A QUASISTATIC ANALYSIS METH OD TO IMPROVE COLLAPSE MECHANISM ANALYSES OF MULTISTORY BUILDINGS
Author: Masato SAITOH , Masaki IKEGAME and Shiro TANAMURA | Size: 0.45 MB | Format:PDF | Quality:Unspecified | Publisher: 13th World Conference on Earthquake Engineering Vancouver, B.C., Canada Paper No. 1284 | Year: August 1-6, 2004 | pages: 10
This study proposes a quasi-static analysis method to improve the reliability of conventional collapse
mechanism analyses of multi-story buildings. This method is based on the hypothesis that the incremental
deformations of the buildings subjected to earthquakes are proportional to the eigenvectors evaluated by using equivalent story stiffness and damping. In this method, the incremental displacements proportional to the eigenvectors are accumulated in the story drifts of the buildings; the eigenvectors are estimated by performing modal analyses whenever an inelastic event occurs in the stories. The analytical results indicate that the conventional pushover analysis generally overestimates the first story drift, while the quasi-static method tends to give good agreements with the results evaluated by the time history analysis.
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Pushover analysis for the seismic response prediction of cable-stayed bridges under multi-directional excitation
Author: A. Cámara *, MA Astiz Department of Mechanics and Structures, School of Civil Engineering, Technical University of Madrid, Prof. Aranguren s/n, Madrid, Spain | Size: 5.9 MB | Format:PDF | Quality:Unspecified
Cable-stayed bridges represent nowadays key points in transport networks and their seismic behavior needs to be fully understood, even beyond the elastic range of materials. Both nonlinear dynamic (NL- RHA) and static (pushover) procedures are currently available to face this challenge, each with intrinsic advantages and disadvantages, and their applicability in the study of the nonlinear seismic behavior of cable-stayed bridges is discussed here. The seismic response of a large number of finite element models with different span lengths, tower shapes and class of foundation soil is obtained with different procedures and compared. Several features of the original Modal Pushover Analysis (MPA) are modified in light of cable-stayed bridge characteristics, furthermore, an extension of MPA and a new coupled pushover analysis (CNSP) are suggested to estimate the complex inelastic response of such outstanding structures subjected to multi-axial strong ground motions.
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SING THE NEW SAP2000 OPEN APPLICATION PROGRAMMING INTERFACE TO DEVELOP AN INTERACTIVE FRONT-END FOR THE MODAL PUSHOVER ANALYSIS OF BRIDGES
Author: A. G. Sextos and G. K. Balafas | Size: 0.72 MB | Format:PDF | Quality:Unspecified | Publisher: COMPDYN 2011 3rd ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering M. Papadrakakis, M. Fragiadakis, V. Plevris (eds.) Corfu, Greece, | Year: 25–28 May 2011 | pages: 14
Seismic assessment of bridge structures often requires inelastic (static or dynamic) analysis methods to be used, in order to draw a realistic evaluation of the structural behaviour
beyond the elastic range. While the widely-used non-linear static (pushover) analysis provides a low-computational-cost approach to this direction, it is inherently limited by the assumption that the structure's response is solely controlled by its fundamental mode. This limitation is raised by an extension of the “standard” pushover analysis (SPA) to take into consideration the effect of higher modes , a method known as Modal Pushover Analysis (MPA). This method however, can often prove to be time-consuming and strenuous both for pre- and post processing. The latter, provided the motivation for investigating the feasibility to take advantage of the recently released SAP2000 application programming interface (API) in order to develop a new computational tool that implements the MPA specifications for evaluating the seismic behavior of bridges in an organized and automatic fashion. The paper concludes with the application and demonstration of the software developed, for the case of an existing reinforced concrete bridge located along the Egnatia Highway in Greece.
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APPLICATION OF PUSHOVER ANALYSIS METHODS FOR BUILDING STRUCTURES
Author: A. Kiran1 , G. Ghosh2 and Y. K.Gupta3 | Size: 0.2 MB | Format:PDF | Quality:Unspecified | Publisher: ISET GOLDEN JUBILEE SYMPOSIUM Indian Society of Earthquake Technology Department of Earthquake Engineering Building IIT Roorkee, | Year: Roorkee October 20-21, 2012 | pages: 6
To have a reliable estimate of the performance of a structure, sophisticated analytical tools are necessary. Nonlinear
dynamic analysis is the most accurate method available for the analysis of structures subjected to earthquake excitation. Nonlinear static (Pushover) Analysis is also an attractive choice because of its simplicity and ability to identify component and system-level deformation demands with accuracy comparable to dynamic analysis. Many methods have evolved, over the years, for pushover analysis of structures. People have a lot of doubt about which one of those will be the most preferred pushover method for the analysis of structures. To fulfill that objective, in the
present study, a comparison has been made between the results of the pushover analysis with the dynamic timehistory
analysis, with a view to find out the most preferred pushover method. The existing pushover analysis methods as per the literatures and codes have been considered in the study. For the analysis purpose, two types of building structures have been considered. It has been observed that in most of the cases, pushover analysis results are conservative as compared to the time history results. It has been observed that in most of the cases ELM method of FEMA 440 gives good result in comprasion to time history analysis.
