Constant-ductility energy factors of SDOF systems subjected to mainshock–aftershock sequences

2020 ◽  
pp. 875529302095246
Author(s):  
Duofa Ji ◽  
Weiping Wen ◽  
Changhai Zhai
Keyword(s):  
Relative Intensity ◽  
Damping Ratio ◽  
Soil Condition ◽  
Stiffness Ratio ◽  
Ground Acceleration ◽  
Vibration Period ◽  
Energy Factor ◽  
Energy Factors ◽  
Covered Area ◽  
Aftershock Sequences

This article focuses on the energy factor of single-degree-of-freedom (SDOF) systems subjected to mainshock–aftershock (MSAS) sequences, of which 163 and 143 are collected from crustal and subduction regions, respectively. The recorded MSAS sequences are divided into four groups based on the relative intensity that is defined as the ratio of the peak ground acceleration ( PGA) of an aftershock to the PGA of the corresponding mainshock. Constant-ductility inelastic spectra are calculated to assess the energy factor, γ, defined as the ratio of the covered area of the skeleton load-deformation curve of the inelastic structural system to that of the corresponding elastic system with identical elastic properties, by considering various levels of structural inelasticity. Moreover, the effect of the hysteresis law, damping ratio, post-yield stiffness ratio, soil condition, and relative intensity on the energy factor is thoroughly analyzed. A predictive model is also developed as a function of the ductility factor, vibration period, damping ratio, and post-yield stiffness ratio. Such a model is expected to facilitate the energy-based seismic design of structures.

scholarly journals Constant Ductility Site-Specific Yield Point Spectra for Seismic Design

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Duofa Ji ◽  
Weiping Wen ◽  
Changhai Zhai
Keyword(s):  
Yield Point ◽  
Seismic Design ◽  
Iterative Process ◽  
Design Method ◽  
Damping Ratio ◽  
Prediction Equation ◽  
Specific Yield ◽  
Stiffness Ratio ◽  
Vibration Period ◽  
Strength And Stiffness

Displacement-based seismic design (DBSD) is an iterative process because the strength and stiffness of a structure are needed to be adjusted in order to achieve a specific performance level, which is extremely inconvenient for designers in practice. Yield point spectra-based seismic design is treated as an alternative design method in which yield displacement as a basic parameter will not lead to an iterative process even though the lateral strength or stiffness of a structure changes during the whole design process. Along this line, this study focuses on investigating the yield point spectra (YPS) for structures located at different soil sites. YPS are computed for EPP systems under 601 earthquake ground motions. YPS for four soil sites are quantitatively analyzed by considering the influence of the vibration period, ductility factor, damping ratio, postyield stiffness ratio, and P-delta effect. The results indicate that compared with the effects of the damping ratio, the effects of the postyield stiffness ratio and P-delta effect on YPS are more profound. Finally, a prediction equation is proposed accounting for four soil sites and six ductility factors.

Seismic Performance of T-Shaped CFT Column to Steel Frame Beam Connection – Experimental Study

2014 ◽  
Vol 919-921 ◽  
pp. 951-959 ◽  
Author(s):  
Yan Tao Li ◽  
Cheng Xiang Xu ◽  
Guo Feng Du
Keyword(s):  
Failure Mechanism ◽  
Damping Ratio ◽  
Local Buckling ◽  
Steel Tube ◽  
Steel Frame ◽  
Hysteretic Behavior ◽  
Stiffness Ratio ◽  
Joint Models ◽  
Panel Zone ◽  
Axial Forces

The focus of this research program is T-shaped CFT central column to steel frame beam connection. 3 joints with strong columns-weak beams and 1 joint with strong beams-weak columns 1:2 scale specimens were tested under constant axial loads and cyclic horizontal loads. Overall impact of axial force ratio and beam to column linear stiffness ratio on joint failure mechanism, hysteretic behavior, deformation ductility, and energy dissipation capability was investigated. Results showed that the failure mechanism for specimens with strong columns-weak beams was local buckling of the steel beam flanges and formation of the plastic hinges. There was minimum damage on the concrete column and joint panel zone. For a specimen with strong beams-weak columns, there was local buckling fracture on steel tube above and below the joint panel zone. Crushing of the core concrete was also observed with formation of the column hinges. It was found that both axial forces and beam to column linear stiffness ratio had impacts on joint capacity and ductility behavior of the specimens. Experiment results showed that the joint models had deformation ductility factor between 3.39 and 3.91 and viscous damping ratio between 0.46 and 0.51.

