scholarly journals Seismic Response of Base-Isolated High-Rise Buildings under Fully Nonstationary Excitation

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
C. F. Ma ◽  
Y. H. Zhang ◽  
P. Tan ◽  
F. L. Zhou
Keyword(s):  
Element Model ◽  
Degree Of Freedom ◽  
Dynamic Responses ◽  
Earthquake Ground Motion ◽  
Equivalent Linearization ◽  
Width Ratio ◽  
High Rise ◽  
High Rise Building ◽  
Linearization Methods ◽  
Shear Type

Stochastic seismic responses of base-isolated high-rise buildings subjected to fully nonstationary earthquake ground motion are computed by combining the pseudoexcitation and the equivalent linearization methods, and the accuracy of results obtained by the pseudoexcitation method is verified by the Monte Carlo method. The superstructure of a base-isolated high-rise building is represented by a finite element model and a shear-type multi-degree of freedom model, respectively. The influence of the model type and the number of the modes of the superstructure participating in the computation of the dynamic responses of the isolated system has been investigated. The results of a 20-storey, 3D-frame with height to width ratio of 4 show that storey drifts and absolute accelerations of the superstructure for such a high-rise building will be substantially underestimated if the shear-type multi-degree of freedom model is employed or the higher modes of the superstructure are neglected; however, this has nearly no influence on the drift of the base slab.

Piping Fragility Evaluation: Interaction With High-Rise Building Performance

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Bu Seog Ju ◽  
Abhinav Gupta ◽  
Yong Hee Ryu
Keyword(s):  
Fragility Curves ◽  
Element Model ◽  
System Level ◽  
Building Performance ◽  
Ground Acceleration ◽  
High Rise ◽  
High Rise Building ◽  
Nonstructural Systems ◽  
Critical Facilities ◽  
Nonlinear Finite Element Model

Many recent studies have emphasized the need for improving seismic performance of nonstructural systems in critical facilities in order to reduce the damage as well as to maintain continued operation of the facility after an earthquake. This paper is focused on evaluating system-level seismic fragility of the piping in a representative high-rise building. Piping fragilities are evaluated by incorporating the nonlinear finite-element model of a threaded Tee-joint that is validated using experimental results. The emphasis in this study is on evaluating the effects of building performance on the piping fragility. The differences in piping fragility due to the nonlinearities in building are evaluated by comparing the fragility curves for linear frame and nonlinear fiber models. It is observed that as nonlinearity in the building increases with increasing value of peak ground acceleration, the floor accelerations exhibit a reduction due to degradation/softening. Consequently, the probabilities of failure increase at a slower rate relative to that in a linear frame. It is also observed that a piping located at higher floor does not necessarily exhibits high fragilities, i.e., the fundamental building mode is not always the governing mode. Higher order building modes with frequencies closest to critical piping modes of interest contribute more significantly to the piping fragility. Within a particular building mode of interest, a good indicator of the amplification at different floor levels can be obtained by the product of mode shape ordinate and modal participation factor. Piping fragilities are likely to be higher at floor levels at which this product has a higher value.

Seismic Assessment of Out-of-Code High-Rise Building Using Dynamic Nonlinear Analysis

2011 ◽  
Vol 378-379 ◽  
pp. 292-296
Author(s):  
Xue Shu Wu ◽  
Wan Li Xue ◽  
Guo Rui ◽  
Xu Qian Zhao ◽  
Gu Li
Keyword(s):  
Nonlinear Analysis ◽  
Kinematic Hardening ◽  
Nonlinear Dynamic Analysis ◽  
Shear Walls ◽  
Element Model ◽  
Core Tube ◽  
Shell Elements ◽  
High Rise ◽  
The Core ◽  
High Rise Building

