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Evaluation of Building Resilience Under Earthquake Input Using Single, Double and Multiple Impulses

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889452705 Year: Pages: 61 DOI: 10.3389/978-2-88945-270-5 Language: English
Publisher: Frontiers Media SA
Subject: General and Civil Engineering --- Environmental Engineering
Added to DOAB on : 2018-11-16 17:17:57
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This eBook is the third in a series of books on the critical earthquake response of elastic or elastic-plastic structures under near-fault or long-duration ground motions, and includes four original research papers which were published in the specialty section Earthquake Engineering in ‘Frontiers in Built Environment’. Several extensions of the first eBook and the second eBook are included here. The first article is on the earthquake resilience of residential houses after repeated ground motions with high intensity. The 2016 Kumamoto earthquake brought a significant impact on the earthquake resilience of residential houses under repeated ground motions with high intensity in a few days. The necessary strength upgrade withstanding two repeated high-intensity ground motions was found to be 1.5. The second article is concerned with the smart enhancement of earthquake resilience of building structures under both near-fault and long-duration ground motions. A hybrid system of base-isolation and building connection control was proposed and its earthquake resilience to near-fault and long-duration ground motions was evaluated by a double impulse and a multiple impulse. It was demonstrated that the base-isolation is effective for near-fault ground motions and the building connection system using passive dampers is effective for long-duration ground motions. The third article is related to the robustness evaluation of elastic-plastic base-isolated high-rise buildings under resonant near-fault ground motions. The robustness function was introduced to evaluate quantitatively the robustness of elastic-plastic base-isolated high-rise buildings. The fourth article is an extension of the previously proposed energy balance approach to a bilinear elastic-plastic single-degree-of-freedom system under a long-duration sinusoidal ground motion. A historical difficulty in nonlinear vibration posed by Caughey (1960) and Iwan (1961) has been overcome in a smart manner after half a century. The approach presented in this eBook, together with the previous eBooks, is an epoch-making accomplishment to open the door for simpler and deeper understanding of structural reliability and resilience of built environments in the elastic-plastic and nonlinear range.

Critical Earthquake Response of Elastic-Plastic Structures and Rigid Blocks under Near-Fault Ground Motions: Closed-Form Approach via Double Impulse

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Book Series: Frontiers Theme Book ISBN: 9782889198702 Year: Pages: 64 DOI: 10.3389/978-2-88919-870-2 Language: English
Publisher: Frontiers Media SA
Subject: General and Civil Engineering --- Environmental Engineering
Added to DOAB on : 2016-01-19 14:05:46
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This eBook is the second in a series of books on the critical earthquake response of elastic-plastic structures or rigid blocks under near-fault ground motions, and includes four original research papers which were published in the specialty section Earthquake Engineering in ‘Frontiers in Built Environment’. Several extensions of the first book1 are included here. The first article is on the soil-structure interaction problem. The reduction of an original soil-structure interaction model into a single-degree-of-freedom (SDOF) model enables the application of the original theory for an SDOF model to such complicated soil-structure interaction model. The second article is concerned with the extension of the original theory for an SDOF model to a 2DOF model. Since the simple application of the original theory for an SDOF model to a multi-degree-of-freedom model is difficult due to out-of-phase phenomenon of multiple masses, a convex model theory is introduced and an upper bound of elastic-plastic response is derived. The third article is related to the stability problem of structures (collapse problems of structures) in which the P-delta effect is included. It is shown that the original theory for an SDOF model with elastic-perfectly plastic restoring-force characteristic can be applied to a model with negative second slope. The fourth article is an application of the energy balance approach to an overturning limit problem of rigid blocks. A closed-form expression of the overturning limit of rigid blocks is derived for the first time after the Housner’s pioneering work in 1963. The approach presented in this book, together with the first book, is an epoch-making accomplishment to open the door for simpler and deeper understanding of structural reliability of built environments in the elastic-plastic and nonlinear range.

Critical Earthquake Response of Elastic-Plastic Structures Under Near-Fault Ground Motions: Closed-Form Approach via Impulse Input

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ISBN: 9782889197422 Year: Pages: 55 DOI: 10.3389/978-2-88919-742-2 Language: English
Publisher: Frontiers Media SA
Subject: General and Civil Engineering
Added to DOAB on : 2017-08-30 10:14:31
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The specialty section Earthquake Engineering is one branch of Frontiers in Built Environment and welcomes critical and in-depth submissions on earthquake ground motions and their effects on buildings and infrastructures. Manuscripts should yield new insights and ultimately contribute to a safer and more reliable design of building structures and infrastructures. The scope includes the characterization of earthquake ground motions (e.g. near-fault, far-fault, short-period, long-period), their underlying properties, their intrinsic relationship with structural responses, and the true behaviors of building structures and infrastructures under risky and uncertain ground motions. More specific topics include recorded ground motions, generated ground motions, response spectra, stochastic modeling of ground motion, critical excitation, geotechnical aspects, soil mechanics, soil liquefaction, soil-structure interactions, pile foundations, earthquake input energy, structural control, passive control, active control, base-isolation, steel structures, reinforced concrete structures, wood structures, building retrofit, structural optimization, uncertainty analysis, robustness analysis, and redundancy analysis. This eBook includes four original research papers, in addition to the Specialty Grand Challenge article, on the critical earthquake response of elastic-plastic structures under near-fault or long-duration ground motions which were published in the specialty section Earthquake Engineering. In the early stage of dynamic nonlinear response analysis of structures around 1960s, a simple hysteretic structural model and a simple sinusoidal earthquake ground motion input were dealt with together with random inputs. The steady-state response was tackled by an equivalent linearization method developed by Caughey, Iwan and others. In fact, the resonance plays a key role in the earthquake-resistant design and it has a strong effect even in case of near-fault ground motions. In order to draw the steady-state response curve and investigate the resonant property, two kinds of repetition have to be introduced. One is a cycle, for one forced input frequency, of the initial guess of the steady-state response amplitude, the construction of the equivalent linear model, the analysis of the steady-state response amplitude using the equivalent linear model and the update of the equivalent linear model based on the computed steady-state response amplitude. The other is the sweeping over a range of forced input frequencies. This process is quite tedious. Four original research papers included in this eBook propose a new approach to overcome this difficulty. Kojima and Takewaki demonstrated that the elastic-plastic response as continuation of free-vibrations under impulse input can be derived in a closed form by a sophisticated energy approach without solving directly the equations of motion as differential equations. While, as pointed out above, the approach based on the equivalent linearization method requires the repetition of application of the linearized equations, the method by Kojima and Takewaki does not need any repetition. The double impulse, triple impulse and multiple impulses enable us to describe directly the critical timing of impulses (resonant frequency) which is not easy for the sinusoidal and other inputs without a repetitive procedure. It is important to note that, while most of the previous methods employ the equivalent linearization of the structural model with the input unchanged, the method treated in this eBook transforms the input into a series of impulses with the structural model unchanged. This characteristic guarantees high accuracy and reliability even in the large plastic deformation range. The approach presented in this eBook is an epoch-making accomplishment to open the door for simpler and deeper understanding of structural reliability of built environments in the elastic-plastic range.

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