The Experts below are selected from a list of 44976 Experts worldwide ranked by ideXlab platform
Yuejun Yin - One of the best experts on this subject based on the ideXlab platform.
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loss estimation of light frame Wood Construction subjected to mainshock aftershock sequences
2011Co-Authors: Yuejun YinAbstract:Aftershocks occur following an earthquake of large magnitude (referred to as the mainshock) and cause further damage to buildings that may have sustained damage in the mainshock. In this paper, an object-oriented framework is proposed to estimate seismic losses of light-frame Wood buildings subjected to mainshock and aftershock sequences. Mainshocks are simulated as a homogeneous Poisson process, whereas aftershocks are simulated as a nonhomogeneous Poisson process. Back-to-back mainshock-aftershock nonlinear dynamic analysis is performed to determine the maximum interstory drift attributable to each earthquake occurrence (either mainshock or aftershock). Seismic risk is quantified in terms of economic losses in this paper. The damage loss (transition cost) and downtime cost are included in the loss estimation, considering a time-discount factor. Last, the proposed framework is demonstrated by an example that examines the seismic loss of typical light-frame Wood residential buildings in the United States....
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probabilistic loss assessment of light frame Wood Construction subjected to combined seismic and snow loads
2011Co-Authors: Yuejun YinAbstract:In some areas, e.g., mountainous areas in the western United States, both seismic and snow loads are significant. Limited research has been conducted to investigate the seismic risk of light-frame Wood Construction in those areas considering the combined loads, particularly the snow accumulation. An object-oriented framework of the risk assessment for light-frame Wood Construction subjected to combined seismic and snow hazards is proposed in this paper. A typical one-story light-frame Wood residential building is selected to demonstrate the proposed framework. Economic losses of the building due to the combined hazards are evaluated using the proposed framework. It is found that in areas with significant snow accumulation, the snow load has significant effects on the seismic risk assessment for light-frame Wood Construction.
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uniform hazard versus uniform risk bases for performance based earthquake engineering of light frame Wood Construction
2010Co-Authors: Yuejun Yin, Bruce R. Ellingwood, William M. BulleitAbstract:This paper investigates the implications of designing for uniform hazard versus uniform risk for light-frame Wood residential Construction subjected to earthquakes in the United States. Using simple structural models of one-story residences with typical lateral force-resisting systems (shear walls) found in buildings in western, eastern and central regions of the United States as illustrations, the seismic demands are determined using nonlinear dynamic time-history analyses, whereas the collapse capacities are determined using incremental dynamic analyses. The probabilities of collapse, conditioned on the occurrence of the maximum considered earthquakes and design earthquakes stipulated in ASCE Standard 7-05, and the collapse margins of these typical residential structures are compared for typical Construction practices in different regions in the United States. The calculated collapse inter-story drifts are compared with the limits stipulated in FEMA 356/ASCE Standard 41-06 and observed in the recent experimental testing. The results of this study provide insights into residential building risk assessment and the relation between building seismic performance implied by the current earthquake-resistant design and Construction practices and performance levels in performance-based engineering of light-frame Wood Construction being considered by the SEI/ASCE committee on reliability-based design of Wood structures. Further code developments are necessary to achieve the goal of uniform risk in earthquake-resistant residential Construction. Copyright © 2010 John Wiley & Sons, Ltd.
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seismic collapse risk of light frame Wood Construction considering aleatoric and epistemic uncertainties
2010Co-Authors: Yuejun YinAbstract:Collapse of light-frame Wood buildings in earthquakes causes casualties and economic losses. The collapse risk of buildings under seismic loads are uncertain because of aleatoric and epistemic uncertainties in both ‘demand’ and ‘capacity’. Both sources of uncertainties are considered in this study to investigate their effects on the collapse risk of Wood structures due to seismic loads. Record-to-record uncertainty and effect of spectral shape (e) of ground motion records are examined. Uncertainties in structural resistance are represented in typical Wood-frame shear walls, which are modeled by a hysteresis model with 10 parameters, each of which is treated as a random variable. Epistemic uncertainty that is introduced by the modeling process is examined in this study. The implications of inclusion of all sources of uncertainties on collapse risk are investigated and discussed in the context of comparing with the collapse risk in concrete and steel structures. It is found that the resistance uncertainty as well as modeling uncertainty have significant impacts on the seismic collapse risk of light-frame Wood buildings. Some previous studies that neglected the effect of resistance uncertainty in seismic performance evaluation may lead to unconservative results.
