analysis methods is a relevant aspect in structural design of seismic-isolated buildings. In fact, codes and guidelines currently in force in various parts of the world generally include the possibility for designers to utilize linear-elastic analysis methods based on equivalent linearization of the non-linear force-displacement response of isolators. This paper proposes a formula for defining the force distribution in height that should be considered in linear-static analyses to obtain a more accurate approximation of the actual structural response, supposedly simulated by means of non-linear time history analysis. To do that, it summarizes the results of a wide parametric analysis carried out on a batch of structures characterized by three different heights and various properties of base isolators. The reported results highlight that the equivalent static force distribution provided by both Italian and European codes tend to underestimate the actual seismic lateral forces acting on base-isolated buildings, whereas the inverted triangular distribution, proposed in various American codes and standards, is often conservative.

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An introduction to seismic isolation

Cited by 6 publications

References 0 publications

Research on probability statistics of train running safety indices based on pseudo-excitation method

Research on probability statistics of train running safety indices based on pseudo-excitation method

On the Adaptability and Effect of High Damping Rubber Bearings in the Seismic Resistance of Large Aqueducts

On the Distribution in Height of Base Shear Forces in Linear Static Analysis of Base-Isolated Structures

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