Seismic response of a high-rise building under rare earthquake is numerically investigated in the paper. The Height of the building is 266m, which goes beyond the limit of 150m in Chinese standard, so nonlinear analysis should be performed to investigate its elasto-plastic behaviors under severe earthquake excitations. In the finite-element model for analysis, beam-column members of the structure are simulated by beam elements, while the core tube is simulated by shell elements. The concrete damage plasticity model is used for concrete members, while the kinematic hardening rule is defined for steel beam-column members. Four sets of earthquake wave, including 3 sets of strong earthquake records and 1 set of artificial wave, are adopted in the analysis. The analysis results show that, under severe earthquakes, steel frame members and steel truss members in the strengthened floors keep elastic. Severe damages are detected in almost all coupling beams in the core tube, as well as shear-walls near strengthened stories, where lateral stiffness would decrease seriously. Through the investigation, it is also found that the largest story drift is less than the maximum allowable value in the Chinese code for seismic design of buildings. So it is concluded that the high-rise building will not collapse when the place is subjected to severe earthquakes. Besides, some design suggestions are proposed according to nonlinear dynamic analysis in the paper.

scholarly journals Application of Equivalent Simplified Calculation Model of Isolated Structure in Super High-rise Building

2021 ◽  
pp. 115-123
Author(s):  
Yingjun Wang, Tianli Chen
Keyword(s):  
Shaking Table Test ◽  
Time History ◽  
Calculation Model ◽  
Shaking Table ◽  
Width Ratio ◽  
Vertical Stiffness ◽  
High Rise ◽  
High Rise Building ◽  
Ratio Limit ◽  
Simplified Calculation

In this paper, the application of equivalent simplified calculation model of isolated structure in super high-rise building is studied. In this paper, the characteristics of isolation structures with different height width ratio are analyzed, and the relationship curve between the limit value of height width ratio of isolation structure and the distance of isolation support is established. From the curve, we can estimate the limit height of the isolated structure when the bearing does not produce tensile stress under different seismic intensities. This paper also analyzes the influencing factors of the height width ratio limit, and puts forward the method of increasing the height width ratio limit. In this paper, a vertical stiffness correction model of isolation bearing is proposed. Compared with the shaking table test results and time history analysis, the modified model can truly reflect the mechanical properties of the isolation bearing.

Modeling Dynamic Responses of Viscoelastic Heterogeneous Soft Tissues to Step Acoustic Radiation Force

2013 ◽  
Author(s):  
Xiaodong Zhao ◽  
Assimina A. Pelegri
Keyword(s):  
Soft Tissue ◽  
Dynamic Response ◽  
Soft Tissues ◽  
Acoustic Radiation ◽  
Three Dimensional ◽  
Radiation Force ◽  
Element Model ◽  
Acoustic Radiation Force ◽  
Degree Of Freedom ◽  
Dynamic Responses

The responses of soft tissue under acoustic radiation force excitations are used to image tissue mechanical properties for soft tissue discrimination and detection of breast tumors. The soft tissue viscoelasticy has been interrogated by step acoustic radiation force excitations. The corresponding induced time-dependent creep displacement is used to reconstruct soft tissue viscoelasticity or to estimate viscosity and elasticity contrast of the inclusion to background. The acoustic radiation force is highly localized in a small excitation region; and, one degree-of-freedom and homogenous assumptions are generally made to the analysis. However, these simplifying assumptions limit the accuracy of these methods. In this paper, a finite element model was built to demonstrate the effect of the dynamic response of viscoelastic heterogeneous soft tissue to step acoustic radiation force. Factors affecting the dynamic response of soft tissue were first investigated with the homogenous model, and the corresponding estimation quality based on the one degree-of-freedom model was evaluated. Then, the dynamic response of soft tissue with inclusion and different elasticity and viscocity for the tissue and the inclusion was studied. The results suggest that in order to improve the estimate of soft tissue viscoelasticity the heterogenenous nature of the tissue and its three dimensional geometry should be accounted in the model.

