Seismic performance design of energy-dissipated structure system based on damage control and time-varying damping ratio

2021 ◽  
Vol 151 ◽  
pp. 106996
Author(s):  
Wang Bao-shun ◽  
Hao-xiang He ◽  
Yan Wei-ming
Keyword(s):  
Seismic Performance ◽  
Damage Control ◽  
Damping Ratio ◽  
Time Varying ◽  
Structure System ◽  
Energy Dissipated

scholarly journals Time-Varying Wind Load Identification Based on Minimum-Variance Unbiased Estimation

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Huili Xue ◽  
Kun Lin ◽  
Yin Luo ◽  
Hongjun Liu
Keyword(s):  
Damping Ratio ◽  
Estimation Method ◽  
Minimum Variance ◽  
Wind Load ◽  
Ar Model ◽  
Unbiased Estimation ◽  
Recursive Identification ◽  
Time Varying ◽  
Building Structures ◽  
Shear Building

A minimum-variance unbiased estimation method is developed to identify the time-varying wind load from measured responses. The formula derivation of recursive identification equations is obtained in state space. The new approach can simultaneously estimate the entire wind load and the unknown structural responses only with limited measurement of structural acceleration response. The fluctuating wind speed process is investigated by the autoregressive (AR) model method in time series analysis. The accuracy and feasibility of the inverse approach are numerically investigated by identifying the wind load on a twenty-story shear building structure. The influences of the number and location of accelerometers are examined and discussed. In order to study the stability of the proposed method, the effects of the errors in crucial factors such as natural frequency and damping ratio are discussed through detailed parametric analysis. It can be found from the identification results that the proposed method can identify the wind load from limited measurement of acceleration responses with good accuracy and stability, indicating that it is an effective approach for estimating wind load on building structures.

scholarly journals Experimental estimation of energy dissipated by multistorey post-tensioned timber framed buildings with anti-seismic dissipative devices

2021 ◽  
Vol 1 (2) ◽  
Keyword(s):  
Seismic Performance ◽  
Environmental Sustainability ◽  
Shaking Table ◽  
Shaking Table Tests ◽  
Braced Frame ◽  
Timber Frame ◽  
Experimental Estimation ◽  
Energy Dissipated ◽  
The University ◽  
Post Tensioned

The need to satisfy high seismic performance of structures and to comply with the latest worldwide policies of environmental sustainability is leading engineers and researchers to higher interest in timber buildings. A post-tensioned timber frame specimen was tested at the structural laboratory of the University of Basilicata in Italy, in three different configurations: i) without dissipation (post-tensioning only-F configuration); ii) with dissipative angles (DF- dissipative rocking configuration) and iii) with dissipative bracing systems (BF - braced frame configuration). The shaking table tests were performed considering a set of spectra-compatible seismic inputs at different seismic intensities. This paper describes the experimental estimation of energy dissipated by multistorey post-tensioned timber prototype frame with different anti-seismic hysteretic dissipative devices used in the DF and BF testing configurations. The main experimental seismic key parameters have also been investigated in all testing configurations.

Seismic performance of viscoelastically damped structures at different ambient temperatures

2020 ◽  
pp. 107754632096693
Author(s):  
Jun Dai ◽  
Zhao-Dong Xu ◽  
Pan-Pan Gai ◽  
Xiao Yan
Keyword(s):  
Ambient Temperature ◽  
Temperature Effect ◽  
Seismic Performance ◽  
Structural Parameters ◽  
Damping Ratio ◽  
Historical Earthquakes ◽  
Seismic Evaluation ◽  
Viscoelastic Damper ◽  
Ambient Temperatures ◽  
Seismic Displacement

Experimental results show that mechanical behaviors of viscoelastic dampers are greatly affected by ambient temperature. Neglecting the ambient temperature effect will lead to an inaccurate seismic evaluation on viscoelastically damped structures. This study investigates the ambient temperature effect on the seismic performance of viscoelastically damped structures. An efficient algorithm is proposed to solve the seismic response of viscoelastically damped structures at different ambient temperatures based on the time–temperature correspondence. Numerical simulations of a ten-story viscoelastically damped steel frame under historical earthquakes are presented to illustrate the ambient temperature effect on the seismic performance. The results show that the natural frequency decreases with the increase in ambient temperature, whereas the damping ratio change with ambient temperature greatly depends on the viscoelastic damper properties. The seismic displacement reduction, in general, decreases with the increase in ambient temperature. The seismic acceleration reduction with ambient temperature is affected by the viscoelastic damper properties, structural parameters, and earthquakes together.

scholarly journals Seismic Material Properties of Reinforced Concrete and Steel Casing Composite Concrete in Elevated Pile-Group Foundation

2015 ◽  
Vol 22 (s1) ◽  
pp. 141-148 ◽  
Author(s):  
Mi Zhou ◽  
Wancheng Yuan ◽  
Yue Zhang
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Damping Ratio ◽  
Pile Group ◽  
Ocean Engineering ◽  
Static Loads ◽  
Equivalent Viscous Damping ◽  
Static Tests ◽  
Equivalent Viscous Damping Ratio ◽  
Positive Effect

Abstract The paper focuses on the material mechanics properties of reinforced concrete and steel casing composite concrete under pseudo-static loads and their application in structure. Although elevated pile-group foundation is widely used in bridge, port and ocean engineering, the seismic performance of this type of foundation still need further study. Four scale-specimens of the elevated pile-group foundation were manufactured by these two kinds of concrete and seismic performance characteristic of each specimen were compared. Meanwhile, the special soil box was designed and built to consider soil-pile-superstructure interaction. According to the test result, the peak strength of strengthening specimens is about 1.77 times of the others and the ultimate displacement is 1.66 times of the RC specimens. Additionally, the dissipated hysteric energy capability of strengthening specimens is more than 2.15 times of the others as the equivalent viscous damping ratio is reduced by 50%. The pinching effect of first two specimens is more obvious than latter two specimens and the hysteretic loops of reinforced specimens are more plumpness. The pseudo-static tests also provided the data to quantitatively assessment the positive effect of steel casing composite concrete in aseismatic design of bridge.