Experimental Study on the Performance of the Laminated Steel Isolators

2013 ◽  
Vol 423-426 ◽  
pp. 1603-1607
Author(s):  
Yao Guo Xie ◽  
Ping He ◽  
Xian Qiang Qu ◽  
Hong Bin Cui
Keyword(s):  
Experimental Study ◽  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Damping Ratio ◽  
Dynamic Performance ◽  
Performance Testing ◽  
Stiffness Ratio ◽  
Static Stiffness ◽  
Comparison Of The Results

Through the analysis and comparison of the results of static and dynamic performance testing of a series of laminated steel pieces isolators used in the vibration isolation of warships, in the number and thickness of laminated steel pieces of the same circumstances, laminated steel arc and preload of test samples had a certain impact on the values ​​of static stiffness, dynamic stiffness, damping ratio as well as dynamic and static stiffness ratio.

scholarly journals Predicting the peak structural displacement preventing pounding of buildings during earthquakes

2021 ◽  
Vol 2070 (1) ◽  
pp. 012010
Author(s):  
S M Khatami ◽  
H Naderpour ◽  
A Mortezaei ◽  
S T. Tafreshi ◽  
A Jakubczyk-Gałczyńska ◽  
...  
Keyword(s):  
Structural Model ◽  
Lateral Displacement ◽  
Critical Distance ◽  
Lumped Mass ◽  
Seismic Excitations ◽  
Ground Acceleration ◽  
Vibration Period ◽  
Adjacent Buildings ◽  
Artificial Neural Network Ann ◽  
Story Building

Abstract The aim of the present paper is to verify the effectiveness of the artificial neural network (ANN) in predicting the peak lateral displacement of multi-story building during earthquakes, based on the peak ground acceleration (PGA) and building parameters. For the purpose of the study, the lumped-mass multi-degree-of-freedom structural model and different earthquake records have been considered. Firstly, values of stories mass and stories stiffness have been selected and building vibration period has been automatically calculated. The ANN algorithm has been used to determine the limitation of the peak lateral displacement of the multi-story building with different properties (height of stories, number of stories, mass of stories, stiffness of stories and building vibration period) exposed to earthquakes with various PGA. Then, the investigation has been focused on critical distance between two adjacent buildings so as to prevent their pounding during earthquakes. The proposed ANN has logically predicted the limitation of the peak lateral displacement for the five-story building with different properties. The results of the study clearly indicate that the algorithm is also capable to properly predict the peak lateral dis-placements for two buildings so as to prevent their pounding under different earthquakes. Subsequently, calculation of critical distance can also be optimized to save the land and provide the safety space between two adjacent buildings prone to seismic excitations.

The Dynamic Characteristics Analysis of Liaocheng Guangyue Tower

2015 ◽  
Vol 744-746 ◽  
pp. 920-923
Author(s):  
Zhao Bo Meng ◽  
Yu Cao ◽  
Jie Jin
Keyword(s):  
Numerical Analysis ◽  
Dynamic Characteristics ◽  
Natural Vibration ◽  
Damping Ratio ◽  
Analysis Method ◽  
Vibration Period ◽  
Incentive Effect ◽  
First Order ◽  
Characteristics Analysis ◽  
Dynamic Characteristics Analysis

Taking Liaocheng Guangyue tower as an example, based on the on-site measurements, to determine its dynamic characteristics and provide a basis by numerical analysis method for determining traffic incentive effect on the ancient timber buildings. From the research, we can conclude that the first-order self-vibration frequency of Guangyue tower can be taken as 1.638Hz, the corresponding natural vibration period is 0.61s,the damping ratio is 1.098.

Empirical Correlations between Generalized Ground-Motion Intensity Measures for Earthquakes in China

2020 ◽  
Author(s):  
Kun Ji ◽  
Yefei Ren ◽  
Ruizhi Wen
Keyword(s):  
Ground Motion ◽  
Correlation Coefficients ◽  
Parametric Models ◽  
Peak Ground Velocity ◽  
Ground Acceleration ◽  
Intensity Measures ◽  
Vibration Period ◽  
Significant Duration ◽  
Cumulative Absolute Velocity ◽  
Spectrum Intensity

ABSTRACT This study used earthquake records from China to investigate comprehensively the correlation coefficients between various intensity measures (IMs), including peak ground acceleration, peak ground velocity, spectral acceleration, spectrum intensity, acceleration spectrum intensity, Arias intensity, cumulative absolute velocity, and significant duration. After collection of metadata information, 681 three-component ground-motion recordings with magnitudes of Mw 4.9–6.9 were carefully processed and extracted from the China National Strong-Motion Observation Network System dataset (2007–2015). The applicability of both the Next Generation Attenuation (NGA)-West2 ground-motion model (GMM) and of other GMMs was verified for different IMs, regarding the China dataset. Then, empirical correlation coefficients between different IMs were computed, considering the uncertainty due to the different sample sizes of the observational data using the bootstrap sampling method and Fisher z transformation. Finally, the median values of the correlation coefficients were fitted as a continuous function of the vibration period in the range of 0.01–10.0 s and compared with the results of similar studies developed for shallow crustal regions worldwide. The developed region-specific correlation coefficient prediction model yielded tendencies approximately like those reported in other studies. However, obvious differences were found in long-period ranges of amplitude-based IMs, cumulative effect IMs, and significant duration. These results suggest the necessity of using region-specific correlation coefficients for generalized IMs in China. The presented results and parametric models could be easily implemented in a generalized IM ground-motion selection method or a vector-based probability seismic hazard analysis procedure for China.

