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.

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.

Nonlinear Structural Damage Detection Based on Adaptive Volterra Filter Model

2018 ◽  
Vol 18 (02) ◽  
pp. 1871003 ◽  
Author(s):  
J. Prawin ◽  
A. Rama Mohan Rao
Keyword(s):  
Damage Detection ◽  
Structural Damage ◽  
Linear Models ◽  
Time History ◽  
Diagnostic Techniques ◽  
Filter Model ◽  
Volterra Filter ◽  
Damage Indices ◽  
Before And After ◽  
Nonlinear Time History

The majority of the existing damage diagnostic techniques are based on linear models. Changes in the state of the dynamics of these models, before and after damage in the structure based on the vibration measurements, are popularly used as damage indicators. However, the system may initially behave linearly and subsequently exhibit nonlinearity due to the incipience of damage. Breathing cracks that exhibit bilinear behavior are one such example of the damage induced due to nonlinearity. Further many real world structures even in their undamaged state are nonlinear. Hence, in this paper, we present a nonlinear damage detection technique based on the adaptive Volterra filter using the nonlinear time history response. Three damage indices based on the adaptive Volterra filter are proposed and their sensitiveness to damage and noise is assessed through two numerically simulated examples. Numerical investigations demonstrate the effectiveness of the adaptive Volterra filter model to detect damage in nonlinear structures even with measurement noise.

scholarly journals Performance of an Existing Reinforced Concrete Building Designed in Accordance to Older Indonesian Seismic Code: A Case Study for a Hotel in Kupang, Indonesia

2018 ◽  
Vol 20 (1) ◽  
pp. 35
Author(s):  
Pamuda Pudjisuryadi ◽  
Benjamin Lumantarna ◽  
Ryan Setiawan ◽  
Christian Handoko
Keyword(s):  
Plastic Hinge ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Seismic Load ◽  
Ground Acceleration ◽  
Seismic Code ◽  
Damage Level ◽  
History Analysis ◽  
Nonlinear Time History ◽  
Seismic Hazard Map

The recent seismic code SNI 1726-2012 is significantly different compared to the older code SNI 1726-2002. The seismic hazard map was significantly changed and the level of maximum considered earthquake was significantly increased. Therefore, buildings designed according to outdated code may not resist the higher demand required by newer code. In this study, seismic performance of Hotel X in Kupang, Indonesia which was designed based on SNI-1726-2002 is investigated. The structure was analyzed using Nonlinear Time History Analysis. The seismic load used was a spectrum consistent ground acceleration generated from El-Centro 18 May 1940 North-South component in accordance to SNI 1726-2012. The results show that Hotel X can resist maximum considered earthquake required by SNI 1726-2012. The maximum drift ratio is 0.81% which is lower than the limit set by FEMA 356-2000 (2%). Plastic hinge damage level is also lower than the allowance in ACMC 2001.

Near-fault seismic monitoring reveals the long-lasting activation of a local fault in the Marmara region controlled by slow slip 

2021 ◽  
Author(s):  
Patricia Martínez-Garzón ◽  
Virginie Durand ◽  
Stephan Bentz ◽  
Taylan Turkmen ◽  
Grzegorz Kwiatek ◽  
...  
Keyword(s):  
Temporal Distribution ◽  
Marmara Region ◽  
Slow Slip ◽  
Fault Rupture ◽  
Aseismic Slip ◽  
Seismic Sequences ◽  
Near Fault ◽  
Aftershock Sequences ◽  
Nw Turkey ◽  
Different Characteristics

