Investigation of Damages in RC Frames Under Near Field Earthquakes Using a Damage Index

2016 ◽  
Vol 16 (02) ◽  
pp. 1450094 ◽  
Author(s):  
Seyed Morteza Zinati Yazdi ◽  
Mohammad Taghi Kazemi
Keyword(s):  
Near Field ◽  
Damage Index ◽  
Time History ◽  
General Rule ◽  
Nonlinear Time History Analysis ◽  
Far Field ◽  
Moment Frames ◽  
Moment Frame ◽  
Rc Frames ◽  
Nonlinear Time History

Heavy damages on structures caused by near field earthquakes in recent years has brought serious attention to this problem. An examination of previous records has shown significant differences for near field earthquakes, including a large energy pulse, unlike far field earthquakes. But as a general rule, the effects of near field earthquakes have been ignored in most building codes. The purpose of this paper is to investigate the effect of near field earthquakes on reinforced concrete (RC) moment frames. To achieve this goal, the Erduran damage index, an efficient way to calculate damage, was employed to analyze two 4- and 8-story RC moment frame buildings. The buildings with moderate and high ductility were designed by the strength criteria. Seven pairs of near field and far field earthquakes were scaled and used for dynamic nonlinear time history analysis. Using Erduran’s beam and column damage index, respectively, based on rotation and drift, the results from both near and far field earthquakes were compared. Moreover, for better assessment, 4-story buildings were evaluated from the performance based viewpoint of design. We observe from the results that most of the components of the structures under near field earthquakes sustained severe damages and in some cases even component failure. Components of the structures under near field earthquakes suffered from 30% more of damage, on average, than that under far field earthquakes.

Effect of bidirectional excitation on seismic performance of regular RC frame buildings designed for modern codes

2021 ◽  
pp. 875529302110478
Author(s):  
Payal Gwalani ◽  
Yogendra Singh ◽  
Humberto Varum
Keyword(s):  
Seismic Performance ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Inelastic Behavior ◽  
Moment Frame ◽  
Frame Buildings ◽  
Bidirectional Excitation ◽  
Rc Frame Buildings ◽  
Nonlinear Time History ◽  
Hinge Model

The existing practice to estimate seismic performance of a regular building is to carry out nonlinear time history analysis using two-dimensional models subjected to unidirectional excitations, even though the multiple components of ground motion can affect the seismic response, significantly. During seismic shaking, columns are invariably subjected to bending in two orthogonal vertical planes, which leads to a complex interaction of axial force with the biaxial bending moments. This article compares the seismic performance of regular and symmetric RC moment frame buildings for unidirectional and bidirectional ground motions. The buildings are designed and detailed according to the Indian codes, which are at par with the other modern seismic codes. A fiber-hinge model, duly calibrated with the biaxial experimental results, is utilized to simulate the inelastic behavior of columns under bidirectional bending. A comparison of the estimated seismic collapse capacity is presented, illustrating the importance of considering the bidirectional effects. The results from fragility analysis indicate that the failure probabilities of buildings under the bidirectional excitation are significantly higher as compared to those obtained under the unidirectional excitation.

scholarly journals Investigating the Performance of Viscoelastic Dampers (VED) Under Nearfield Earthquakes with Directivity Feature

2018 ◽  
Vol 14 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Ali Vatanshenas ◽  
Mohammad Sadegh Rohanimanesh ◽  
Ehsan Mohammadiha
Keyword(s):  
Short Distance ◽  
Near Field ◽  
Time History ◽  
Steel Structure ◽  
Nonlinear Time History Analysis ◽  
Acceleration Response ◽  
Viscoelastic Dampers ◽  
Acceleration Time History ◽  
History Analysis ◽  
Nonlinear Time History

AbstractOne of the most important factors that make structures vulnerable to earthquakes is the short distance between structures and epicenter. Near-field earthquakes have special properties, such as increasing acceleration applied to the structure, which distinguishes them from far-field earthquakes. Therefore, the absorption of input energy for structures located near the faults is very important. Hence, by rotating the earthquake acceleration time history and comparing the resulting spectral acceleration response, the angle which applies the greatest force to the structure on the earthquake directivity side is obtained, and then the performance of a steel structure with viscoelastic dampers (VED) under near-field earthquakes with directivity feature is investigated. After analyzing the structure using nonlinear time history analysis, it was observed that the directivity phenomenon leads to significant increase in the force applied to the structure, but the viscoelastic dampers showed an acceptable performance in both states of with and without directivity.