Parameters optimization of dynamic vibration absorber based on grounded stiffness, inerter, and amplifying mechanism

2021 ◽  
pp. 107754632110382
Author(s):  
Peng Sui ◽  
Yongjun Shen ◽  
Shaopu Yang ◽  
Junfeng Wang
Keyword(s):  
Analytical Solution ◽  
Vibration Isolation ◽  
Damping Ratio ◽  
Vibration Absorber ◽  
Primary System ◽  
Vibration Absorbers ◽  
Stiffness Ratio ◽  
Dynamic Vibration Absorber ◽  
Dynamic Vibration ◽  
Dynamic Vibration Absorbers

In the field of dynamics and control, some typical vibration devices, including grounded stiffness, inerter and amplifying mechanism, have good vibration isolation and reduction effects, especially in dynamic vibration absorber (DVA). However, most of the current research studies only focus on the performance of a single device on the system, and those DVAs are gradually becoming difficult to meet the growth of performance demand for vibration control. On the basis of Voigt dynamic vibration absorber, a novel dynamic vibration absorber model based on the combined structure of grounded stiffness, inerter, and amplifying mechanism is presented, and the analytical solution of the optimal design formula is derived. First, the motion differential equation of the system is established, and the normalized amplitude amplification factor of the displacement is calculated. It is found that the system has three fixed points unrelated to the damping ratio. The optimal frequency ratio is obtained based on the fixed-point theory. In order to ensure the stability of the system, it is found that inappropriate inerter coefficient will cause the system instable when screening optimal grounded stiffness ratio. Accordingly, the best working range of inerter is determined. Finally, optimal grounded stiffness ratio and approximate optimal damping ratio are also obtained. The influence of inerter coefficient and magnification ratio on the response of the primary system is analyzed. The correctness of the derived analytical solution is verified by numerical simulation. Compared with other dynamic vibration absorbers, it is verified that presented model has superior vibration absorption performance and provides a theoretical basis for the design of a new type of dynamic vibration absorbers.

A New Type of Hybrid-Passive-Damper

2010 ◽  
Vol 163-167 ◽  
pp. 4367-4372
Author(s):  
Ai Rong Liu ◽  
Qi Cai Yu ◽  
Yuan Yao ◽  
Yu Zhu Guo
Keyword(s):  
Energy Dissipation ◽  
Damping Ratio ◽  
Loading Frequency ◽  
Vibration Period ◽  
Equivalent Damping ◽  
Passive Damper ◽  
New Type ◽  
Energy Dissipation Capacity ◽  
Relationship Of ◽  
The Relationship

This paper investigated the superelasticity and hysteresis characteristics of TiNi shape memory alloy ( SMA ) wire at room temperature, then the mechanical parameters of which were obtained. Based on the TiNi SMA wire and a purchased viscous damper, a new type of hybrid-passive-damper was designed and developed. Experiments were performed in order to validate the relationship of loading frequency and characteristic parameters such as energy dissipation capacity, equivalent damping ratio and equivalent stiffness. Experimental results show that hybrid-passive-damper designed in this paper has excellent energy dissipation capacity and is suitable for the vibration control of structures with long vibration period.

Seismic Hazard Mapping for Italy in Terms of Broadband Displacement Response Spectra

2009 ◽  
Vol 25 (3) ◽  
pp. 515-539 ◽  
Author(s):  
Ezio Faccioli ◽  
Manuela Villani
Keyword(s):  
Seismic Hazard ◽  
Response Spectra ◽  
Elastic Response ◽  
Elastic Displacement ◽  
Hazard Mapping ◽  
Ground Acceleration ◽  
Vibration Period ◽  
Displacement Spectra ◽  
Elastic Response Spectra ◽  
Short Period

A new representation of seismic hazard is proposed for Italy based on displacement elastic response spectra in a vibration period range that extends from [Formula: see text]. This relies on an available seismotectonic zonation and earthquake catalogue, but makes use of a set of very recent, expressly developed attenuation relations. The long period picture of ground motion hazard is illustrated vis-à-vis the conventional one based on ground acceleration, and the feasibility of simple approximations of the displacement spectra, useful for design purposes, is shown. We give some foresight on the differences to be expected in hazard maps resulting from the use of a predominantly fault-based seismic source model, as opposed to the more conventional model that includes only spatially extended zones. Finally, we highlight the different hazard exposure of different regions depending on whether we represent hazard with a long or a short period parameter and we discuss the adequacy of recent code provisions regarding elastic displacement spectra.

Sign in / Sign up

Export Citation Format

Share Document