Structural Response to Complex Synthetic Ground Motions

2009 ◽  
pp. 209-223
Author(s):  
George D. Manolis ◽  
Asimina M. Athanatopoulou
Keyword(s):  
Ground Motions ◽  
Structural Response

Simulating and analyzing artificial nonstationary earthquake ground motions

1982 ◽  
Vol 72 (2) ◽  
pp. 615-636
Author(s):  
Robert F. Nau ◽  
Robert M. Oliver ◽  
Karl S. Pister
Keyword(s):  
Difference Equations ◽  
Kalman Filters ◽  
Ground Motions ◽  
Structural Response ◽  
Model Parameters ◽  
Time Varying ◽  
Nonparametric Method ◽  
Linear Difference Equations ◽  
Earthquake Ground Motions ◽  
Earthquake Accelerograms

Abstract This paper describes models used to simulate earthquake accelerograms and analyses of these artificial accelerogram records for use in structural response studies. The artificial accelerogram records are generated by a class of linear linear difference equations which have been previously identified as suitable for describing ground motions. The major contributions of the paper are the use of Kalman filters for estimating time-varying model parameters, and the development of an effective nonparametric method for estimating the variance envelopes of the accelerogram records.

scholarly journals Non-Gaussian Stochastic Equivalent Linearization Method for Inelastic Nonlinear Systems with Softening Behaviour, under Seismic Ground Motions

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
Francisco L. Silva-González ◽  
Sonia E. Ruiz ◽  
Alejandro Rodríguez-Castellanos
Keyword(s):  
Monte Carlo ◽  
Ground Motions ◽  
Joint Probability ◽  
Structural Response ◽  
Linearization Method ◽  
Degree Of Freedom ◽  
Structural Behavior ◽  
Equivalent Linearization ◽  
Equivalent Linearization Method ◽  
Non Gaussian

A non-Gaussian stochastic equivalent linearization (NSEL) method for estimating the non-Gaussian response of inelastic non-linear structural systems subjected to seismic ground motions represented as nonstationary random processes is presented. Based on a model that represents the time evolution of the joint probability density function (PDF) of the structural response, mathematical expressions of equivalent linearization coefficients are derived. The displacement and velocity are assumed jointly Gaussian and the marginal PDF of the hysteretic component of the displacement is modeled by a mixed PDF which is Gaussian when the structural behavior is linear and turns into a bimodal PDF when the structural behavior is hysteretic. The proposed NSEL method is applied to calculate the response of hysteretic single-degree-of-freedom systems with different vibration periods and different design displacement ductility values. The results corresponding to the proposed method are compared with those calculated by means of Monte Carlo simulation, as well as by a Gaussian equivalent linearization method. It is verified that the NSEL approach proposed herein leads to maximum structural response standard deviations similar to those obtained with Monte Carlo technique. In addition, a brief discussion about the extension of the method to muti-degree-of-freedom systems is presented.

Pounding between Inelastic Three-Storey Buildings under Seismic Excitations

2015 ◽  
Vol 665 ◽  
pp. 121-124 ◽  
Author(s):  
Robert Jankowski
Keyword(s):  
Numerical Analysis ◽  
Numerical Models ◽  
Ground Motions ◽  
Permanent Deformation ◽  
Structural Response ◽  
The Other ◽  
Lumped Mass ◽  
Seismic Excitations ◽  
Structural Interactions ◽  
Inelastic Behaviour

Structural interactions between adjacent, insufficiently separated buildings have been repeatedly observed during damaging ground motions. This phenomenon, known as the structural pounding, may result in substantial damage or even total collapse of structures. The aim of the present paper is to show the results of the nonlinear numerical analysis focused on pounding between inelastic three-storey buildings under seismic excitations. The discrete lumped-mass numerical models of two building have been used in the analysis. The results of the study indicate that the response of the lighter and more flexible inelastic building can be substantially influenced by structural interactions, and collisions may even lead to the permanent deformation of the structure. On the other hand, the behaviour of the heavier and stiffer building does not really change considerably during the earthquake. The results of the study also indicate that incorporation of the inelastic behaviour of colliding buildings with different dynamic characteristics is very important for the purposes of accurate numerical modelling of pounding-involved structural response under damaging seismic excitations.

Drift Spectrum vs. Modal Analysis of Structural Response to Near-Fault Ground Motions

2001 ◽  
Vol 17 (2) ◽  
pp. 221-234 ◽  
Author(s):  
Anil K. Chopra ◽  
Chatpan Chintanapakdee
Keyword(s):  
Earthquake Engineering ◽  
Response Spectrum ◽  
Ground Motions ◽  
Structural Response ◽  
Response Spectra ◽  
Engineering Practice ◽  
Drift Spectrum ◽  
Combination Rules ◽  
Near Fault ◽  
Far Fault

A new measure of earthquake demand, the drift spectrum has been developed as an adjunct to the response spectrum, a central concept in earthquake engineering, in calculating the internal deformations of a structure due to near-fault ground motions with pronounced coherent pulses in the velocity and displacement histories. Compared in this paper are certain aspects of the elastic structural response to near-fault and far-fault ground motions. It is demonstrated that (1) the difference between drift and response spectra are not unique to near-fault ground motions; these differences simply reflect higher-mode response, which is larger due to near-fault ground motions; (2) response spectrum analysis (RSA) using existing modal combination rules can provide an estimate of structural response that is accurate to a useful degree; (3) these modal combination rules are similarly accurate for near-fault and far-fault ground motions although the underlying assumptions are not satisfied by near-fault excitations; and (4) RSA is preferable over the drift spectrum in computing structural response because it represents standard engineering practice and is applicable to a wide variety of structures.

