scholarly journals Evaluation of Modal and FEMA Pushover Procedures Using Strong-Motion Records of Buildings

2005 ◽  
Vol 21 (3) ◽  
pp. 653-684 ◽  
Author(s):  
Rakesh K. Goel
Keyword(s):  
Pushover Analysis ◽  
Strong Motion ◽  
Northridge Earthquake ◽  
Reasonable Estimate ◽  
Modal Pushover Analysis ◽  
Higher Mode Effects ◽  
Mode Effects ◽  
Nonlinear Static Procedure ◽  
Nonlinear Static ◽  
Fema 356

The objective of this investigation is to evaluate the FEMA-356 Nonlinear Static Procedure (NSP) and a recently developed Modal Pushover Analysis (MPA) procedure using recorded motions of four buildings that were damaged during the 1994 Northridge earthquake. For this purpose, displacements and drifts from the FEMA-356 NSP and the MPA procedures are compared with the values “derived” from the recorded motions. It is found that the FEMA-356 NSP typically underestimates the drifts in upper stories and overestimates them in lower stories when compared to the recorded motions. Among the four FEMA-356 distributions considered, the “Uniform” distribution led to the most excessive underestimation or overestimation indicating that the need to carefully reevaluate the usefulness of this distribution in the FEMA-356 NSP. Furthermore, FEMA-356 distributions failed to provide accurate estimates of story drifts for a building that satisfied the FEMA-356 criterion for detecting the presence of higher mode effects indicating the need to carefully re-examine this criterion. The MPA procedure, in general, provides estimates of the response that are much closer to the values from the recorded motion compared to those from the FEMA-356 NSP. In particular, the MPA procedure, unlike the FEMA-356 NSP, is able to capture the effects of higher modes. For a building that exhibits dominant effects of “soft” first story, however, neither the MPA procedure nor the FEMA-356 NSP led to reasonable estimate of the response.

Evaluation of Nonlinear Static Procedures in the Assessment of Building Frames

2013 ◽  
Vol 29 (4) ◽  
pp. 1459-1476 ◽  
Author(s):  
Rui Pinho ◽  
Mário Marques ◽  
Ricardo Monteiro ◽  
Chiara Casarotti ◽  
Raimundo Delgado
Keyword(s):  
Dynamic Analysis ◽  
Adaptive Capacity ◽  
Nonlinear Dynamic ◽  
Pushover Analysis ◽  
Nonlinear Dynamic Analysis ◽  
Capacity Spectrum Method ◽  
Modal Pushover Analysis ◽  
Spectrum Method ◽  
Capacity Spectrum ◽  
Nonlinear Static

In recent years a number of nonlinear static procedures (NSPs) have been developed and proposed. Such pushover-based seismic assessment procedures are relatively straightforward to employ and are generally chosen over nonlinear dynamic analysis, especially within the realm of design office application. Parametric comparisons between the different NSPs available, however, are still somewhat sparse. In this work, five commonly employed NSPs (the N2 method, capacity spectrum method, modal pushover analysis, adaptive modal combination procedure, and the adaptive capacity spectrum method) are applied in the assessment of 16 frames subjected to a large number of input motions with a view to assess the accuracy level of such approaches through comparison with nonlinear dynamic analysis results. The evaluation shows that all the NSPs are able to accurately predict displacements and to produce reasonable estimates for other response parameters, with limited dispersion. Even though no single NSP tested led to consistently superior results, modal pushover analysis and the adaptive capacity spectrum method seemed to perform slightly better.

On a Process of Rapid Estimation of Seismic Demands for Generic Steel Frame Structures

2005 ◽  
Author(s):  
Chiung-Yueh Lin ◽  
Wei-Zhi Chen ◽  
Tysh-Shang Jan
Keyword(s):  
Pushover Analysis ◽  
Tall Buildings ◽  
Frame Structures ◽  
Seismic Demands ◽  
Higher Mode Effects ◽  
Mode Effects ◽  
History Analysis ◽  
Story Drift ◽  
Response History Analysis ◽  
Nonlinear Response History Analysis

