The Seismic Response Study of Light Steel Storey Adding Structure Considering the Effects of Damping

2014 ◽  
Vol 1030-1032 ◽  
pp. 948-951
Author(s):  
Xue Qing Tang ◽  
Pei Cheng Wu ◽  
Shou Cai Ma
Keyword(s):  
Dynamic Properties ◽  
Response Spectrum ◽  
Earthquake Response ◽  
Superposition Method ◽  
Correction Formula ◽  
Mode Superposition Method ◽  
Development Direction ◽  
Damping Theory ◽  
Complex Damping ◽  
Research Situation

This paper summarized the current research situation and development direction of the storey adding structure all over the country. On the basis of the situation, combined characteristics of light steel storey adding structure, the article analyzed adding structure's damping distribution regularity. Based on the complex damping theory, through the mode-superposition method, there was established the correction formula of the earthquake response spectrum of light steel storey adding structure considered the effects of damping. All above, the article provides the basis for the study on the dynamic properties of light steel storey adding structure.

Seven Mega Floor MSCSS Modal Analysis

2013 ◽  
Vol 353-356 ◽  
pp. 2210-2215
Author(s):  
Jun Jun Wang ◽  
Lu Lu Yi
Keyword(s):  
Modal Analysis ◽  
Response Spectrum ◽  
Time History ◽  
Response Analysis ◽  
Superposition Method ◽  
Response Spectrum Analysis ◽  
Mode Superposition Method ◽  
History Analysis ◽  
Basic Performance ◽  
Dynamic Time

Modal analysis is also known as dynamic analysis for mode-superposition method. In the seismic response analysis of linear structural systems, it is one of the most commonly used and the most effective ways. Through the modal analysis of building structure, we can get some basic performance parameters of the structure. These parameters can help us make qualitative judgments for the respond of a structure first, and can help us judge whether they meet demands for conceptual design. Modal analysis is also the basis of other dynamic response analysis, including dynamic time history analysis and response spectrum analysis.

Optimization Based Identification of the Dynamic Properties of Linearly Viscoelastic Materials Using Vibrating Beam Technique

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Zhiyong Ren ◽  
Noureddine Atalla ◽  
Sebastian Ghinet
Keyword(s):  
Dynamic Properties ◽  
Steel Specimen ◽  
Direct Result ◽  
Superposition Method ◽  
Optimization Approach ◽  
Viscoelastic Materials ◽  
Master Curves ◽  
Mode Superposition Method ◽  
Viscoelastic Core ◽  
Beam Technique

Sandwich structures with viscoelastic core and metal face sheets are increasingly used in automotive industry to significantly reduce the amplitude of vibration and noise radiation. Several experimental methods such as dynamic mechanical analysis (DMA) and vibrating beam technique (VBT) are used to characterize the dynamic properties of viscoelastic materials as a function of frequency and temperature. This paper investigates the use of a free-free beam setup, as an alternative solution to the classical clamped-free VBT, for a better control of the effect of boundary conditions on the laminated steel specimen. The new setup is developed in combination with a frequency response function based optimization method, to automatically derive the dynamic properties of viscoelastic core materials and generate their master curves. A solver based on the normal mode superposition method, considering the added mass effect of the impedance head, is used in the cost function of the optimization approach. The sandwich model is based on the Ross–Kerwin–Ungar equation, and the four-parameter fractional derivative model is used in conjunction with the Williams–Landel–Ferry equation to describe the frequency and temperature dependent behavior of the viscoelastic material. The master curves are a direct result of the optimization process. Several applications are described to assess the performance of the present method. In particular, a systematic comparison with both the classical VBT and DMA (when available) is presented.

