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Bozorgnia Y.,University of California at Berkeley | Hachem M.M.,Skidmore | Campbell K.W.,EQECAT Inc.
Earthquake Spectra | Year: 2010

This paper presents the process and fundamental results of a comprehensive ground motion prediction equation (GMPE, or "attenuation" relationship) developed for inelastic response spectra. We used over 3,100 horizontal ground motions recorded in 64 earthquakes with moment magnitudes ranging from 4.3-7.9 and rupture distances ranging from 0.1-199 km. For each record, we computed inelastic spectra for ductility ranging from one (elastic response) to eight. Our GMPE correlates inelastic spectral ordinates to earthquake magnitude, site-to-source distance, fault mechanism, local soil properties, and basin effects. The developed GMPE is used in both deterministic and probabilistic hazard analyses to directly generate inelastic - spectra. This is in contrast to developing "attenuation" relationships for elastic response spectra, carrying out a hazard analysis, and subsequently adopting approximate rules to derive inelastic response from elastic spectra. © 2010, Earthquake Engineering Research Institute.

Stromberg L.L.,University of Illinois at Urbana - Champaign | Beghini A.,Skidmore | Baker W.F.,Skidmore | Paulino G.H.,University of Illinois at Urbana - Champaign
Engineering Structures | Year: 2012

This paper describes an integrated topology optimization technique with concurrent use of both continuum four-node quadrilateral finite elements and discrete two-node beam elements to design structural braced frames that are part of the lateral system of a high-rise building. The work explores the analytical aspects of optimal geometry for braced frames to understand the underlying behavior and provides a theoretical benchmark to compare numerical results. The influence of the initial assumptions for the interaction between the quadrilaterals and the frame members are discussed. Numerical examples are given to illustrate the present technique on high-rise building structures. © 2011 Elsevier Ltd.

Sarkisian M.P.,Skidmore
Structure and Infrastructure Engineering | Year: 2016

Safety is the primary focus of structural design of buildings and infrastructures for expected operational life. However, with the growing importance of performance and the relationship of structures to the environment, additional considerations must be made to achieve successful design. These considerations must assess the structure’s impact on natural resources, long-term economic success and continuous operation following a significant abnormal loading event. Non-prescriptive approaches to design are becoming more important and perhaps will be common as we progress into the twenty-first century. These design approaches impart an improved understanding of behaviour, aides with economic predictions and increases efficiency of the building. Examples of non-prescriptive, performance-based approach to seismic design in both the United States and China will be presented as both regions represent major building markets utilising different methods for analysis and design. Specific building project examples will be described. © 2016 Informa UK Limited, trading as Taylor & Francis Group

Mazurek A.,Skidmore
Structural and Multidisciplinary Optimization | Year: 2012

In this paper, similarities between three-force and three-point non-smooth optimization problems are highlighted. Starting from geometrical rules controlling discrete optimum solutions for three-point problems a reasonable hypothesis is created for similar geometrical rules to control discrete optimum structures for three-force problems. The hypothesis is confirmed through a numerical approach. A step-by-step method to graphically obtain a discrete optimum structure for any set of three balanced forces is provided. It is shown that discrete optimum structures with large number of elements converge to the known continuum optimum solutions in the literature. © Springer-Verlag 2011.

Yin Y.-J.,Skidmore | Li Y.,Michigan Technological University
Engineering Structures | Year: 2011

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. © 2010 Elsevier Ltd.

A tubular building enclosure system with thermally-broken glass modules having evacuated air spaces assembled in rows and/or columns to form a structurally self-supporting, thermally insulating, and solar energy collecting facade.

Skidmore | Date: 2012-08-09

A tidal barrier is provided that may be selectively deployed in response to tidal changes. The tidal barrier includes a net having a tensile, membrane with an upper edge and a lower edge. The lower edge has a plurality of anchor points for affixing the lower edge to a seabed below a body of water. The tidal barrier further includes a bladder affixed to the upper edge and having a valve for selectively inflating and deflating the bladder. The bladder has a sufficient volume to cause the upper edge of the membrane to rise to a surface of the body of water when the volume is inflated with a gas. A pump is disposed in proximity to the tensile membrane and is in fluid communication with the valve of the bladder. The pump has a controller for selectively prompting the pump to inflate and deflate the bladder with the gas.

A tubular building enclosure system with thermally-broken modules having evacuated air spaces assembled in rows and/or columns to form a structurally self-supporting, thermally insulating, and solar energy collecting facade.

A tubular building enclosure system for unitized assembly in rows and columns to form a structurally self-supporting, thermally insulating, and solar energy collecting facade.

Tort C.,Skidmore | Hajjar J.F.,Northeastern University
Journal of Structural Engineering | Year: 2010

A computational study was conducted to investigate the nonlinear response of composite frames consisting of rectangular concrete-filled steel tube (RCFT) beam-columns and steel framing subjected to static and dynamic loads. Following mixed finite-element principles, a three-dimensional fiber-based beam finite-element model was developed, allowing slip deformation between steel tube and the concrete core. Comprehensive material constitutive relations were developed for the steel tube and the concrete core through examining the experimental results in the literature. The uniaxial stress-based steel and concrete constitutive relations include modeling of the effects of confinement, steel tube local buckling, cycling concrete into both tension and compression, cyclic softening, and other key cyclic phenomena observed for steel and concrete in RCFT members. The finite-element model was verified against a wide range of experimental tests under monotonic, quasistatic cyclic, and pseudodynamic loading conditions. The mixed finite-element model produced strong correlations with experimental results to simulate the nonlinear response of RCFT members with excellent computational efficiency. © 2010 ASCE.

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