Impact of the type of the target response spectrum for ground motion selection and of the number of ground motions on the pushover-based seismic performance assessment of buildings

Sinković, Nuša Lazar; Dolšek, Matjaž; Žižmond, Jure

doi:10.1016/j.engstruct.2018.08.066

Cited by 10 publications

(6 citation statements)

References 25 publications

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“…The standard deviation was assumed to be equal to β Se,C = 0.40 . For this particular example, S e,C,a was estimated to amount to 1.69 g. S e,NC,a was then calculated by using (Equation ):

S_{e, italicNC, a} = \frac{S_{e, C, a}}{γ_{italicls}} = \frac{1.69 g}{1.15} = 1.47 g .

The results of the assessments of structures in previous studies show that typical values of the overstrength reduction factor r s of multistorey reinforced concrete frame buildings designed according to Eurocodes 2 and 8 vary from around 2 to 3, whereas the values of ductility of the structure associated with the NC limit state μ NC vary from around 5 to 8 . Based on these boundary values, the overstrength reduction factor and ductility were estimated as r s = 2 and μ NC = 6, respectively.…”

Section: Example: Estimation Of a Risk‐targeted Seismic Action Forcementioning

confidence: 99%

“…The investigated building is a six-storey reinforced concrete frame ( Figure 4A, see also Lazar et al 59 ). The building consists of four bays in the X direction and six bays in the Y direction.…”

Section: Description Of the Investigated Building And The Seismic Hmentioning

confidence: 99%

“…Step 4: The results of the assessments of structures in previous studies show that typical values of the overstrength reduction factor r s of multistorey reinforced concrete frame buildings designed according to Eurocodes 2 and 8 vary from around 2 to 3, whereas the values of ductility of the structure associated with the NC limit state μ NC vary from around 5 to 8. 39,59 Based on these boundary values, the overstrength reduction factor and ductility were estimated as r s = 2 and μ NC = 6, respectively. Note, that the ductility of the structure can also be estimated by the approach considered in the direct displacement-based design.…”

Section: Description Of the Investigated Building And The Seismic Hmentioning

confidence: 99%

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Formulation of risk‐targeted seismic action for the force‐based seismic design of structures

Žižmond

Dolšek

2019

Earthq Engng Struct Dyn

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Summary A risk‐targeted design spectral acceleration and the corresponding seismic design action for the force‐based design of structures is introduced by means of two formulations. The first one called direct formulation utilizes the seismic hazard function at the site of the structure. Because the seismic action defined in the codes is often associated with a designated return period, an indirect formulation is also introduced. It incorporates a risk‐targeted safety factor that can be used to define a risk‐targeted reduction factor. It is shown that the proposed formulations give analogical results and provide an insight into the concept of the reduction of seismic forces for the force‐based seismic design of structures if the objective is defined by a target collapse risk. The introduced closed‐form solution for the risk‐targeted reduction factor can be used to investigate how the target collapse risk, the seismic hazard parameters, the randomness of the seismic action, and the conventional parameters (ie, the overstrength factor and the deformation and energy dissipation capacity) affect the seismic design forces in the case of force‐based design. However, collaborative research is needed in order to develop appropriate models of these parameters. In the second part of the paper, the proposed formulations are demonstrated by estimating the risk‐targeted seismic design action for a six‐storey reinforced concrete building. By verifying the collapse risk of the designed structure, it is demonstrated that the risk‐targeted seismic action, in conjunction with a conventional force‐based design, provided structure with acceptable performance when measured in terms of collapse risk.

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“…The standard deviation was assumed to be equal to β Se,C = 0.40 . For this particular example, S e,C,a was estimated to amount to 1.69 g. S e,NC,a was then calculated by using (Equation ):

S_{e, italicNC, a} = \frac{S_{e, C, a}}{γ_{italicls}} = \frac{1.69 g}{1.15} = 1.47 g .