scholarly journals Seismic assessment of tall RC frames with hybrid friction damper and SMA designed by PBPD method

2021 ◽  
Vol 37 (1) ◽  
Author(s):  
F. Norouzi ◽  
H. Nasebaradi ◽  
M. Jamshidi
Keyword(s):  
Design Method ◽  
Time History ◽  
Hysteretic Behavior ◽  
Nonlinear Time History Analysis ◽  
Friction Damper ◽  
High Rise ◽  
Rc Frames ◽  
Lateral Strength ◽  
Residual Deformations ◽  
Nonlinear Time History

In this study, a new lateral load resisting system for high-rise (Reinforced Concrete) RC frames is proposed, which includes friction damper-superelastic SMA wires. The proposed SMA-friction damper can not only regulate the mechanism of frictional energy dissipation components with its self-centering SMA wires according to the design method based on the proposed performance, which is able to provide a hysteretic behavior and high self-centering capacity with the lowest SMA consumption but also has some advantages such as simple configuration and economic application. In this paper, two high-rise 18 and 22-story RC frames were designed in two design modes of common and with the proposed damper. The nonlinear time history analysis subjected to 10 far-field earthquakes performed in Opensees software. The results of the analyses showed that using the proposed SMA-friction damper, in addition to the effective increase in ductility, lateral stiffness and lateral strength, provided an excellent self-centering capacity, which resulted to the significant reduction in the maximum drift and the residual deformations in the structure.

scholarly journals Seismic Response of Steel SMFs Subjected to Vertical Components of Far- and Near-Field Earthquakes with Forward Directivity Effects

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Shahrokh Shahbazi ◽  
Iman Mansouri ◽  
Jong Wan Hu ◽  
Noura Sam Daliri ◽  
Armin Karami
Keyword(s):  
Near Field ◽  
Vertical Component ◽  
Time History ◽  
Far Field ◽  
Moment Frames ◽  
Maximum Displacement ◽  
Panel Zone ◽  
Forward Directivity ◽  
Directivity Effects ◽  
The Impact

In the near-field earthquake, forward directivity effects cause long-period pulse with a short effective time and a large domain in the velocity time history. This issue increases the ductility needs of structures, and in recent decades, the destructive effects of these kinds of records have been evaluated in comparison with far-field earthquakes. This brings about the necessity to compare a structure’s behavior subjected to vertical components of near-field (NF) earthquakes, including forward directivity effects vs. the effects of vertical components of far-field (FF) earthquakes. The present study investigated 3-, 5-, 8-, and 20-story steel moment frames with special ductility (SMF) through which modeling effects of panel zone have been applied, subjected to vertical component of near-field (NF) earthquakes with forward directivity and the vertical component of far-field earthquakes. By investigating the results, it can be clearly seen that the average values of the maximum displacement, shear force of the stories, and the velocity of each story under the impact of the near-field earthquake are greater than the amount of that under the effect of a far-field earthquake. However, this comparison is not valid for the amount of acceleration, axial force, and moments in the columns of the structures accurately.

scholarly journals Effect of the viscous damping on the seismic response of Low-rise RC frame building

2020 ◽  
pp. 32-43
Author(s):  
Fatima Zohra Baba-Hamed ◽  
Luc Davenne
Keyword(s):  
Reinforced Concrete ◽  
Damage Index ◽  
Time History ◽  
Time History Analysis ◽  
Nonlinear Time History Analysis ◽  
Viscous Damping ◽  
Rc Frame ◽  
History Analysis ◽  
Mdof Systems ◽  
Nonlinear Time History