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Author: Gr. G. Penelis1 , A.J. Kappos1 | Size: 0.33 MB | Format:PDF | Quality:Unspecified | Publisher: Published by Elsevier Science Ltd. Earthquake Engineering Paper Reference 015 | pages: 10
A methodology is presented for modelling the inelastic torsional response of buildings in nonlinear static (pushover) analysis, aiming to reproduce to the highest possible degree the results of inelastic dynamic time history analysis. The load vectors are defined using dynamic elastic spectral analysis while the dynamic characteristics of an equivalent single mass system, which incorporates both translational and torsional modes, are derived using an extension of earlier methods based on the SDOF approach. The proposed method is verified for the case of single-storey monosymmetric buildings.
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Owing to the simplicity of inelastic static pushover analysis compared to inelastic dynamic analysis, the study of this technique
has been the subject of many investigations in recent years. In this paper, the validity and the applicability of this technique are
assessed by comparison with ‘dynamic pushover’ idealised envelopes obtained from incremental dynamic collapse analysis. This
is undertaken using natural and artificial earthquake records imposed on 12 RC buildings of different characteristics. This involves
successive scaling and application of each accelerogram followed by assessment of the maximum response, up to the achievement of the structural collapse. The results of over one hundred inelastic dynamic analyses using a detailed 2D modelling approach for each of the twelve RC buildings have been utilised to develop the dynamic pushover envelopes and compare these with the static pushover results with different load patterns. Good correlation is obtained between the calculated idealised envelopes of the dynamic analyses and static pushover results for a defined class of structure. Where discrepancies were observed, extensive investigations based on Fourier amplitude analysis of the response were undertaken and conservative assumptions were recommended.
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hi my friends
i need a paper which could help me to Verification my Thesis . it's about seismic performance analysis of FRP reinforced concrete frame (two span - two story) .
i need to experimental results of two span-two story concrete frame .
is it possible to introduce a source for control Verification my numerical model ?
regards.
beh.
Prior to 1970, design practice tended to consider the ground and the structure in relative isolation. The Institution of Structural Engineers, in support of the need for recognition to be given to interactive effects, formed a special study group in 1971 to study the matter and make recommendations. This led to the setting up of an ad hoc committee which prepared the state of the art report –Structure-Soil Interaction - published in 1978.
In accordance with institution procedures the relevance of the 1978 document to current practice was reviewed and the need for revision and extension was identified. The Institution with the cooperation of the Institution of Civil Engineers and the International Association for Bridge and Structural Engineering, has responded to the current demand for adequate definition of the problems presented by the interactive effects and has initiated the preparation of this comprehensive guidance covering most types of structure.
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Soft storey buildings are characterized by having a storey which has a lot of open spaces. This soft
storey creates a major weak point in an earthquake. Since soft stories are classically associated with
retail spaces and parking garages, they are often on the lower stories of a building, which means that
when they collapse, they can take the whole building down with them, causing serious structural damage
which may render the structure totally unusable. In this study, efforts have been given to examine the
effect of incorporation of isolator on the seismic behavior of buildings subjected to the appropriate
earthquake for medium risk seismicity region. It duly ensures incorporating isolator with all relevant
properties as per respective isolators along with its time period and damping ratio. Effort has also been
made here to build up a relationship for increasing storey height and the changes for incorporating
isolator with same time period and damping ratio for both lead rubber bearing (LRB) and high damping
rubber bearing (HDRB). Dynamic analyses have been carried out using response spectrum and time
history analysis. Behavioral changes of structural parameters are investigated. The study reveals that the
values of structural parameters reduce a large amount while using isolator. However, LRB is found
beneficial than HDRB. The structure experiences huge storey drift at the soft storey level that may be
severe and cause immature failure. The amount of masonry infill is very vital for soft storey buildings as
its decrement increases reasonable displacements.
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