William M. Bulleit - One of the best experts on this subject based on the ideXlab platform.
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uniform hazard versus uniform risk bases for performance based earthquake engineering of light frame Wood Construction
2010Co-Authors: Yuejun Yin, Bruce R. Ellingwood, William M. BulleitAbstract:This paper investigates the implications of designing for uniform hazard versus uniform risk for light-frame Wood residential Construction subjected to earthquakes in the United States. Using simple structural models of one-story residences with typical lateral force-resisting systems (shear walls) found in buildings in western, eastern and central regions of the United States as illustrations, the seismic demands are determined using nonlinear dynamic time-history analyses, whereas the collapse capacities are determined using incremental dynamic analyses. The probabilities of collapse, conditioned on the occurrence of the maximum considered earthquakes and design earthquakes stipulated in ASCE Standard 7-05, and the collapse margins of these typical residential structures are compared for typical Construction practices in different regions in the United States. The calculated collapse inter-story drifts are compared with the limits stipulated in FEMA 356/ASCE Standard 41-06 and observed in the recent experimental testing. The results of this study provide insights into residential building risk assessment and the relation between building seismic performance implied by the current earthquake-resistant design and Construction practices and performance levels in performance-based engineering of light-frame Wood Construction being considered by the SEI/ASCE committee on reliability-based design of Wood structures. Further code developments are necessary to achieve the goal of uniform risk in earthquake-resistant residential Construction. Copyright © 2010 John Wiley & Sons, Ltd.
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new yield model for Wood dowel connections
2010Co-Authors: Joseph F Miller, William M. Bulleit, Richard J SchmidtAbstract:The current National Design Specification (NDS) for Wood Construction design methods for dowel-type connectors are based on four-yield modes for connections in double shear. These yield modes were formulated for use with steel dowels as fasteners. Hence design with nonferrous fasteners, such as Wood pegs, common in timber frame joinery, is not addressed. Wood pegs, while large in diameter, are considerably more flexible than steel dowels of the same size. A fifth failure mode is proposed for use with Wood pegs. This new failure mode, called Mode V yielding, which is an effective cross-grain dowel failure, has been observed in physical testing as well as numerical modeling. The objective of this paper is to establish a design procedure for the Mode V yielding of pegs. The procedure is calibrated to the level of performance (reliability) expected from the other yield modes. A regression equation to relate the effective cross-grain yield capacity of pegs to specific gravity is also developed for use with the Mode V design equation. A reliability analysis indicates that the proposed Mode V design equation can be used in conjunction with existing NDS yield equations for design of Wood doweled connections.
Bruce R. Ellingwood - One of the best experts on this subject based on the ideXlab platform.
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uniform hazard versus uniform risk bases for performance based earthquake engineering of light frame Wood Construction
2010Co-Authors: Yuejun Yin, Bruce R. Ellingwood, William M. BulleitAbstract:This paper investigates the implications of designing for uniform hazard versus uniform risk for light-frame Wood residential Construction subjected to earthquakes in the United States. Using simple structural models of one-story residences with typical lateral force-resisting systems (shear walls) found in buildings in western, eastern and central regions of the United States as illustrations, the seismic demands are determined using nonlinear dynamic time-history analyses, whereas the collapse capacities are determined using incremental dynamic analyses. The probabilities of collapse, conditioned on the occurrence of the maximum considered earthquakes and design earthquakes stipulated in ASCE Standard 7-05, and the collapse margins of these typical residential structures are compared for typical Construction practices in different regions in the United States. The calculated collapse inter-story drifts are compared with the limits stipulated in FEMA 356/ASCE Standard 41-06 and observed in the recent experimental testing. The results of this study provide insights into residential building risk assessment and the relation between building seismic performance implied by the current earthquake-resistant design and Construction practices and performance levels in performance-based engineering of light-frame Wood Construction being considered by the SEI/ASCE committee on reliability-based design of Wood structures. Further code developments are necessary to achieve the goal of uniform risk in earthquake-resistant residential Construction. Copyright © 2010 John Wiley & Sons, Ltd.
