Near-fault effects on residual displacements of RC structures

2016 ◽  
Vol 45 (9) ◽  
pp. 1391-1409 ◽  
Author(s):  
Eftychia Liossatou ◽  
Michael N. Fardis
Keyword(s):  
Rc Structures ◽  
Near Fault ◽  
Residual Displacements

Residual displacements of RC structures as SDOF systems

2014 ◽  
Vol 44 (5) ◽  
pp. 713-734 ◽  
Author(s):  
Eftychia Liossatou ◽  
Michael N. Fardis
Keyword(s):  
Rc Structures ◽  
Residual Displacements

scholarly journals FRP Composite in Mitigating Seismic Risk of RC Structures in Near-Fault Regions with/without Aftershocks

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Vui Van Cao ◽  
Son Quang Pham
Keyword(s):  
Plastic Hinge ◽  
Time History ◽  
Damage State ◽  
Rc Structures ◽  
Seismic Sequences ◽  
Near Fault ◽  
Damage Indices ◽  
Aftershock Sequences ◽  
Nonlinear Time History ◽  
Original Frame

The literature related to earthquakes and fibre reinforced polymer (FRP) retrofitting can be divided into two main categories: (1) the applications of FRP to retrofit structures subjected to single traditional earthquakes and (2) the effects of mainshock-aftershock sequences on original structures (without FRP retrofitting). Research on using FRP to mitigate the risk of pulse-type mainshock-aftershock sequences for reinforced concrete (RC) structures located in near-fault regions is hardly found in the literature and is thus the aim of this study. To achieve this aim, a four-storey RC frame, near-fault mainshocks, and seismic sequences were selected. The frame was retrofitted using FRP wraps at plastic hinge locations. Nonlinear time history and damage analyses of the original and FRP-retrofitted frames subjected to these near-fault mainshocks and seismic sequences were conducted. The results showed that aftershocks significantly increase the damage indices of the frames, shifting the damage state of the original frame from severe damage to collapse and the damage state of the FRP-retrofitted frame from light damage to moderate damage. FRP retrofitting successfully reduced the risk of seismic sequences by reducing the damage two levels, shifting the damage state of the original frame from collapse to moderate damage.

Simulating Maximum and Residual Displacements of RC Structures: II. Sensitivity

2011 ◽  
Vol 27 (4) ◽  
pp. 1203-1218 ◽  
Author(s):  
Ufuk Yazgan ◽  
Alessandro Dazio
Keyword(s):  
Damping Ratio ◽  
Time Integration ◽  
Integration Step ◽  
Discretization Scheme ◽  
Hysteretic Model ◽  
Step Size ◽  
Shake Table Tests ◽  
Rc Structures ◽  
Residual Displacements ◽  
Response History Analysis

The simulated response of a structure subjected to seismic excitation is sensitive to the idealizations made to model its response. This paper examines critical idealizations and assumptions that have a strong influence on the accuracy of the maximum and residual displacements predicted by response-history analysis. A set of shake table tests are numerically reproduced for this purpose. The investigated idealizations include the discretization scheme, the axial load, the steel hysteretic model, the viscous damping ratio, and the time-integration step size. The results indicate that the simulated residual displacements are significantly more sensitive to the model idealizations than the maximum displacements. It is found that the adopted discretization scheme and the utilized steel hysteresis model have very large influences on simulated residual displacements.

scholarly journals Seismic Response of the Three-Span Bridge with Innovative Materials Including Fault-Rupture Effect

2018 ◽  
Vol 2018 ◽  
pp. 1-18 ◽  
Author(s):  
Jiping Ge ◽  
M. Saiid Saiidi
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Plastic Hinge ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Ground Displacement ◽  
Finite Element Software ◽  
Near Fault ◽  
Residual Displacements ◽  
Parallel Direction

The seismic performance of the SR99 Bridge with conventional and advanced details in Seattle, Washington, was studied via a nonlinear, time history analysis of a multidegree of freedom model. The bridge consists of three spans supported on two single-column piers and will be the first built bridge in the world in which superelastic shape memory alloy (SMA) and engineered cementitious composite (ECC) are implemented to reduce damage at plastic hinges and minimize residual displacements. Existing finite-element formulations in the finite-element software OpenSees are used to capture the response of the advanced materials used in the bridge. The earthquake induced by strike-slip fault was assumed to produce a surface rupture across the SR99 Bridge. The effect of the rupture was modeled by a static, differential ground displacement in the fault-parallel direction across the rupture. The synthetic suite of scaled bidirectional near-fault ground motions used in the analysis contains common near-fault features including a directivity pulse in the fault-normal direction and a fling step in the fault-parallel direction. Comparisons are made on behavior of two different bridge types. The first is a conventional reinforced concrete bridge and the second is a bridge with Nickel-Titanium (NiTi) SMA reinforcing bar at the plastic hinge zone and ECC in the whole column. Fault-parallel near-fault earthquakes typically exhibit a static permanent ground displacement caused by the relative movement of the two sides of the fault. When the fault is located between piers, the pier shows a higher demand. Fault-normal analysis results show effectiveness of the innovative interventions on the bridges in providing excellent recentering capabilities with minimal damage to the columns. But the maximum drift computed in the SMA bridge is slightly higher than reinforced concrete (RC) bridges, contributed by comparatively low stiffness of the superelastic SMA bars compared to the steel reinforcing bars.