Research on Dynamic Properties of Concrete Steel Tubular Arch Bridge Based on ANSYS

2011 ◽  
Vol 71-78 ◽  
pp. 3233-3236 ◽  
Author(s):  
Rong He ◽  
Wei He ◽  
Guo Hua Geng
Keyword(s):  
Dynamic Response ◽  
Dynamic Characteristics ◽  
Dynamic Properties ◽  
Superposition Method ◽  
Vibration Frequencies ◽  
Fem Model ◽  
Arch Bridge ◽  
Mode Superposition Method ◽  
Definition Of

Based on ANSYS for modal analysis of bridges, the basic steps includes: building up the FEM model, applying the load and solving the model, expanding the mode, observing the results and so on. Taking the Friendship Avenue Arch Bridge as an example, the building procedures of FEM model were described from the definition of member section, element selection, and the determination of relevant attributes. At last, the dynamic characteristics of the bridge were analyzed based on ANSYS. The results showed that the first 10th order vibration frequencies of the Friendship Avenue Arch Bridge ranged from 1.3Hz to 3.1Hz, and the more order modes should be considered when calculated the dynamic response based on the mode superposition method.

scholarly journals Earthquake response of heavily damaged historical masonry mosques after restoration

2017 ◽  
Vol 17 (10) ◽  
pp. 1811-1821 ◽  
Author(s):  
Ahmet Can Altunışık ◽  
Ali Fuat Genç
Keyword(s):  
Element Model ◽  
Earthquake Response ◽  
Shear Stresses ◽  
Superposition Method ◽  
Seismic Zone ◽  
Principal Stresses ◽  
Mode Superposition Method ◽  
Earthquake Load ◽  
Historical Masonry ◽  
Restoration Work

Abstract. Restoration works have been accelerated substantially in Turkey in the last decade. Many historical buildings, mosques, minaret, bridges, towers and structures have been restored. With these restorations an important issue arises, namely how restoration work affects the structure. For this reason, we aimed to investigate the restoration effect on the earthquake response of a historical masonry mosque considering the openings on the masonry dome. For this purpose, we used the Hüsrev Pasha Mosque, which is located in the Ortakapı district in the old city of Van, Turkey. The region of Van is in an active seismic zone; therefore, earthquake analyses were performed in this study. Firstly a finite element model of the mosque was constructed considering the restoration drawings and 16 window openings on the dome. Then model was constructed with eight window openings. Structural analyses were performed under dead load and earthquake load, and the mode superposition method was used in analyses. Maximum displacements, maximum–minimum principal stresses and shear stresses are given with contours diagrams. The results are analyzed according to Turkish Earthquake Code (TEC, 2007) and compared between 8 and 16 window openings cases. The results show that reduction of the window openings affected the structural behavior of the mosque positively.

scholarly journals Earthquake Response of Heavily Damaged Historical Masonry Mosques after Restoration

2017 ◽  
Author(s):  
Ahmet Can Altunışık ◽  
Ali Fuat Genç
Keyword(s):  
Element Model ◽  
Earthquake Response ◽  
Shear Stresses ◽  
Superposition Method ◽  
Seismic Zone ◽  
Structural Behaviour ◽  
Principal Stresses ◽  
Mode Superposition Method ◽  
Historical Masonry ◽  
Restoration Work

Abstract. Restoration works have been accelerated substantially in Turkey in the last decade. Many historical buildings, mosques, minaret, bridges, towers etc. structures are restored. With these restorations an important issue arises, namely how restoration work affects the structure. For this reason it is aimed to investigate the restoration effect on the earthquake response of a historical masonry mosque with considering the openings on masonry dome. For this purpose, Hüsrev Pasha Mosque which is located in Ortakapı district in old city of Van, Turkey. The region of Van is in an active seismic zone therefore earthquake analyses were made in this study. Firstly finite element model of the mosque was constructed considering the restoration drawings and 16 window openings on dome. Then model was constructed with 8 window openings. Structural analyses were made under dead and earthquake loads and Mode Superposition Method was used in analyses. Maximum displacements, maximum-minimum principal stresses and shear stresses are given with contours diagrams. The results are investigated according to Turkish Earthquake Code (2007) and compared between 8 and 16 window openings cases. The results show that reduction of the window openings affected the structural behaviour of the mosque positively.