Seismic Reliability analysis of Cable-Stayed Bridges Subjected to Spatially Varying Ground Motions

2021 ◽  
pp. 2150094
Author(s):  
Jin Zhang ◽  
Ke-Jian Chen ◽  
Yong-Ping Zeng ◽  
Zhen-Yu Yang ◽  
Shi-Xiong Zheng ◽  
...  
Keyword(s):  
Reliability Analysis ◽  
Failure Probability ◽  
Maximum Entropy Method ◽  
Ground Motions ◽  
Structural Response ◽  
Entropy Method ◽  
Seismic Reliability ◽  
Spatially Varying Ground Motions ◽  
Spatially Varying ◽  
Cable Stayed Bridges

To efficiently and accurately evaluate the seismic system reliability analysis (SSRA) of cable-stayed bridges subjected to spatially varying ground motions, a direct probabilistic framework was developed in this paper. First, the relevant methods for the structural seismic reliability were presented, including the multiplicative dimensional reduction method, maximum entropy method with fractional moments (FMs), and the product of conditional marginals (PCMs). Second, based on the OpenSees platform, the 3D finite element model of the cable-stayed bridge was established, along with the uncertain structural parameters, stochastic ground motions, and failure modes of each structural component under earthquake loading summarized. Third, considering the double uncertainties of the bridge and ground motions, the nonlinear time history analysis was conducted for the bridge under various scenarios. Finally, the nonlinear seismic response and fractional moment of the structural response were obtained. The maximum entropy method with FMswas used to get the probability density function (pdf) of the structural response, together with the failure probability and reliability index of each component. Considering the correlation between components, the PCMs was used to obtain the failure probability of the bridge under earthquake loadings, and some critical conclusions were drawn.

Representation of Bidirectional Ground Motions for Design Spectra in Building Codes

2011 ◽  
Vol 27 (3) ◽  
pp. 927-937 ◽  
Author(s):  
Jonathan P. Stewart ◽  
Norman A. Abrahamson ◽  
Gail M. Atkinson ◽  
Jack W. Baker ◽  
David M. Boore ◽  
...  
Keyword(s):  
Ground Motion ◽  
Dynamic Properties ◽  
Ground Motions ◽  
Geometric Mean ◽  
Structural Response ◽  
Risk Level ◽  
Lower Probability ◽  
Lumped Mass ◽  
Risk Levels ◽  
Design Spectra

The 2009 NEHRP Provisions modified the definition of horizontal ground motion from the geometric mean of spectral accelerations for two components to the peak response of a single lumped mass oscillator regardless of direction. These maximum-direction (MD) ground motions operate under the assumption that the dynamic properties of the structure (e.g., stiffness, strength) are identical in all directions. This assumption may be true for some in-plan symmetric structures, however, the response of most structures is dominated by modes of vibration along specific axes (e.g., longitudinal and transverse axes in a building), and often the dynamic properties (especially stiffness) along those axes are distinct. In order to achieve structural designs consistent with the collapse risk level given in the NEHRP documents, we argue that design spectra should be compatible with expected levels of ground motion along those principal response axes. The use of MD ground motions effectively assumes that the azimuth of maximum ground motion coincides with the directions of principal structural response. Because this is unlikely, design ground motions have lower probability of occurrence than intended, with significant societal costs. We recommend adjustments to make design ground motions compatible with target risk levels.

Investigation on Damage-Involved Structural Response of Colliding Steel Structures during Ground Motions

2016 ◽  
Vol 713 ◽  
pp. 26-29 ◽  
Author(s):  
Barbara Sołtysik ◽  
Tomasz Falborski ◽  
Robert Jankowski
Keyword(s):  
Dynamic Properties ◽  
Ground Motions ◽  
Structural Response ◽  
Steel Structures ◽  
Separation Distance ◽  
Shaking Table ◽  
Engineering Structures ◽  
Positive Role ◽  
Acceleration Time Histories ◽  
Adjacent Structures

Earthquakes are the most unpredictable damaging loads which can affect civil engineering structures. Due to insufficient separation distance between adjacent structures with different dynamic properties, structural collisions may occur during ground motions. Although the research on structural pounding has recently been much advanced, the studies have mainly been conducted for concrete structures. The aim of this paper is to show the results of experimental investigation, focused on dynamic behaviour of closely-separated three models of steel structures which have been subjected to damaging earthquake excitations. The study was performed using three models of steel towers with different dynamic parameters and various distances between the structures. The acceleration time histories of the Kobe and the Northridge earthquakes were applied as the seismic excitation. The unidirectional shaking table, located at the Gdansk University of Technology (Poland), was used in the experimental study. The results have confirmed that collisions may lead to the increase in the structural response, although they may also play a positive role, depending on the size of the separation gap between the structures.

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