The seismic demands of tall buildings can be evaluated by nonlinear response history analysis with some more representative, site-dependent, earthquakes, or by pushover analysis. However, the process of the evaluation is tedious and time consuming. Therefore, it is desirable to have a simplified process that provides quick and reasonable estimates of seismic demands, especially in the stage of conceptual (preliminary) design. Gupta & Krawinkler (2000) has reached on a process in the estimation of roof and story drift demands for frame structures from the spectral displacement at the first period of the structure, through a series of modification factors, accounting for MDOF effects, inelasticity effects, and P-delta effects. It is found that this process can estimate seismic demands reasonably, provided that no negative post-yield story stiffness exists. Also, the modification factors are uniform or with reasonable dispersion, except for structures dominated by higher mode effects. This study has conducted a similar research by performing simulations on Taiwan code–compliant structures of different heights (2,5,10,20 and 30 stories), located in different seismic zones and subjected to sets of local ground motions. The feature of this study is that the seismic demands are estimated from the SRSS of the elastic, modal roof displacements of the structure, instead of the first mode spectral displacement. The simulation results have shown that the modification factors are more promising — uniform or with more reasonable dispersion — even the structure is dominated by high mode effects. Therefore, it is concluded that the process proposed in this study is a feasible method and the modification factors obtained in this study are useful for local engineer in engineering applications.

scholarly journals Application of the Incremental Modal Pushover Analysis to Bridges Subjected to Near-Fault Ground Motions

2020 ◽  
Vol 10 (19) ◽  
pp. 6738
Author(s):  
Alessandro Vittorio Bergami ◽  
Gabriele Fiorentino ◽  
Davide Lavorato ◽  
Bruno Briseghella ◽  
Camillo Nuti
Keyword(s):  
Ground Motion ◽  
Pushover Analysis ◽  
Vertical Component ◽  
Structural Response ◽  
Strong Motion ◽  
Seismic Action ◽  
Modal Pushover Analysis ◽  
Near Fault ◽  
Modal Pushover

Near-fault events can cause severe damage to civil structures, including bridges. Many studies have demonstrated that the seismic assessment is not straightforward. Usually, dealing with near-fault ground motion, the structural analysis is performed using Nonlinear Response-History Analysis (NRHA) but in the last years, many authors have tested existing pushover-based procedures originally developed and validated using far-field events. Between those procedures, the Incremental Modal Pushover Analysis (IMPAβ) is a pushover-based procedure specifically developed for bridges that, in this work, was applied to a case study considering near-fault pulse-like ground motion records. The records were analyzed and selected from the European Strong Motion Database. In the paper the results obtained with IMPAβ together with other standard pushover procedures, are compared with NRHA and incremental dynamic analyses; the vertical component of the motion has been also considered. Results obtained with the bridge case study demonstrate that the vertical seismic action has a minor influence on the structural response and that IMPAβ is confirmed as a very effective pushover-based method that can be applied also for near-fault events.

scholarly journals Estimation of Nonlinear Static Damage Index for Seismic Assessment

2021 ◽  
Vol 9 (VII) ◽  
pp. 3688-3695
Author(s):  
Mrs. Ramatai Somwanshi
Keyword(s):  
Response Spectrum ◽  
Pushover Analysis ◽  
Damage Index ◽  
Practical Method ◽  
Damage Function ◽  
Nonlinear Static Analysis ◽  
Concrete Frames ◽  
Maximum Displacement ◽  
Nonlinear Static Procedure ◽  
Nonlinear Static

The main objective of this study is, evaluation damage index of reinforced concrete moment resisting frames by” NONLINEAR STATIC PROCEDURE” nonlinear static analysis includes the capacity spectrum method (CSM) that uses the intersection of the capacity (pushover) curve and a reduced response spectrum to estimate maximum displacement in terms of damage of building. Nonlinear static procedure is simple and practical method for static damage index. For this purpose, first some functions are derived to estimate damage to the structure using pushover analysis and then designed procedure is proposed. In this study damage function is estimated by using correlation between park-ang damage index (NLDD) and nonlinear static damage index (NLSD) which is based on the pushover analysis. For this purpose dynamic and static damage damage analysis are performed on several concrete frames subjected to various earthquake acceleration records. So the detail explanation is found in this study.

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