Analysis of Seismic Response Influence of High Rise Building Nearby Subway Station in Soft Site

2012 ◽  
Vol 166-169 ◽  
pp. 2105-2111
Author(s):  
Hui Long ◽  
Guo Xing Chen ◽  
Hai Yang Zhuang
Keyword(s):  
Seismic Response ◽  
Shear Force ◽  
Soft Soil ◽  
Horizontal Displacement ◽  
Element Model ◽  
Subway Station ◽  
High Rise ◽  
High Rise Building ◽  
Dimensional Finite Element ◽  
The Moment

A two-dimensional finite element model for soil-subway station- high rise building was created based on the representative soft soil site along the Nanjing subway to study the nonlinear dynamic interaction among three parts. The influence of two-layer and three-stride island-type subway station was explored on the seismic response of nearby high rise building. The results showed that the natural frequency of high rise building was reduced apparently because of the existence of soft soil. The displacement angle between the layers of high rise buildings and right swing relative horizontal displacement amplitude between top and bottom was increased when the subway station was located at the left of the high rise building. In the same time, the shear force of the beam end and the moment amplitude on the middle span of the first and second floor of high rise building, the shear force of the column end on the fist layer, the shear and moment amplitude of the middle column end and right side column end on underground layer were all increased, and the increase proportion is even up to 30% on certain areas, which could weaken the seismic performance of high rise building.

Seismic Analysis of Multi-Storied Building with Shear Walls using ETABS

2018 ◽  
Vol 8 (3) ◽  
Author(s):  
B. Jaswanth ◽  
Y. L. Surendra ◽  
M. Ravi Kumar
Keyword(s):  
Seismic Analysis ◽  
Shear Walls ◽  
Width Ratio ◽  
Structural Members ◽  
High Rise ◽  
High Rise Building ◽  
Torsion Effect ◽  
Box Structure ◽  
Strength And Stiffness ◽  
Sufficient Strength

Shear walls are structural members used to elongate the strength of R.C.C. structures. These shear walls will be construct in each level of the structure, to form an effective box structure. Equal length shear walls are placed symmetrically on opposite sides of outer walls of the building. Shear walls are added to the building interior to provide more strength and stiffness to the building when the exterior walls cannot provide sufficient strength and stiffness. It is necessary to provide these shear walls when the tolerable span- width ratio for the floor or roof diaphragm is exceeded. The present work deals with a study on the improvement location of shear walls in symmetrical high rise building. Position of shear walls in symmetrical buildings has due considerations. In symmetrical buildings, the center of gravity and center of rigidity coincide, so that the shear walls are placed symmetrically over the outer edges or inner edges (like box shape). So, it is very necessary to find the efficient and ideal location of shear walls in symmetrical buildings to minimize the torsion effect. In this work a high rise building with different places of shear walls is considered for analysis. The multi storey building with 8 story’s is analyzed for its displacement, strength and stability using ETABS-2015 software. For the analysis of the building for seismic loading with Zone-III is considered with soil III. The analysis of the building is done by using equivalent static method and dynamic method.

Performance analysis of global local mean square error criterion of stochastic linearization for nonlinear oscillator

2019 ◽  
Author(s):  
Nguyen Cao Thang ◽  
Luu Xuan Hung
Keyword(s):  
Performance Analysis ◽  
Mean Square Error ◽  
Nonlinear Oscillators ◽  
Degree Of Freedom ◽  
Equivalent Linearization ◽  
Mean Square ◽  
Error Criterion ◽  
Stochastic Linearization ◽  
Local Mean ◽  
Mean Square Error Criterion

The paper presents a performance analysis of global-local mean square error criterion of stochastic linearization for some nonlinear oscillators. This criterion of stochastic linearization for nonlinear oscillators bases on dual conception to the local mean square error criterion (LOMSEC). The algorithm is generally built to multi degree of freedom (MDOF) nonlinear oscillators. Then, the performance analysis is carried out for two applications which comprise a rolling ship oscillation and two degree of freedom one. The improvement on accuracy of the proposed criterion has been shown in comparison with the conventional Gaussian equivalent linearization (GEL).

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