Seismic performance assessment based on damage of structures, Part 1: Theory (original) (raw)
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L Seismic Performance Assesment Based on Damage of Structures – Part 1 : Theory Udc 699
2011
The paper presents methodology for safety assessment and design of earthquake resistant structures based on application of damage spectra. The damage spectrum can be used for seismic evaluation of vulnerability of structures with given properties and can provide information of damage potential of the recorded ground motions. Damage spectrum represents a variation of a damage index versus structural period for a single-degree-of-freedom system subjected to an earthquake ground motion. The improved damage index, based on plastic deformation and hysteretic energy dissipation, is applied. It depends on maximal plastic deformation, ductility capacity and function including cumulative damage effects. This function, besides the parameter including influence of deterioration, depends on the history of cyclic deformations and on both cyclic and accumulative ductility.
Application of Improved Damage Index for Designing of Earthquake Resistant Structures
2002
The paper presents the application of methodology for designing of earthquake resistant structures based on damage assessment. The necessary balance among strength capacity, stiffness and ductility is determined to keep the damage level within prescribed limits. This procedure can be applied to determine necessary deformation or strength capacity for which damage degree of the structure after earthquake is within acceptable (prescribed) limits. The improved damage index proposed in the paper is based on plastic deformation and hysteretic energy dissipation. It is obtained by modifying the well-known ParkAng model through eliminating some of its deficiencies connected with physical meaning of damage index. With the introduction of corrective coefficient the influence of hysteretic energy under monotonically increasing lateral deformation is eliminated. Through this is also included the influence of accumulation of inelastic deformations connected with the history of cyclic deformatio...
Damage spectrum and its applications to performance-based earthquake engineering
Improved damage spectra are proposed to quantify the damage potential of recorded earthquake ground motion. The damage spectra are based on a combination of normalized hysteretic energy and deformation ductility of a series of inelastic single-degree-offreedom systems. The damage spectra proposed will be zero if the structure remains elastic, i.e., no significant damage is expected, and will be unity if there is a potential of collapse. By varying a coefficient in their formulations, improved damage spectra can be reduced to commonly used normalized hysteretic energy or displacement ductility spectra. The damage spectra are computed for hundreds of horizontal ground motions recorded during the Landers and Northridge earthquakes. Source-to-site attenuation of the damage spectra in the Northridge earthquake is examined. Calibration of the damage spectra for an instrumented building damaged during the Northridge earthquake is also carried out. The improved damage spectra are promising for assessment of the performance-based seismic vulnerability of existing structures. For example, following an earthquake, near real-time contour maps of damage spectral ordinates at selected periods provide useful information on the spatial distribution of the damage potential of recorded ground motion for specific types of structures. The concept of damage spectra is also promising for carrying out performance-based design of new structures.
Structural damage evaluation: theory and applications to earthquake engineering
2004
The further development of performance-based earthquake engineering (PBEE) is on the current agenda of the earthquake engineering community. A part of assessing the seismic performance of civil engineering structures involves estimation of seismic damage. The conventional approach to damage estimation is based on fragility functions that relate some chosen parameters of structural response to incurred damage. Therefore, damage prediction is based exclusively on the knowledge of the chosen structural response parameters, meaning that damage analysis is uncoupled from the structural analysis. The structural response parameters selected for use in damage analysis are usually referred to as engineering demand parameters (EDP). In the present study, it is shown that for structural damage estimation, the uncoupled damage analysis has deficiencies that lead to less accurate damage prediction. These shortcomings originate from two sources: first, dependence of practically all EDPs on struct...
Assessment of experimental seismic response through damage evaluation
Proceedings of the 12th World …, 2000
SUMMARY The paper presents a contribution for the assessment of experimental results obtained in seismic tests of structures in a context of fragility analysis for earthquake risk assessment. A methodology is proposed to estimate the vulnerability of specimens tested ...
