Near -Source Pulse-Like Seismic Demand for Multi-Linear Backbone Oscillators

Baltzopoulos, Georgios; Vamvatsikos, Dimitrios; Iervolino, Iunio

doi:10.7712/120115.3476.704

Cited by 3 publications

(5 citation statements)

References 17 publications

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“…cases when H o was rejected) were encountered for T/T p ratios between 0.20 and 0.40. These hypothesis tests emphatically confirmed the premise already made in , that NS seismic demand is systematically different for oscillators with 0.10s < T ≤ 0.30s compared with that of SDOF systems with T > 0.30s. Less pronounced systematic differences were detected between low to moderate‐period oscillators and long to very‐long‐period oscillators, when T/T p < 0.50.…”

Section: Methodssupporting

confidence: 85%

“…This was demonstrated in for the case of single‐stripe pushover‐based simplified analysis using an earlier equation for NS‐FD inelastic spectra . More pertinent to the present model is the illustrative example included in , where a methodology for probabilistically incorporating T p into the calculation of NS inelastic demand at increasing levels of seismic intensity was demonstrated for a simple bilinear system. Extending that methodology into the realm of more complex multi‐linear backbones is a necessary next step that will permit the application of the model presented in this study towards performance‐based assessments in NS conditions.…”

Section: Discussion and Prospective Applicationsmentioning

confidence: 89%

“…Past investigations, where NS probabilistic seismic hazard analysis was implemented , showcased the fact that a NS design scenario will not be necessarily restricted to a single T p dominating NS structural response (elastic and inelastic). In fact, it was found in certain case‐studies that not only are different source to site configurations associated with different probability distributions of causal T p but that this is also true for a given site when increasing levels of seismic intensity are considered . It was also observed in those studies that at increasing IM levels, NS‐FD can become increasingly important for the determination of site‐specific mean inelastic demand.…”

Section: Discussion and Prospective Applicationsmentioning

confidence: 99%

“…The decision to base the model on the T/T p ratio was alluded to during the definition of pulse‐IDA curves. Nevertheless, in a preliminary version of the model by the same authors , a concern had already been raised about mixing the response of very low period oscillators with that of long‐period systems within a single T/T p cross section of data. In fact, in that work, it was suggested that at each T/T p ratio, responses from oscillators with natural period T ≤ 0.30s be omitted from the model.…”

Section: Methodsmentioning

confidence: 99%

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Analytical modelling of near‐source pulse‐like seismic demand for multi‐linear backbone oscillators

Baltzopoulos

Vamvatsikos

2016

Earthq Engng Struct Dyn

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Summary Nonlinear static procedures, which relate the seismic demand of a structure to that of an equivalent single‐degree‐of‐freedom oscillator, are well‐established tools in the performance‐based earthquake engineering paradigm. Initially, such procedures made recourse to inelastic spectra derived for simple elastic–plastic bilinear oscillators, but the request for demand estimates that delve deeper into the inelastic range, motivated investigating the seismic demand of oscillators with more complex backbone curves. Meanwhile, near‐source (NS) pulse‐like ground motions have been receiving increased attention, because they can induce a distinctive type of inelastic demand. Pulse‐like NS ground motions are usually the result of rupture directivity, where seismic waves generated at different points along the rupture front arrive at a site at the same time, leading to a double‐sided velocity pulse, which delivers most of the seismic energy. Recent research has led to a methodology for incorporating this NS effect in the implementation of nonlinear static procedures. Both of the previously mentioned lines of research motivate the present study on the ductility demands imposed by pulse‐like NS ground motions on oscillators that feature pinching hysteretic behaviour with trilinear backbone curves. Incremental dynamic analysis is used considering 130 pulse‐like‐identified ground motions. Median, 16% and 84% fractile incremental dynamic analysis curves are calculated and fitted by an analytical model. Least‐squares estimates are obtained for the model parameters, which importantly include pulse period Tp. The resulting equations effectively constitute an R − μ − T − Tp relation for pulse‐like NS motions. Potential applications of this result towards estimation of NS seismic demand are also briefly discussed. Copyright © 2016 John Wiley & Sons, Ltd.