Seismic performance of pile group-structure system in liquefiable and non-liquefiable soil from large-scale shake table tests

2020 ◽  
Vol 138 ◽  
pp. 106299 ◽  
Author(s):  
Chengshun Xu ◽  
Pengfei Dou ◽  
Xiuli Du ◽  
M. Hesham El Naggar ◽  
Masakatsu Miyajima ◽  
...  
Keyword(s):  
Seismic Performance ◽  
Large Scale ◽  
Group Structure ◽  
Pile Group ◽  
Shake Table ◽  
Shake Table Tests ◽  
Structure System ◽  
Liquefiable Soil

scholarly journals Damping Effects Induced by a Mass Moving along a Pendulum

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
E. Gandino ◽  
S. Marchesiello ◽  
A. Bellino ◽  
A. Fasana ◽  
L. Garibaldi
Keyword(s):  
Linear Time ◽  
Damping Ratio ◽  
System Response ◽  
Time Varying ◽  
Simple Method ◽  
Equivalent Damping ◽  
Stochastic Subspace Identification ◽  
Time Varying Systems ◽  
Instantaneous Frequencies ◽  
Short Time

The experimental study of damping in a time-varying inertia pendulum is presented. The system consists of a disk travelling along an oscillating pendulum: large swinging angles are reached, so that its equation of motion is not only time-varying but also nonlinear. Signals are acquired from a rotary sensor, but some remarks are also proposed as regards signals measured by piezoelectric or capacitive accelerometers. Time-varying inertia due to the relative motion of the mass is associated with the Coriolis-type effects appearing in the system, which can reduce and also amplify the oscillations. The analytical model of the pendulum is introduced and an equivalent damping ratio is estimated by applying energy considerations. An accurate model is obtained by updating the viscous damping coefficient in accordance with the experimental data. The system is analysed through the application of a subspace-based technique devoted to the identification of linear time-varying systems: the so-called short-time stochastic subspace identification (ST-SSI). This is a very simple method recently adopted for estimating the instantaneous frequencies of a system. In this paper, the ST-SSI method is demonstrated to be capable of accurately estimating damping ratios, even in the challenging cases when damping may turn to negative due to the Coriolis-type effects, thus causing amplifications of the system response.

scholarly journals Effect of Friction Pendulum Bearing System on Seismic Performance of Structure

2020 ◽  
Vol 9 (4) ◽  
pp. 740-743
Keyword(s):  
Seismic Performance ◽  
Damping Ratio ◽  
Point Of View ◽  
Current Paper ◽  
Design Point ◽  
Probability Of Occurrence ◽  
Time Period ◽  
Friction Pendulum ◽  
Bearing System

The current paper investigates the behavior of friction pendulum bearing. Recently developed Triple friction pendulum bearing exhibits as a adaptive in nature for the different level of earthquakes along with its flexibility in design point of view. Different level of earthquakes based on probability of occurrence are considered earthquakes are considered to understand the behavior of TFP bearings. To achieve the target damping ratio and time period, three different models are designed. The influence of increase in displacement shows more effective results in design bases earthquake.

scholarly journals Theoretical Derivation and Parameters Analysis of a Human-Structure Interaction System with the Bipedal Walking Model

2021 ◽  
Vol 2021 ◽  
pp. 1-28
Author(s):  
Huiqi Liang ◽  
Zhiqiang Zhang ◽  
Peizi Wei
Keyword(s):  
Numerical Simulations ◽  
Damping Ratio ◽  
Bipedal Walking ◽  
Lumped Mass ◽  
Structure System ◽  
Structure Interaction ◽  
Mode Superposition Method ◽  
Interaction System ◽  
Wide Range ◽  
The Continuum

The excessive vertical vibration of structures induced by walking pedestrians has attracted considerable attention in the past decades. The bipedal walking models proposed previously, however, merely focus on the effects generated by legs and ignore the effects of the dynamics of body parts on pedestrian-structure interactions. The contribution of this paper is proposing a novel pedestrian-structure interaction system by introducing the concept of the continuum and a different variable stiffness strategy. The dynamic model of pedestrian-structure coupling system is established using the Lagrange method. The classical mode superposition method is utilized to calculate the response of the structure. The state-space method is employed to determine natural frequencies and damping ratio of the coupled system. Based on the proposed model, numerical simulations and parametric analysis are conducted. Numerical simulations have shown that the continuum enables the pedestrian-structure system to achieve the stable state more efficiently than the classic model does, which idealizes the body as a concentrated or lumped mass. The parametric study reveals that the presence of pedestrians is proved to significantly decrease the frequency of human-structure interaction system and improve its damping ratio. Moreover, the parameters of the bipedal model have a noticeable influence on the dynamic properties and response of the pedestrian-structure system. The bipedal walking model proposed in this paper depicts a pattern of pedestrian-structure interactions with different parameter settings and has a great potential for a wide range of practical applications.

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