<p>Recent laboratory and field observations show that fault seismic and aseismic slip may occur concurrently. Here, we combine microseismicity recordings from a temporary near-fault seismic network (SMARTnet) and borehole strainmeter data from the eastern Marmara region in NW Turkey to track seismic and aseismic deformation around the hypocentral region of a M<sub>W</sub> 4.5 earthquake that occurred in 2018. The strainmeter data show a clear strain signal transient starting at the time of the M<sub>W</sub> 4.5 event and lasting for about 150 days. We study about 1,200 microseismic events following the mainshock within and beyond the mainshock fault rupture. The temporal distribution of the seismicity reveals a strong temporal clustering, including four semi-periodic seismic sequences each containing more than 50 events in two days. Two seismic sequences occurred during the strain transient showing different characteristics compared to two sequences occurring afterwards. Seismicity occurring during the transient displayed typical characteristics driven by aseismic slip, such as the activation of a broader region from the mainshock, and the absence of a clear mainshock in each sequence. Seismic sequences occurring after the transient correspond to typical mainshock-aftershock sequences and activated a region closer to the original M<sub>W</sub> 4.5 mainshock. We suggest post-strain transient seismicity originate from stress redistribution and breaking of remaining asperities. Our observations from a newly installed combined dense seismic and strainmeter network in the eastern Sea of Marmara region allows identifying repeated triggering of aseismic transients within an observation period of three years suggesting these may occur more often than previously thought.</p>

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 AN INVESTIGATION ABOUT EFFECTS OF FLUID-STRUCTURE-SOIL INTERACTION ON RESPONSE MODIFICATION COEFFICIENT OF ELEVATED CONCRETE TANKS

2016 ◽  
Vol 8 (1) ◽  
pp. 1-7
Author(s):  
Mirtaha Hashemi ◽  
Khosrow Bargi
Keyword(s):  
Plastic Hinge ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
History Analysis ◽  
Elevated Tanks ◽  
Recent Earthquakes ◽  
Nonlinear Time History ◽  
Seismic Forces

This paper aims to observe effects of fluid-structure-soil interactions on the response modification coefficient of elevated concrete tanks with frame and shaft supporting systems. Because of weaknesses and failures of elevated tanks that have been reported in recent earthquakes and importance of optimum and resistant design and also better seismic performance of these structures, it is essential to investigate on the response modification coefficient of elevated concrete tanks. In this paper, the response modification coefficient has been evaluated by using the numerical modeling. The method of research is a case study. The models have been subjected to an ensemble of important earthquake ground motions. The effects of soilstructure interactions and fluid-structure interactions on seismic behavior of the elevated concrete tanks have been modeled by the equivalent springs and Housner’s method, respectively. Dynamic response of the elevated tanks has been considered by using the nonlinear time history analysis and the discrete plastic hinge approach. Finally, the effects of fluid-structure-soil interactions on the response modification coefficient of the elevated concrete tanks have been discussed by considering results of the analyses. It has been concluded that the codes may underestimate base seismic forces for some seismic regions and some subsoil classes.

The Effect of the Mainshock–Aftershock on the Estimation of the Separation Gap of Regular and Irregular Adjacent Structures with the Soft Story

2019 ◽  
Vol 14 (02) ◽  
pp. 2050008 ◽  
Author(s):  
Mostafa Khatami ◽  
Mohsen Gerami ◽  
Ali Kheyroddin ◽  
Navid Siahpolo
Keyword(s):  
Empirical Relationship ◽  
Time History ◽  
Seismic Sequence ◽  
Steel Moment Resisting Frames ◽  
Soft Story ◽  
Seismic Sequences ◽  
Adjacent Structures ◽  
Sequence Effects ◽  
A Chain ◽  
Nonlinear Time History

One way for decreasing the effect of pounding is to set the separation gap between two adjacent buildings. On the one hand, earthquakes in earthquake-prone zones often occur as a chain of successive earth movements in the form of foreshock, mainshock and aftershock. On the other hand, the existence of soft story in the lowest story of the structure is the most common type of irregularity in lateral stiffness. This paper investigates the effect of seismic sequences to estimate the separation gap at the highest collision level of two adjacent structures. For this purpose, 335 adjacent combinations of regular and irregular steel moment-resisting frames are evaluated which have a soft story on the first story. Separation gap demand is calculated using dynamic analysis of nonlinear time history under a set of seismic sequences which are a combination of the mainshock and aftershock. Results of the total of analysis done show the seismic sequence effects are significant and should be considered in the process of determining the normal separation gap (here after, NSG). Finally, based on the done studies, an empirical relationship is presented to estimate the seismic sequence effects on separation gap of two regular and irregular adjacent structures.