Overview of damage assessment of structures
Current Science, 2019
Different available analytical and experimental metho-dologies of local and global damage index (LDI and GDI) determination for bridges and buildings along with their mathematical expression are reviewed in this article. In the literature, impact of seismic loading and material deterioration due to ageing effects is the main focus to study the performance. Case studies for assessment of bridges and buildings are appended here to understand variation of damage index (DI) for various levels of seismicity. The utility of the proposed methods has been discussed in this case study. This article also includes progressive development, limitations and directions of future research on damage assessment of structures. Based on the extensive literature review, the authors have critically analysed the pros and cons of the available methods. However, time-dependent damage assessment, damage estimation for various structural and non-structural components using different materials, variation of damage for different configurations of structures, and deterioration of roads and bridges are the probable future scope for research. In future, damage-based design considering multiple response parameters along with uncertain load characteristics such as seismic load, wind load, blast load, floods and accidental load could be considered to select allowable damage of structures that would help to understand and ensure the time-dependent safety, progressive phases of collapse and serviceability with high reliability satisfying smart structural requirements. Keywords: Bridges and buildings, damage index, loss assessment, seismicity. DAMAGE to structures is mainly caused by different environmental factors and ageing. Over the years various methods have been used for damage assessment. In this article, an overview of damage assessment is provided. In 1921, Griffith 1 had introduced fracture mechanics for brittle materials, but practically it has been mostly applied to metallic materials. Kaplan 2 had implemented fracture mechanics for concrete. However, several researchers have shown interest in this approach and excavated this area with proficiency. Damage assessment of a building could be easily done with several damage indices (DIs). DI of the structure could be determined either by balancing, demand and capacity of the structure, or by degradation of some structural property 3. In Lee and Fenves plastic damage model, DI was estimated from nonlinear regression of experimental column test data, concentrating on local tensile damage variables such as drift ratio and moment 4. Another DI was proposed based on cumulative member ductility considering limiting rotation capacity for steel, reinforced concrete (RC) columns, composite beams and composite steel-concrete connection sub-assemblies 5. Damage probability matrices are useful for decisive criteria for strengthening strategies and repairing buildings; Monte Carlo simulation with building strength parameters and ground motions are the variables for it 6. DI has been determined from the pushover curve containing initial and final stiffness 7. Damage could be assessed from the relationship between modal parameters-based GDI and local stiffness degradation along with the ageing effect on structures 8. Further, seismic vulnerability of damaged and undamaged RC bare frames, RC buildings with infill wall considering in-plane behaviour, and combined in-plane and out-of-plane nonlinear behaviour examined under main seismic shock as well as aftershock events 9. A damage curve was derived with the decrease of bending stiffness at the fractured section and DI estimated by strain responses of steel beams for pre-and post-earthquakes 10. Structural damage was presented by flexibility matrices with changes of modal parameters (modal damping, frequency and mode shapes) 11. However, irrespective of structure type and material, the ratio between initial resistance and reduced resistance capacity was calculated as general DI 12. Plastic damage of concrete with thermodynamics laws depending on continuum damage mechanics theory was applied on fibre RC beam column simulated in ABAQUS 13. Global damage index (GDI) of RC structure was estimated considering pseudo plastic hinges 14. Seismic damage of RC members for shear-flexure interaction in inelastic range was analysed, which showed a sound relationship between finite element model and experimental results 15. A structural DI was calculated with curvature and stiffness 16. Inclusion of correlative term 'stiffness' in the Park-Ang DI in Bayesi-an framework was introduced 17. Influence of different durations of aftershock was measured in terms of degradation of strength and stiffness of a structure termed as damage ratio 18. Structural damage was accurately detected using modified Cornwell indicator with genetic algorithm 19. DI also depends on hysteretic energy dissipated by a structural member and a drift ratio of 76 RC
Talenta Conference Series: Energy and Engineering (EE)
Seismic input energy is transmitted into building consists of the kinetic energy, elastic strain energy, damping energy, and hysteretic energy. The amount of the input energy induced by earthquake transmitted into a building depends on earthquake characteristics and building dynamic properties. In this context, the hysteretic energy directly associated with damage to structural members through a parameter which known as the damage index were introduced. For this purposes, influence of earthquake characteristic on energy spectra for SDOF system were described and presented. In addition, influence of structural dynamic properties are also described and discussed. Next, to assess the damage potential to a building under seismic excitation, four story steel moment resisting frame were investigated under three selected ground motion records matching to the response spectra design the new Indonesian code. Furthermore, nonlinear dynamic time history analysis were performed using ABAQUS to ...
