scholarly journals Sensitivity of the Fragility Curve on Type of Analysis Methods, Applied Ground Motions and Their Selection Techniques

2021 ◽  
Author(s):  
Samreen Fatimah ◽  
Jenna Wong
Keyword(s):  
Dynamic Analysis ◽  
Fragility Curves ◽  
Pushover Analysis ◽  
Nonlinear Dynamic Analysis ◽  
Fragility Curve ◽  
Frame Structure ◽  
Steel Moment Frame ◽  
New Approach ◽  
Multiple Parameters ◽  
The Impact

AbstractFragility curves are the primary way of assessing seismic risk for a building with numerous studies focused on deriving these fragility curves and how to account for the inherent uncertainty in the seismic assessment. This study focuses on a three-story steel moment frame structure and performs a fragility assessment of the building using a new approach called SPO2FRAG (Static Pushover to Fragility) that is based on pushover analysis. This new approach is further compared and contrasted against traditional nonlinear dynamic analysis approaches like Incremental Dynamic Analysis and Multiple Stripe Analysis. The sensitivity of the resulting fragility curves is studied against multiple parameters including uncertainties in ground motion, the type of analysis method used and the choice of curve fitting technique. All these factors influence the fragility curve behavior and this study assesses the impact of changing these parameters.

A New Approach to the Rigid Finite Element Method in Modeling Spatial Slender Systems

2018 ◽  
Vol 18 (02) ◽  
pp. 1850017 ◽  
Author(s):  
Iwona Adamiec-Wójcik ◽  
Łukasz Drąg ◽  
Stanisław Wojciech
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Analysis ◽  
Equations Of Motion ◽  
Nonlinear Dynamic Analysis ◽  
New Approach ◽  
Static And Dynamic Analysis ◽  
Rigid Finite Element Method ◽  
Longitudinal Flexibility ◽  
Element Method

The static and dynamic analysis of slender systems, which in this paper comprise lines and flexible links of manipulators, requires large deformations to be taken into consideration. This paper presents a modification of the rigid finite element method which enables modeling of such systems to include bending, torsional and longitudinal flexibility. In the formulation used, the elements into which the link is divided have seven DOFs. These describe the position of a chosen point, the extension of the element, and its orientation by means of the Euler angles Z[Formula: see text]Y[Formula: see text]X[Formula: see text]. Elements are connected by means of geometrical constraint equations. A compact algorithm for formulating and integrating the equations of motion is given. Models and programs are verified by comparing the results to those obtained by analytical solution and those from the finite element method. Finally, they are used to solve a benchmark problem encountered in nonlinear dynamic analysis of multibody systems.

scholarly journals Optimization of shape memory alloy braces for concentrically braced steel braced frames

2019 ◽  
Vol 9 (1) ◽  
pp. 697-708
Author(s):  
Sasan Babaei ◽  
Panam Zarfam
Keyword(s):  
Dynamic Analysis ◽  
Shape Memory ◽  
Smart Materials ◽  
Fragility Curves ◽  
Nonlinear Dynamic Analysis ◽  
High Strength ◽  
Monte Carlo Analysis ◽  
Braced Frames ◽  
Damage State ◽  
Response Modification Factor

AbstractExpanding the use of smart braced frames to govern the seismic response of structures by providing ductility and elasticity has been hampered and delayed by cost indexes. The braces in frames comprise two segments of expensive shape memory alloys (SMAs) and high-strength steel with high stiffness. These smart materials can reduce seismic damage by providing stiffness, yielding, and phase shifting. In this study, the length of the SMA segments in three- and six-story frames (applied either at all floors or as part of a dual system) was increased to determine the optimal length at a constant period. Performance levels and fragility curves were obtained to evaluate the seismic behavior of the optimized frame. The response modification factor determined based on the static pushover, incremental nonlinear dynamic analysis, and linear dynamic analysis suggests the ductility and over-strength of the optimized frame. The probability of being in or exceeding each damage state was determined with a Monte Carlo analysis and was acceptable and in accordance with previous deterministic analysis results.