The equivalent viscous damping is a key parameter in the prediction of the maximum nonlinear response. Damping constitutes a major source of uncertainty in dynamic analysis. This paper studies the effect of using viscous damping, on the reduction of the seismic responses of reinforced concrete RC frame buildings modeled as three-dimensional multi degree of freedom (MDOF) systems, and the use of nonlinear time history analysis as a method of visualized behavior of buildings in the elastic and inelastic range. This study focuses on the implications of the available modeling options on analysis. This article illustrates the effect of using the initial or tangent stiffness in Rayleigh damping in analysis of structures.  Correspondingly, this work is also concerned with the estimation of Rayleigh, mass-proportional or stiffness-proportional damping on engineering demand parameters (EDPs). As a result of a series of considerations, a damping modeling solution for nonlinear time history analysis (NLTHA) was carried out to compute the damage index. The application example is a building designed according to reinforced concrete code BAEL 91 and Algerian seismic code RPA 99/Version 2003 under seven earthquake excitations. The simulations demonstrated the accuracy and effectiveness of the proposed method to account for all of the above effects.

scholarly journals Seismic Response of Steel Moment Frames (SMFs) Considering Simultaneous Excitations of Vertical and Horizontal Components, Including Fling-Step Ground Motions

2019 ◽  
Vol 9 (10) ◽  
pp. 2079 ◽  
Author(s):  
Shahrokh Shahbazi ◽  
Armin Karami ◽  
Jong Wan Hu ◽  
Iman Mansouri
Keyword(s):  
Earthquake Engineering ◽  
Near Field ◽  
Time History ◽  
Horizontal Displacement ◽  
Nonlinear Time History Analysis ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Engineering Structures ◽  
Simultaneous Excitation ◽  
Fling Step

Near-field (NF) earthquakes have drawn considerable attention from earthquake and structural engineers. In the field of earthquake engineering, numerous studies have identified the devastating nature of such earthquakes, and examined the characteristics related to the response of engineering structures to these types of earthquakes. Herein, special steel moment frames (SMFs) of three-, five-, and eight-story buildings have been examined via a nonlinear time history analysis in OpenSees software. The behavioral seismic differences of these frames have been evaluated in two states: (1) under the simultaneous excitation of the horizontal and vertical constituents of near-field earthquakes that have Fling-steps in their records; and (2) under simultaneous excitation of the horizontal and vertical constituents of far-field (FF) earthquakes. In addition, during modeling, the effects of panel zones have been considered. Considering that the simultaneous effects of the horizontal and vertical constituents of near-field earthquakes were subjected to a fling-step resulting in an increased inter-story drift ratio, the horizontal displacement of stories, an axial force of columns, created the moment in columns, base shearing of the structure, and velocity and acceleration of the stories.

Cyclic Pushover Method for Seismic Assessment under Multiple Earthquakes

2019 ◽  
Vol 35 (4) ◽  
pp. 1541-1558
Author(s):  
Alexander Kagermanov ◽  
Robin Gee
Keyword(s):  
Pushover Analysis ◽  
Central Italy ◽  
Time History ◽  
Degree Of Freedom ◽  
Nonlinear Time History Analysis ◽  
Seismic Performance Assessment ◽  
Practical Applications ◽  
Rc Frames ◽  
Cyclic Degradation ◽  
Nonlinear Time History

A new method for the seismic performance assessment of structures subjected to a sequence of earthquakes is presented. The method is based on the cyclic pushover analysis of a multi-degree-of-freedom (MDOF) structure. Instead of relying on a single value of target displacement, as in the case of monotonic push-over methods, a simplified cyclic displacement history is derived from an equivalent single-degree-of-freedom (SDOF) structure for the assessment of the MDOF one. The main advantage of the method is that it directly accounts for cyclic degradation of the actual MDOF system while retaining the simplicity and computational efficiency of SDOF systems for displacement demand evaluation, thus making it attractive for practical applications. The procedure is exemplified in detail using ductile and nonductile reinforced concrete (RC) frames as benchmark structures subjected to the Central Italy sequence. Further comparison with fully nonlinear time-history analysis and code-prescribed monotonic pushover is provided in order to assess the accuracy and advantages of the proposed method.

scholarly journals Seismic Performance of a Green Roof Structure

2021 ◽  
Vol 13 (8) ◽  
pp. 4278
Author(s):  
Svetlana Tam ◽  
Jenna Wong
Keyword(s):  
Green Roof ◽  
Time History ◽  
Green Roofs ◽  
Moment Frame ◽  
Steel Moment Frame ◽  
Roof Structure ◽  
Nonlinear Time History Analyses ◽  
Vegetated Roofs ◽  
Nonlinear Time History ◽  
The Impact