Improved Shaking and Damage Parameters for Post-Earthquake Applications
2001
In this study, various ground shaking, response and damage parameters are examined for post-earthquake applications. Peak ground motion values, elastic response spectra, spectrum intensity, drift spectrum, inelastic spectra, and hysteretic energy spectrum are examined. Two improved damage spectra are also examined. The improved damage spectra will be zero if the response remains elastic, and will be unity when the displacement capacity under monotonic deformation is reached. Furthermore, the proposed damage spectra can be reduced to the special cases of normalized hysteretic energy and displacement ductility spectra. The proposed damage spectra are promising for various seismic vulnerability studies and post-earthquake applications. In this study the above parameters are examined. Additionally, improved damage spectra are introduced and examined in details. The damage spectra are based on normalized response quantities of a series of inelastic single-degree-of-freedom (SDOF) systems...
Global damage indexes for the seismic performance assessement of RC structures
Earthquake Engineering & Structural Dynamics, 2009
When performing the seismic risk assessment of new or existing buildings, the definition of compact indexes able to measure the damaging and safety level of structures is essential, also in view of the economic considerations on buildings rehabilitation. This paper proposes two series of indexes, named, respectively, Global Damage Indexes (GDIs), which are representative of the overall structure performance, and Section Damage Indexes (SDIs), which assess the conditions of reinforced concrete (RC) beam-column sections. Such indexes are evaluated by means of an efficient numerical model able to perform nonlinear analyses of the RC frame, based on the continuum damage mechanics theory and fiber approach. An improvement of a two-parameter damage model for concrete, developed by some of the authors, which guarantees a better correlation between the Local Damage Indexes (LDIs) and the material's mechanical characteristics, is also presented. For the reinforcement, a specific LDI, named ‘steel damage index’, which takes into account the plastic strain development and the bar buckling effect, is proposed. The numerical model has been employed to simulate several experimental tests, in order to verify the accuracy of the proposed approach in predicting the RC member's behavior. Nonlinear static and dynamic analyses of two RC frames are carried out. The robustness of the method, as well as the effectiveness of the GDIs in assessing the structural conditions, are demonstrated here. Finally, comparisons between the evolution of GDIs and the achievement of the performance levels as proposed in FEMA 356 are reported. Copyright © 2009 John Wiley & Sons, Ltd.
Consideration of economic vulnerability in seismic performance evaluation of structures
Bulletin of Earthquake Engineering, 2020
Risk (economic, social and environmental) assessment and mitigation have recently gained great attention. It refers to computing the risk of a community's infrastructure associated with natural hazards such as earthquakes, landslides, hurricanes or others. Performance evaluation of structures has until now been based on evaluation of maximum displacements, interstory drifts, deformation patterns, ductility and other similar parameters; a relative economic loss estimation as a performance measure for the structure is the next step that follows, and is what has been investigated in this work. For this study a steel mid-rise structure was designed according to code provisions (ASCE 7-10, NSR-10, AISC-341) using modal spectral analysis, after which it was subjected to an Incremental Dynamic Analysis procedure to evaluate the capacity curve of the building. The capacity analysis was then used to determine damage states and compute fragility curves. Finally, economic relative loss values were assigned to represent each designated damage state, for which the mean damage ratio was computed (in terms of economic loss relative to total replacement cost) as a function of spectral displacement. Assigning a relative loss index to damage states is the critical stage of the analysis.