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.

Effect of damage limit states on the seismic fragility of reinforced concrete frame-shear wall buildings

2021 ◽  
Vol 14 (9) ◽  
pp. 57-68
Author(s):  
Durga Mibang ◽  
Satyabrata Choudhury
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Analysis ◽  
Seismic Vulnerability ◽  
Design Method ◽  
Fragility Curves ◽  
Nonlinear Dynamic Analysis ◽  
Soil Condition ◽  
Shear Wall ◽  
Reinforced Concrete Frame ◽  
Limit States

Assessment of the seismic vulnerability of frame-shear wall buildings can be performed by non-linear dynamic analysis and it needs detailed analytical modeling, structural performance measures and various earthquake intensities. The codal based design method can hardly be used for designing buildings of pre-defined target objectives whereas the Unified performance-based design (UPBD) method can be designed for buildings of pre-defined target objectives. In the current study, the UPBD method for frame-shear wall buildings has been applied for different performance levels (PL) i.e. Immediate occupancy (IO), Life safety (LS) and Collapse prevention (CP) with 1%, 2% and 3% drift in both the directions of the buildings. The nonlinear dynamic analysis of the reinforced concrete (RC) frame-shear wall buildings is performed considering spectrum compatible ground motions (SCGM) as per EC-8 demand spectrum at 0.45g level and type B soil condition. Vulnerability assessment of the frame-shear wall buildings is conducted by generating fragility curves and the probability failure of structure is checked based on different configurations and damage limit states of the structure. Finally, the outcome of the work gives a proper idea of the nonlinear behavior of the dual system so that optimum design could be acquired for achieving higher safety aspects.

A modal nonlinear static analysis method for assessment of structures under blast loading

2017 ◽  
Vol 24 (16) ◽  
pp. 3631-3640 ◽  
Author(s):  
Amir Saedi Daryan ◽  
Sahman Soleimani ◽  
Hesam Ketabdari
Keyword(s):  
Blast Wave ◽  
Pushover Analysis ◽  
Nonlinear Dynamic Analysis ◽  
Blast Waves ◽  
Nonlinear Static Analysis ◽  
Seismic Excitation ◽  
Wall Structure ◽  
Earthquake Loading ◽  
New Formulation ◽  
The Impact

Modal pushover analysis (MPA) has been developed in previous studies to analyze the response of structures subjected to seismic excitation. Although this method has already been extended for diverse systems of buildings and bridges, its application is currently restricted to earthquake loading. This study is intended to extend this approach for the analysis of structures subjected to other probable loading patterns, such as blast waves and wind loads. For the analysis of structures under seismic excitation, an acceleration is applied to the structure’s base; however, in the case of a blast wave or wind load, the external load is directly applied to the building with an unexpected load pattern. Based on these differences, a new formulation for the modal analysis of structures is developed in this study. To evaluate the method, a shear wall structure is used as a case study, and the impact of a blast wave is considered as an imposed lateral load. The results obtained by the proposed method, called MPA-B, are compared to those of nonlinear dynamic analysis as a benchmark solution. The structural demands that are used as the comparison criteria are story displacement, story drifts and hinge rotations. The results of this evaluation show that the accuracy of the MPA-B method in the analysis of structures under a blast load is similar to the accuracy of the MPA method in the analysis of structures under earthquake loading.

scholarly journals Nonlinear Dynamic Analysis of Masonry Buildings and Definition of Seismic Damage States

2016 ◽  
Vol 10 (1) ◽  
pp. 192-209 ◽  
Author(s):  
A.J. Kappos ◽  
V.K. Papanikolaou
Keyword(s):  
Fragility Curves ◽  
Pushover Analysis ◽  
Nonlinear Dynamic Analysis ◽  
Critical Issue ◽  
Seismic Damage ◽  
Masonry Building ◽  
Nonlinear Behaviour ◽  
Building Stock ◽  
Damage States ◽  
Diaphragm Action