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Performance of Light-Frame Wood Residential Construction Subjected to Earthquakes in Regions of Moderate Seismicity
2008Co-Authors: Bruce R. Ellingwood, David V Rosowsky, Weichiang PangAbstract:The majority of single-family dwellings in the United States are light-frame Wood Construction. Residential Construction practices have evolved gradually over the years, most light-frame Wood structures have not been structurally engineered, and many residential buildings suffered significant damage in recent hurricane and earthquake disasters. As a result, new concepts and methodologies are evolving to better predict and evaluate the performance of Wood frame structures exposed to natural hazards and to support improved residential building practices. This paper examines the behavior of typical light-frame Wood structural systems in the central and eastern United States under earthquake hazards. Nonlinear structural analysis tools and stochastic methods are used to model the uncertainties in ground motion intensity and structural response. Fragility curves defining damage state probabilities as a function of ground motion intensity are developed for typical lateral force-resisting shear wall systems subjected to increasing levels of ground motion. A comparison of these fragilities with those embedded in HAZUS provides additional perspective on damage potential for residential Construction in regions of low-to-moderate seismicity.
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fragility assessment of light frame Wood Construction subjected to wind and earthquake hazards
2004Co-Authors: Bruce R. Ellingwood, David V Rosowsky, Jun Hee KimAbstract:A fragility analysis methodology is developed for assessing the response of light-frame Wood Construction exposed to stipulated extreme windstorms and earthquakes. Performance goals and limit states (structural and nonstructural) are identified from a review of the performance of residential Construction during recent hurricanes and earthquakes in the United States. Advanced numerical modeling tools provide a computational platform for risk analysis of light-frame Wood building structural systems. The analysis is demonstrated for selected common building configurations and Construction (defined, e.g., by roof sheathing, truss spacing, and roof or shear wall nailing patterns). Limit state probabilities of structural systems for the performance levels identified above are developed as a function of 3-s gust wind speed (hurricanes) and spectral acceleration (earthquakes), leading to a relation between limit state probabilities and the hazard stipulated in ASCE Standard 7, “Minimum design loads for buildings ...
Jun Hee Kim - One of the best experts on this subject based on the ideXlab platform.
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fragility assessment of light frame Wood Construction subjected to wind and earthquake hazards
2004Co-Authors: Bruce R. Ellingwood, David V Rosowsky, Jun Hee KimAbstract:A fragility analysis methodology is developed for assessing the response of light-frame Wood Construction exposed to stipulated extreme windstorms and earthquakes. Performance goals and limit states (structural and nonstructural) are identified from a review of the performance of residential Construction during recent hurricanes and earthquakes in the United States. Advanced numerical modeling tools provide a computational platform for risk analysis of light-frame Wood building structural systems. The analysis is demonstrated for selected common building configurations and Construction (defined, e.g., by roof sheathing, truss spacing, and roof or shear wall nailing patterns). Limit state probabilities of structural systems for the performance levels identified above are developed as a function of 3-s gust wind speed (hurricanes) and spectral acceleration (earthquakes), leading to a relation between limit state probabilities and the hazard stipulated in ASCE Standard 7, “Minimum design loads for buildings ...
Manuele Margni - One of the best experts on this subject based on the ideXlab platform.
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forestry carbon budget models to improve biogenic carbon accounting in life cycle assessment
2019Co-Authors: Marieke Head, Annie Levasseur, Robert Beauregard, Pierre Y. Bernier, Manuele MargniAbstract:Abstract Currently, Wood and Wood Construction materials have limitations in how carbon fluxes are accounted for in life cycle assessments. The biogenic carbon balance of Wood is often considered to be neutral, meaning that the carbon sequestered by biomass through photosynthesis is considered equal to the carbon feedstock in Wood that is eventually released throughout its life cycle. Several publications have recently shown that this assumption could lead to accounting errors. This research work aims to improve the biogenic carbon accounting of the forestry phase of the life cycle of softWood products. This involved specifically modelling carbon fluxes as a function of tree species, growing conditions and forest management practices, from Canadian managed forests. A baseline natural forest scenario was run for 1000 years until the carbon stocks were assumed to reach an approximate steady-state, followed immediately by a harvest scenario that was simulated for another 100 years. The ecosystem carbon costs of the harvest activity were calculated for 117 species and region forest landscapes across Canada and expressed per cubic meter of harvested Wood. Most landscapes showed net sequestration after 100 years of harvest history. Exceptions to this included outlier landscapes characterized by low average annual temperatures and precipitation where slightly positive values (net emissions) were found. The mean time to ecosystem cost neutrality for each species ranged from 16 to 60 years. Knowing the time since forest management has started on a particular forest landscape now enables managers to obtain an estimate of ecosystem carbon cost per cubic meter of Wood harvested for most of Canada's forests and commercial tree species. These ecosystem carbon costs can be used to generate regionalized cradle-to-gate life cycle inventories for harvested Wood products across Canada.