scholarly journals MECHANICAL BEHAVIOR OF HORIZONTAL SWIVEL SYSTEM WITH UHPC SPHERICAL HINGE UNDER SEISMIC ACTION

2021 ◽  
Vol 30 (2) ◽  
Author(s):  
Jiawei Wang ◽  
Bing Cao ◽  
Bo Huang ◽  
Yihan Du
Keyword(s):  
Optimization Algorithm ◽  
Seismic Waves ◽  
Response Spectrum ◽  
Time History ◽  
Bending Moment ◽  
Simulation Models ◽  
Superposition Method ◽  
Seismic Action ◽  
Mode Superposition Method ◽  
Spherical Hinge

In the process of rotation, the total weight of the bridge structure is jointly supported by the spherical hinge and the supporting structure, and its lateral stability is poor. It is easy to lose stability under the action of dynamic loads such as seismic action effect. The present paper takes a 10,000-ton continuous rigid frame swivel bridge as the re-search object, analyzes the dynamic response of the seismic action to the horizontal swivel system, and establishes several structure simulation models. Eighteen seismic waves in three directions that meet the calculation requirements are screened for time history analysis and compared with the response spectrum method. Finally, an optimization algorithm for the seismic response of the bridge under horizontal swivel system is proposed based on the mode superposition method. The UHPC spherical hinge bears all the vertical forces and 20% of the bending moment caused by the seismic action, the support structure bearing the remaining 80% of the bending moment. The optimization algorithm proposed in this paper features high accuracy.

scholarly journals Transient Response of Bridge Piers to Structure Separation under Near-Fault Vertical Earthquake

2021 ◽  
Vol 11 (9) ◽  
pp. 4068
Author(s):  
Wenjun An ◽  
Guquan Song
Keyword(s):  
Large Scale ◽  
Bending Moment ◽  
Relative Displacement ◽  
Superposition Method ◽  
Longitudinal Displacement ◽  
Transient Wave ◽  
Vibration Period ◽  
Vertical Excitation ◽  
Mode Superposition Method ◽  
Main Girder

Given the possible separation problem caused by the double-span continuous beam bridge under the action of the vertical earthquake, considering the wave effect, the transient wave characteristic function method and the indirect mode superposition method are used to solve the response theory of the bridge structure during the earthquake. Through the example analysis, the pier bending moment changes under different vertical excitation periods and excitation amplitudes are calculated. Calculations prove that: (1) When the seismic excitation period is close to the vertical natural vibration period of the bridge, the main girder and the bridge pier may be separated; (2) When the pier has a high height, the separation has a more significant impact on the longitudinal displacement of the bridge, but the maximum relative displacement caused by the separation is random; (3) Large-scale vertical excitation will increase the number of partitions of the structure, and at the same time increase the vertical collision force between the main girder and the pier, but the effect on the longitudinal displacement of the form is uncertain; (4) When V/H exceeds a specific value, the pier will not only be damaged by bending, but will also be damaged by axial compression.

Measured natural periods of concrete shear wall buildings: insights for the design of Canadian buildings

2012 ◽  
Vol 39 (8) ◽  
pp. 867-877 ◽  
Author(s):  
Damien Gilles ◽  
Ghyslaine McClure
Keyword(s):  
Seismic Analysis ◽  
Dynamic Properties ◽  
Response Spectrum ◽  
Shear Wall ◽  
Mode Shapes ◽  
Design Stage ◽  
Base Shear ◽  
Period Equation ◽  
Input Load ◽  
Structural Engineers