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Section: Methodssupporting

confidence: 85%

Section: Discussion and Prospective Applicationsmentioning

confidence: 89%

Section: Discussion and Prospective Applicationsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Analytical modelling of near‐source pulse‐like seismic demand for multi‐linear backbone oscillators

Baltzopoulos

Vamvatsikos

2016

Earthq Engng Struct Dyn

Self Cite

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“…They pointed out that while setting the ductility demands being identical, the strength demands of SDOF systems subjected to near-fault ground motions are greater than those subjected to far-field ground motions. In order to predict the distinct type of inelastic demand caused by near-fault ground motions, Baltzopoulos et al (2016) proposed specific oscillators with trilinear backbone curves. In comparison with far-field ground motions, these researches (Alavi and Krawinkler, 2004; Baltzopoulos et al, 2016; Chopra and Chintanapakdee, 2001) consistently showed the distinct seismic demands of structures subjected to near-fault ground motions.…”

Section: Introductionmentioning

confidence: 99%

Simulation and analysis of a vertically irregular building subjected to near-fault ground motions

et al. 2020

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A shaking table test of a three-story reinforced concrete (RC) building was conducted. The tested building is vertically irregular because of the first story’s elevated height and the third story’s added RC walls. In addition to far-field ground motions, near-fault ground motions were exerted on this building. A numerical model of the three-story building was constructed. Comparing with the test results indicates that the numerical model is satisfactory for simulating the seismic response of the three-story building. This validated numerical model was then further applied to look into two issues: the effective section rigidities of RC members and the effects of near-fault ground motions. The study results show the magnitude of the possible discrepancy between the actual seismic response and the estimated seismic response, when the effective section rigidities of the RC members are treated as in common practice. An incremental dynamic analysis of the three-story RC building subjected to one far-field and one near-fault ground motion, denoted as CHY047 and TCU052, respectively, was conducted. In comparison with the far-field ground motion, the near-fault ground motion is more destructive to this building. In addition, the effect of the selected near-fault ground motion (i.e. TCU052) on the building’s collapse is clearly identified.

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Finding the design collapse capacity of a multi-story RC frame in near-fault based on the collapse risk by using the ratio method

Shanehsazzadeh,

Tehranizadeh,

Haj Najafi

2023

Numerical Methods in Civil Engineering

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The collapse risk role has increasingly drawn engineers' attention in the performance-based design field and engineers tend to design the structures in a way to be qualified enough to resist earthquakes, especially at near-fault sites. Due to specific characteristics of near-fault records, structures in near-fault required more collapse capacity in comparison with far-fault sites. Furthermore, it is necessary to determine the collapse capacity that structures should be designed to comply with standards and to meet the collapse risk limit in the given site. In this research, the ratio method is presented to determine the design collapse capacity of structures based on the risk value of 1% in 50 years as well as the site hazard stemming from the integration scenario for near-fault. In this method, the structure behavior and fundamental period are incorporated, and effect of pulse period is considered as well. This method utilizes the ratio of the collapse capacity of the structure in near-fault to that of far-fault named γ. Consequently, efficient procedures based on nonlinear static pushover are used for obtaining the collapse capacity in far-fault and near-fault. Then, the ratio method is employed on a midrise RC frame and the design collapse capacities are acquired for two amounts of Tp/T. The result shows ratio method can be used for any Tp/T values especially those corresponding to the governing Tp at site. Moreover, the least value of γ can be used conservatively since the design collapse capacity of the structure in near-fault is raised by reducing γ.

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Near -Source Pulse-Like Seismic Demand for Multi-Linear Backbone Oscillators

Abstract: Keywords: pushover, directivity, incremental dynamic analysis, performance based design. Abstract. Nonlinear static procedures, which relate the seismic demand of a structure to that of an equivalent single-degree-of-freedom (SDOF) oscillator

Cited by 3 publications

References 17 publications

Analytical modelling of near‐source pulse‐like seismic demand for multi‐linear backbone oscillators

Analytical modelling of near‐source pulse‐like seismic demand for multi‐linear backbone oscillators

Simulation and analysis of a vertically irregular building subjected to near-fault ground motions

Finding the design collapse capacity of a multi-story RC frame in near-fault based on the collapse risk by using the ratio method

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