Section: Example: Estimation Of a Risk‐targeted Seismic Action Forcementioning

confidence: 99%

Section: Description Of the Investigated Building And The Seismic Hmentioning

confidence: 99%

Section: Description Of the Investigated Building And The Seismic Hmentioning

confidence: 99%

See 1 more Smart Citation

Formulation of risk‐targeted seismic action for the force‐based seismic design of structures

Žižmond

Dolšek

2019

Earthq Engng Struct Dyn

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“…Two site classes, namely, site classes C (denoted as FFC) and D (denoted as FFD), in accordance with the National Earthquake Hazards Reduction Program (NEHRP) classification, were studied in this research. Each of the two site classes contain 15 ground motion records as suggested by Sinković et al for the least number used in statistical seismic analysis. The far‐field records resulted from 10 different earthquake events with moment magnitude (M w ) ranging from 6.0 to 7.6.…”

Section: Capacity‐based Inelastic Displacement Spectramentioning

confidence: 99%

Capacity‐based inelastic displacement spectra for reinforced concrete bridge columns

Wang

Chang

2019

Earthq Engng Struct Dyn

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SUMMARY Capacity‐based inelastic displacement spectra that comprise an inelastic displacement ratio (CR) spectrum and the corresponding damage index (DI) spectrum are proposed in this study to aid seismic design and evaluation of reinforced concrete (RC) bridges. Nonlinear time history analyses of single‐degree‐of‐freedom (SDOF) systems are conducted using a versatile smooth hysteretic model when subjected to far‐field and near‐fault ground motions. It is demonstrated that the Park and Ang damage index can be a good indicator for assessing the actual visible damage condition of columns regardless of its loading history, providing a better insight into the seismic performance of bridges. The computed spectra for near‐fault (NF) ground motions show that as the magnitude of pulse period ranges increases from NF1 (0.5‐2.5 seconds) to NF2 (2.5‐5.5 seconds), the spectral ordinates of the CR and DI spectra increase moderately. In contrast, the computed spectra do not show much difference between NF2 and NF3 (5.5‐10.5 seconds) when the period of vibration Tn≤ 1.5 seconds, after which the spectral ordinates of NF3 tend to increase obviously, whereas those of NF2 decrease with increasing Tn. Moreover, when relative strength ratio R = 5.0, nearly all of the practical design scenarios could not survive NF3. On the basis of the computed spectra, CR and DI formulae are presented as a function of Tn, R, and various design parameters for far‐field and near‐fault ground motions. Finally, an application of the proposed spectra to the performance‐based seismic design of RC bridges is presented using DI as the performance objective.

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“…It is unlikely for one ground motion from the earthquake scenario contributing to the UHS at a period of interest to have as large spectral values as the UHS at all other periods [14]. Using the UHS as the target spectrum would be overly conservative to estimate responses to an earthquake scenario or develop a fragility function [15][16][17][18]. On the other hand, the CMS approach proposed by Baker [16] is attractive as it can yield a more realistic spectral shape of earthquakes.…”

Section: Introductionmentioning

confidence: 99%

Application of Conditional Mean Spectrum in Nonlinear Response History Analysis of Tall Buildings on Soft Soil

Khy¹,

Chintanapakdee²,

Wijeyewickrema³

2019

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The uniform hazard spectrum (UHS) and conditional mean spectrum (CMS) are commonly used as target spectra in selecting and scaling of records to be used in nonlinear response history analysis (NLRHA). When using CMS with tall buildings, CMS ground motions conditioned at multiple natural periods of the buildings should be considered. The application of CMS ground motions in NLRHA to estimate seismic demands for design of tall buildings located on soft-soil layers in Bangkok is investigated in this study. The seismic demands computed using multiple sets of CMS ground motions are compared with those computed using a single set of UHS spectral matching ground motions. Four existing tall buildings subjected to earthquake excitations in Bangkok were considered. The NLRHA was conducted using multiple sets of CMS ground motions, where periods of interest T  were considered at the periods closest to the periods of the first-three translational modes of the building in the direction of excitation. It was found that CMS ground motions conditioned at the higher-mode periods result in larger force demands than CMS ground motions conditioned at the fundamental period for some locations along the height of the building. The envelope of demands obtained by using multiple sets of CMS ground motions conditioned at different periods should be used in design but requires significant computational effort. Using UHS spectral matching ground motions can provide results close to such an envelope and reduce the computational effort significantly.

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Impact of the type of the target response spectrum for ground motion selection and of the number of ground motions on the pushover-based seismic performance assessment of buildings

Cited by 10 publications

References 25 publications

Formulation of risk‐targeted seismic action for the force‐based seismic design of structures

Formulation of risk‐targeted seismic action for the force‐based seismic design of structures

Capacity‐based inelastic displacement spectra for reinforced concrete bridge columns

Application of Conditional Mean Spectrum in Nonlinear Response History Analysis of Tall Buildings on Soft Soil

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