Structural engineers routinely use rational dynamic analysis methods for the seismic analysis of buildings. In linear analysis based on modal superposition or response spectrum approaches, the overall response of a structure (for instance, base shear or inter-storey drift) is obtained by combining the responses in several vibration modes. These modal responses depend on the input load, but also on the dynamic characteristics of the building, such as its natural periods, mode shapes, and damping. At the design stage, engineers can only predict the natural periods using eigenvalue analysis of structural models or empirical equations provided in building codes. However, once a building is constructed, it is possible to measure more precisely its dynamic properties using a variety of in situ dynamic tests. In this paper, we use ambient motions recorded in 27 reinforced concrete shear wall (RCSW) buildings in Montréal to examine how various empirical models to predict the natural periods of RCSW buildings compare to the periods measured in actual buildings under ambient loading conditions. We show that a model in which the fundamental period of RCSW buildings varies linearly with building height would be a significant improvement over the period equation proposed in the 2010 National Building Code of Canada. Models to predict the natural periods of the first two torsion modes and second sway modes are also presented, along with their uncertainty.

scholarly journals Identification of Acoustic-Vibratory System by Acoustic Measurement

1996 ◽  
Vol 3 (1) ◽  
pp. 27-37
Author(s):  
Takuzo Iwatsubo ◽  
Shozo Kawamura ◽  
Masahito Kamada
Keyword(s):  
Inverse Analysis ◽  
Coefficient Matrix ◽  
Superposition Method ◽  
Vibration Modes ◽  
Identification Problems ◽  
Mathematical Property ◽  
Vibratory System ◽  
Stochastic Error ◽  
Mode Superposition Method ◽  
Ill Conditioning

A new method for reducing ill-conditioning in a class of identification problems is proposed. The key point of the method is that the identified vibration of the sound source is expressed as a superposition of vibration modes. The mathematical property of the coefficient matrix, the practical error expanding ratio, and the stochastic error expanding ratio are investigated in a numerical example. The mode-superposition method is shown to be an effective tool for acoustic-vibratory inverse analysis.

scholarly journals Dynamic Impact Factor Determination of an Existing Pre-stressed Concrete I-Girder Bridge Using Vehicle-Bridge Interaction Modelling

2021 ◽  
Vol 10 (3) ◽  
pp. 163-176
Author(s):  
Shuvrodeb Adhikary ◽  
Shohel Rana ◽  
Jerin Tasnim ◽  
Nazrul Islam
Keyword(s):  
Impact Factor ◽  
Dynamic Model ◽  
Superposition Method ◽  
Dynamic Impact ◽  
Mode Superposition Method ◽  
Road Roughness ◽  
Girder Bridge ◽  
Dynamic Impact Factor ◽  
Interaction Problem

The dynamic Impact Factor (IM) of a bridge is influenced by many factors, including Vehicle-Bridge Interaction (VBI), vehicle speed and road roughness. This paper represents the dynamic effects of moving vehicles and the determination of IM of an existing Pre-stressed concrete I-girder bridge utilizing VBI modeling. Evaluation of the IM is expected to provide valuable information for condition assessment and management of the existing bridge. The interaction problem between the vehicle and the bridge includes a dynamic model for the bridge structure subsystem, a dynamic model for the vehicle subsystem, interaction constraints, road roughness modelling and numerical solution techniques for the dynamic systems. The Half-car model is utilized for modelling of the vehicle dynamics and the bridge dynamic model is idealized according to Finite Element Method (FEM). Then FEM along with the mode superposition method are utilized for determining the Equation of Motion (EOM) for the bridge subsystem. D’Alembert’s principle is used for developing EOM for the vehicle subsystem. The interaction between vehicle vibration and bridge vibration is established through the contact forces between the wheels and the bridge by employing the compatibility relationship between the contact points and by applying the static equilibrium condition. Lastly, Newmark’s-β method is used for solving the coupled mathematical model of the vehicle and bridge interaction problem to determine the responses of the two sub-systems. The whole procedure is then performed for different vehicle speeds and various bridge deck surface roughness conditions to determine the dynamic impact on the existing I-girder bridge named Teesta Bridge located in Bangladesh.

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