A large part of the building stock in seismic-prone areas worldwide are masonry structures that have been designed without seismic design considerations. Proper seismic assessment of such structures is quite a challenge, particularly so if their response well into the inelastic range, up to local or global failure, has to be predicted, as typically required in fragility analysis. A critical issue in this respect is the absence of rigid diaphragm action (due to the presence of relatively flexible floors), which renders particularly cumbersome the application of popular and convenient nonlinear analysis methods like the static pushover analysis. These issues are addressed in this paper that focusses on a masonry building representative of Southern European practice, which is analysed in both its pristine condition and after applying retrofitting schemes typical of those implemented in pre-earthquake strengthening programmes. Nonlinear behaviour is evaluated using dynamic response-history analysis, which is found to be more effective and even easier to apply in this type of building wherein critical modes are of a local nature, due to the absence of diaphragm action. Fragility curves are then derived for both the initial and the strengthened building, exploring alternative definitions of seismic damage states, including some proposals originating from recent international research programmes.

scholarly journals Development of Seismic Fragility Functions for a Moment Resisting Reinforced Concrete Framed Structure

2016 ◽  
Vol 10 (1) ◽  
pp. 42-51 ◽  
Author(s):  
D. P. McCrum ◽  
G. Amato ◽  
R. Suhail
Keyword(s):  
Reinforced Concrete ◽  
Mechanical Model ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Pushover Analysis ◽  
Frame Structure ◽  
Building Structures ◽  
Reinforced Concrete Structure ◽  
Moment Resisting ◽  
Damage States

Understanding the seismic vulnerability of building structures is important for seismic engineers, building owners, risk insurers and governments. Seismic vulnerability defines a buildings predisposition to be damaged as a result of an earthquake of a given severity. There are two components to seismic risk; the seismic hazard and the exposure of the structural inventory to any given earthquake event. This paper demonstrates the development of fragility curves at different damage states using a detailed mechanical model of a moment resisting reinforced concrete structure typical of Southern Europe. The mechanical model consists of a complex three-dimensional finite element model of the reinforced concrete moment resisting frame structure and is used to define the damage states through pushover analysis. Fragility curves are also defined using the HAZUS macro-seismic methodology and the Risk-UE macro-seismic methodology. Comparison of the mechanically modelled and HAZUS fragility curve shows good agreement while the Risk-UE methodology shows reasonably poor agreement.

Seismic Vulnerability of Reinforced Concrete Building Based on the Development of Fragility Curve: A Case Study

2016 ◽  
Vol 845 ◽  
pp. 252-258 ◽  
Author(s):  
Erlin Wijayanti ◽  
Stefanus Kristiawan ◽  
Edy Purwanto ◽  
Senot Sangadji
Keyword(s):  
Standard Deviation ◽  
Ground Motion ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Pushover Analysis ◽  
Fragility Curve ◽  
Capacity Curves ◽  
Capacity Spectrum ◽  
Damage States ◽  
Spectrum Curve

This study aims to determine the seismic vulnerability of 5th Building of Engineering Faculty, Sebelas Maret University by developing its fragility curves. Fragility curve is a measure of probabilistic seismic performance under various ground motion. The intensity of ground motion adopted in this study is median spectral displacement, , with lognormal standard deviation, βds as uncertainty parameter. The value of lognormal standard deviation is adopted from HAZUS. The parameters of median spectral displacements are identified from the capacity spectrum curve. The capacity curve obtained from non-linear static pushover analysis. Capacity curves can be converted into capacity spectrum to identify the location of the median spectral displacement at various damage states. The obtained fragility curves provide information on the probability of various damage states to occur when certain ground motion level strikes the building under study.

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