THE ADEQUACY OF A SHEAR BUILDING FOR MODELLING OPEN-PLANE FRAMES UNDER SEISMIC EXCITATION

1997 ◽  
Vol 199 (5) ◽  
pp. 816-824 ◽  
Author(s):  
K.V. Rambabu ◽  
M.M. Allam
Keyword(s):  
Seismic Excitation ◽  
Plane Frames ◽  
Shear Building ◽  
Open Plane

System Identification of High-Rise Building under Unknown Seismic Excitation with Limited Output Measurements

2010 ◽  
Vol 163-167 ◽  
pp. 3947-3951
Author(s):  
Ying Lei ◽  
Chao Liu ◽  
Yong Qiang Jiang
Keyword(s):  
System Identification ◽  
Structural Parameters ◽  
Frequency Equation ◽  
Seismic Excitation ◽  
Element Formulation ◽  
Unknown Inputs ◽  
High Rise ◽  
High Rise Building ◽  
Limited Output ◽  
Shear Building

In this paper, a system identification approach is proposed for high-rise building under unknown seismic excitation with limited output measurements. A high-rise building is decomposed into small size substructures based on its finite element formulation. Interaction effect between adjacent substructures is considered as ‘equivalent known inputs’ to each substructure. Unknown seismic excitation is considered as ‘equivalent unknown inputs’ at the first floor. By sequentially utilizing the extended Kalman estimator for the extended state vectors and the least squares estimation for the ‘equivalent unknown inputs’, structural parameters above the first story of a shear building can be identified. Then, with the analysis of the measured absolute acceleration responses in frequency domain and the peak-picking method for the estimation of the first natural frequency of the building, structural parameters of the first story can be identified from the frequency equation. Finally, the unknown seismic excitation can be identified via the numerical solution of a first-order differential equation. It is shown by a numerical example that the proposed method can identify high-rise building parameters and the seismic excitation with good accuracy.

Representation of soil support in analysis of open plane frames

1995 ◽  
Vol 56 (6) ◽  
pp. 917-925 ◽  
Author(s):  
P.Srinivasa Rao ◽  
K.V. Rambabu ◽  
M.M. Allam
Keyword(s):  
Plane Frames ◽  
Open Plane

Maximum mean square response and critical orientation under bi-directional seismic excitation

2021 ◽  
Vol 233 ◽  
pp. 111881
Author(s):  
Athanasios Tsourekas ◽  
Asimina Athanatopoulou ◽  
Konstantinos Kostinakis
Keyword(s):  
Seismic Excitation ◽  
Mean Square ◽  
Critical Orientation ◽  
Mean Square Response

Damage-Involved Structural Pounding in Bridges under Seismic Excitation

2017 ◽  
Vol 754 ◽  
pp. 309-312 ◽  
Author(s):  
Robert Jankowski
Keyword(s):  
Structural Damage ◽  
Structural Model ◽  
Viscoelastic Model ◽  
Time History ◽  
Seismic Wave Propagation ◽  
Seismic Excitation ◽  
Lumped Mass ◽  
Positive Role ◽  
Contact Points ◽  
Elevated Bridge

During severe earthquakes, pounding between adjacent superstructure segments of highway elevated bridges was often observed. It is usually caused by the seismic wave propagation effect and may lead to significant damage. The aim of the present paper is to show the results of the numerical analysis focused on damage-involved pounding between neighbouring decks of an elevated bridge under seismic excitation. The analysis was carried out using a lumped mass structural model with every deck element discretized as a SDOF system. Pounding was simulated by the use of impact elements which become active when contact is detected. The linear viscoelastic model of collision was applied allowing for dissipation of energy due to damage at the contact points of colliding deck elements. The results show that pounding may substantially modify the behaviour of the analysed elevated bridge. It may increase the structural response or play a positive role, and the response depends on pattern of collisions between deck elements. The results also indicate that a number of impacts for a small in-between gap size is large, whereas the value of peak pounding force is low. On the other hand, the pounding force time history for large gap values shows only a few collisions, but the value of peak pounding force is substantially large, what may intensify structural damage.

Structural Analysis of an Offshore Jacket Model Under Seismic Excitation

2008 ◽  
Author(s):  
Helder J. D. Correia ◽  
Anto´nio C. Mendes ◽  
Carlos A. F. S. Oliveira
Keyword(s):  
Point Of View ◽  
Shaking Table ◽  
Seismic Excitation ◽  
Model Structure ◽  
Structural Members ◽  
Jacket Structures ◽  
Reaction Forces ◽  
Nodal Displacements ◽  
Good Agreement

In the present work the action of earthquakes upon offshore jacket structures is analysed by means of ADINA software. Our case-study refers to an existing model structure, previously constructed at the Laboratory of Fluid Mechanics of UBI, which has been analysed from the hydrodynamic point of view — Mendes et al. [1, 2]. The seismic excitation will be imposed at the base of this model structure, with frequencies and amplitudes corresponding to actual earthquake conditions transposed to the model scale of 1:45. The FEM software is utilised to calculate the natural frequencies of the model and to obtain stresses at selected members, as well as their nodal displacements. Our purpose is to quantify maximum stresses occurring in critical structural members and to verify the survivability criterion. The predictions of the numerical model, in terms of the reaction forces at the base and acceleration at the top of the structure, are then correlated with the experimental measurements performed when the model structure is excited in an especially designed shaking table (Correia [3]), revealing a good agreement between both results.

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