scholarly journals Effect of a Near Fault on the Seismic Response of a Base-Isolated Structure with a Soft Storey

2017 ◽  
Vol 25 (4) ◽  
pp. 34-46
Author(s):  
B. Athamnia ◽  
A. Ounis ◽  
M. Abdeddaim
Keyword(s):  
Seismic Isolation ◽  
Seismic Analysis ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Base Shear ◽  
Rc Structures ◽  
Soft Storey ◽  
Near Fault ◽  
Nonlinear Time History ◽  
Far Fault

AbstractThis study focuses on the soft-storey behavior of RC structures with lead core rubber bearing (LRB) isolation systems under near and far-fault motions. Under near-fault ground motions, seismic isolation devices might perform poorly because of large isolator displacements caused by large velocity and displacement pulses associated with such strong motions. In this study, four different structural models have been designed to study the effect of soft-storey behavior under near-fault and far-fault motions. The seismic analysis for isolated reinforced concrete buildings is carried out using a nonlinear time history analysis method. Inter-story drifts, absolute acceleration, displacement, base shear forces, hysteretic loops and the distribution of plastic hinges are examined as a result of the analysis. These results show that the performance of a base isolated RC structure is more affected by increasing the height of a story under nearfault motion than under far-fault motion.

Simulating Maximum and Residual Displacements of RC Structures: I. Accuracy

2013 ◽  
Vol 29 (2) ◽  
pp. 675-677 ◽  
Author(s):  
Mostafa Tazarv ◽  
M. Saiid Saiidi
Keyword(s):  
Rc Structures ◽  
Residual Displacements

Simulating Maximum and Residual Displacements of RC Structures: I. Accuracy

2011 ◽  
Vol 27 (4) ◽  
pp. 1187-1202 ◽  
Author(s):  
Ufuk Yazgan ◽  
Alessandro Dazio
Keyword(s):  
Companion Paper ◽  
Accurate Estimation ◽  
Model Parameters ◽  
Seismic Performance Assessment ◽  
Shake Table Tests ◽  
Rc Structures ◽  
Flexural Response ◽  
Bilinear Models ◽  
Residual Displacements ◽  
Global And Local

Estimation of likely global and local response measures plays an important role in seismic performance assessment. The capabilities and limitations of beam-column element modeling strategies in predicting the dynamic nonlinear flexural response of RC models are investigated in this study. For this purpose, 12 shake table tests are numerically reproduced. Correlations of the predicted deformations with the measured ones are evaluated. The results show that maximum displacements can be estimated with sufficient accuracy if the adopted hysteresis model takes into account stiffness degradation. However, accurate estimation of the residual displacements is found to be difficult to achieve. The results suggest that the assumed small-cycle behavior has a strong influence on the estimated residual displacements. Fiber-section models are found to provide relatively more accurate estimates of the residual displacements than modified Takeda hysteretic and bilinear models. A companion paper, Part II: Sensitivity, presents the sensitivity of the simulated displacements to a set of the model parameters and idealizations.

Residual displacement estimation of the bilinear SDOF systems under the near-fault ground motions using the BP neural network

2021 ◽  
pp. 136943322110585
Author(s):  
Mingkang Wei ◽  
Xiaobin Hu ◽  
Huanxin Yuan
Keyword(s):  
Neural Network ◽  
Bp Neural Network ◽  
Structural Parameters ◽  
Ground Motions ◽  
Calculated Data ◽  
Time History ◽  
Strength Reduction Factor ◽  
Residual Displacement ◽  
Near Fault ◽  
Residual Displacements

This paper presents a comprehensive study of residual displacements of the bilinear single degree of freedom (SDOF) systems under the near-fault ground motions (NFGMs). Five sets of NFGMs were constructed in this study, in which the natural ones as well as the synthesized ones were both considered. By way of the nonlinear time history analyses, three different residual displacement spectrums were obtained and analyzed in detail. Utilizing the calculated data, a back propagation (BP) neural network was established to predict the residual displacements of the bilinear SDOF systems under the NFGMs. The results show that the structural parameters, including the strength reduction factor and the post-yield strength ratio, have significant and relatively consistent impacts on the residual displacement spectrum. However, the ground motion characteristics, including the fault type, the closest distance from the site to the fault rupture, the earthquake magnitude, and the site soil condition, exhibit more complex effects on the residual displacement spectrum. In addition, the proposed BP neural network can fully incorporate the parameters affecting the residual displacements of the bilinear SDOF systems under the NFGMs, while having a fairly good accuracy in predicting the residual displacements.

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