Plastic Analysis on Buckling Restrained Braced Steel Frame

2013 ◽  
Vol 859 ◽  
pp. 157-162
Author(s):  
Xue Zou ◽  
Jun Zhao ◽  
En He Bao ◽  
Yi Hu Chen
Keyword(s):  
Parametric Analysis ◽  
Main Parameter ◽  
Plastic Hinge ◽  
Time History ◽  
Steel Frame ◽  
Buckling Restrained Brace ◽  
Participation Ratio ◽  
Building Models ◽  
Nonlinear Time History Analyses ◽  
Nonlinear Time History

Six pieces of building models were designed for studying the multilayer buckling restrained braced steel frame in this paper. The main parameter in the study included the frame strength and the level Participation ratio β. Second-order nonlinear time history analyses for models are conducted based on plastic hinge theory. The parametric analysis was performed on story displacement and shear. The results revealed that story bending deformation become more remarkable when the frame strength is increasing from 0.3 to 0.5 or the level Participation ratio β from 30% to 90%, and this situation is more obvious on the upper layer. The share of shear by the buckling restrained brace and the largest story shear ratio get larger in these models as the frame strength and the level Participation ratio β increasing.

Seismic Performance of a Deficient Reinforced Concrete Test Frame with Infill Walls

2011 ◽  
Vol 27 (3) ◽  
pp. 817-834 ◽  
Author(s):  
Efe G. Kurt ◽  
Barış Binici ◽  
Özgür Kurç ◽  
Erdem Canbay ◽  
Akpınar ◽  
...  
Keyword(s):  
Ground Motion ◽  
Time History ◽  
Test Method ◽  
Damage State ◽  
Infill Wall ◽  
Damage States ◽  
Scale Levels ◽  
Observed Damage ◽  
Nonlinear Time History ◽  
Element Removal

A two-story, three-bay RC frame with code incompliant seismic design and detailing is tested using continuous pseudodynamic test method for three scale levels of Düzce ground motion. The ground motion produced minimum, significant, and severe damage states on the test structure. Diagonal cracking of the infill wall, column damage in the form of cover spalling and rebar buckling, and complete disintegration of the infill wall were the important observed damage events for the three scale levels, respectively. Nonlinear time history analyses were able to estimate the story displacement response with reasonable accuracy. The importance of element removal for near collapse damage state is unfolded. Tracing the local engineering demand parameters such as strains and curvature was found to be extremely difficult.

Evaluation of Seismic Behavior on Steel Frames with TSW Semi-Rigid Connections under the Nonlinear Time History Analysis

2012 ◽  
Vol 166-169 ◽  
pp. 2083-2087
Author(s):  
Miaad Najdian ◽  
Mohsen Izadinia
Keyword(s):  
Time History ◽  
High Energy ◽  
Time History Analysis ◽  
Nonlinear Time History Analysis ◽  
Near Fault ◽  
Good Ability ◽  
History Analysis ◽  
Ductile Behavior ◽  
Near Fault Earthquakes ◽  
Nonlinear Time History

Movements of pulse shape and the high energy applied in short duration by the near fault earthquake, causes brittle fracture in rigid connections that during the Northridge 1994 and Kobe 1995 earthquakes was frequently seen. Rigid connections, which are generally welded due to lack of ductility, have low energy absorption capability. On the other hand semi-rigid connections have a ductile behavior and have a good ability to absorb energy. The purpose of this paper is analysis and compares the behaviors of “rigid” and “TSW semi-rigid” connections under the near fault earthquakes with nonlinear time history analysis by perform 3D software.

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