Sustainability addresses the need to reduce the structure’s impact on the environment but does not reduce the environment’s impact on the structure. To explore this relationship, this study focuses on quantifying the impact of green roofs or vegetated roofs on seismic responses such as story displacements, interstory drifts, and floor level accelerations. Using an archetype three-story steel moment frame, nonlinear time history analyses are conducted in OpenSees for a shallow and deep green roof using a suite of ground motions from various distances from the fault to identify key trends and sensitivities in response.

Seismic Behavior of Curved Bridge in Mountain Area

2019 ◽  
Author(s):  
Shuichi Fujikura ◽  
Yuji Sakakibara ◽  
Minh Hai Nguyen ◽  
Akinori Nakajima
Keyword(s):  
Seismic Behavior ◽  
Near Field ◽  
Time History ◽  
Longitudinal Direction ◽  
Mountain Area ◽  
Curved Bridge ◽  
Horizontally Curved ◽  
The 2016 Kumamoto Earthquake ◽  
Post Impact ◽  
Nonlinear Time History

<p>The 2016 Kumamoto Earthquake occurred in central Kyushu, Japan, on April 14th with Mw 6.2 followed by the Mw 7.0 mainshock on April 16th. These earthquakes were mainly caused by the Futagawa fault and Hinagu fault where surface ruptures extended about 34 km long. Some of the bridges located in mountain area and close to the fault were damaged due to these near‐field earthquakes. Oginosaka Bridge is one of them and is a horizontally curved bridge with longitudinal and transverse slope, which is a feature of the bridges located in mountain area. The superstructure was rotated on plan and displaced transversely at both abutments to the opposite side, and there was an evidence of the deck‐abutment pounding in longitudinal direction. In order to investigate the seismic behavior of the curved bridge, nonlinear time‐history analyses including a deck‐abutment pounding interaction were carried out. The deck‐abutment pounding interaction considered in the analyses could capture the post‐impact response of the superstructure. The near‐field ground motions were used for the analyses. The analytical results showed that the curved bridge is susceptible to the deck rotation caused by pounding in longitudinal direction at the deck end under earthquake loading.</p>

scholarly journals Effect of Soil Classification on Seismic Behavior of SMFs considering Soil-Structure Interaction and Near-Field Earthquakes

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Shahrokh Shahbazi ◽  
Iman Mansouri ◽  
Jong Wan Hu ◽  
Armin Karami
Keyword(s):  
Soil Structure ◽  
Near Field ◽  
Free Field ◽  
Soil Structure Interaction ◽  
Nonlinear Time History Analysis ◽  
Type Ii ◽  
Steel Buildings ◽  
Moment Frames ◽  
Structure Interaction ◽  
Soil Flexibility

Seismic response of a structure is affected by its dynamic properties and soil flexibility does not have an impact on it when the bottom soil of foundation is supposedly frigid, and the soil flexibility is also ignored. Hence, utilizing the results obtained through fixed-base buildings can lead to having an insecure design. Being close to the source of an earthquake production causes the majority of earthquake’s energy to reach the structure as a long-period pulse. Therefore, near-field earthquakes produce many seismic needs so that they force the structure to dissipate output energy by relatively large displacements. Hence, in this paper, the seismic response of 5- and 8-story steel buildings equipped with special moment frames (SMFs) which have been designed based on type-II and III soils (according to the seismic code of Iran-Standard 2800) has been studied. The effects of soil-structure interaction and modeling of the panel zone were considered in all of the two structures. In order to model radiation damping and prevent the reflection of outward propagating dilatational and shear waves back into the model, the vertical and horizontal Lysmer–Kuhlemeyer dashpots as seen in the figures are adopted in the free-field boundary of soil. The selected near- and far-field records were used in the nonlinear time-history analysis, and structure response was compared in both states. The results obtained from the analysis showed that the values for the shear force, displacement, column axial force, and column moment force on type-III soil are greater than the corresponding values on type-II soil; however, it cannot be discussed for drift in general.

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