The American Society for Testing and Materials (ASTM) is an independent organization devoted to the development of standards.

American Society for Testing and Materials

「脆弱性(Vulnerability)」とは何か

Social Vulnerability to Environmental Hazards

Minimum Design Loads for Buildings and Other Structures provides requirements for general structural design and includes means for determining dead, live, soil, flood, wind, snow, rain, atmospheric ice, and earthquake loads, as well as their combinations, which are suitable for inclusion in building codes and other documents. This Standard, a revision of ASCE/SEI 7-05, offers a complete update and reorganization of the wind load provisions, expanding them from one chapter into six. The Standard contains new ultimate event wind maps with corresponding reductions in load factors, so that the loads are not affected, and updates the seismic loads with new risk-targeted seismic maps. The snow, live, and atmospheric icing provisions are updated as well. In addition, the Standard includes a detailed Commentary with explanatory and supplementary information designed to assist building code committees and regulatory authorities. Standard ASCE/SEI 7 is an integral part of building codes in the United States. Many of the load provisions are substantially adopted by reference in the International Building Code and the NFPA 5000 Building Construction and Safety Code. Structural engineers, architects, and those engaged in preparing and administering local building codes will find this Standard an essential reference in their practice. Note: New orders are fulfilled from the second printing, which incorporates the errata to the first printing.

Minimum Design Loads for Buildings and Other Structures

Trees, and their derivative products, have been used by societies around the world for thousands of years. Contemporary construction of tall buildings from timber, in whole or in part, suggests a growing interest in the potential for building with wood at a scale not previously attainable. As wood is the only significant building material that is grown, we have a natural inclination that building in wood is good for the environment. But under what conditions is this really the case? The environmental benefits of using timber are not straightforward; although it is a natural product, a large amount of energy is used to dry and process it. Much of this can come from the biomass of the tree itself, but that requires investment in plant, which is not always possible in an industry that is widely distributed among many small producers. And what should we build with wood? Are skyscrapers in timber a good use of this natural resource, or are there other aspects of civil and structural engineering, or large-scale infrastructure, that would be a better use of wood? Here, we consider a holistic picture ranging in scale from the science of the cell wall to the engineering and global policies that could maximise forestry and timber construction as a boon to both people and the planet.

The wood from the trees: The use of timber in construction

Soft-story woodframe buildings are recognizable by their large garage openings at the bottom story which are typically for parking and storage. In soft-story buildings the relative stiffness and strength of the soft-story, usually the bottom story, is significantly less than the upper stories due to the presence of large openings which reduce the available space for lateral force resisting system components such as shearwalls. This leads to large interstory drifts and potential collapse at the ground floor, before the upper stories inter-story experience significant drifts. In many cases the ground floor eccentricity, the distance between the center of rigidity and center of mass, of the soft-story is significant enough to develop considerable in-plane torsional moment in addition to the lateral force caused by the earthquake. A Performance Based Seismic Retrofit (PBSR) procedure can be used to effectively design retrofits that improve the performance of these at-risk buildings. This paper focuses on the PBSR methodology and the application and validation of this retrofit technique to a 4,000 sq. ft. full-scale four-story woodframe building tested at the University of California San Diego (UCSD) Network for Earthquake Engineering Simulation (NEES) outdoor shake table. The structure was retrofitted with various systems including a system that combined wood structural panel sheathing and Simpson Strong-Tie ® Strong Frame ® steel special moment frames. These types of retrofit techniques improve the performance of the soft-story building while accommodating existing architectural constraints of the building.

Performance-Based Seismic Retrofit of Soft-Story Woodframe Buildings

This paper presents a qualitative evaluation of uni-axial shake table test results for a halfscale reinforced concrete house designed by the Indonesia Aid Foundation (IAF). The building is intended to provide a quality-controlled design by being precast at a factory and delivered to the site for assembly, thus providing a living area for a family of approximately six people. In addition, the house is to be base isolated on used car tires filled with sand to approximate more technical rubber bearing base isolators available for use in construction and seismic retrofit today. The base isolation system was extremely effective and did not allow shear force to be transferred into the reinforced concrete walls, resulting in virtually no damage.

http://www.sid.ir/en/VEWSSID/J_pdf/103820080106.pdf

Shake table test results for a half-scale reinforced concrete indonesian house with and without economical base isolation

https://www.fpl.fs.fed.us/documnts/pdf2014/fpl_2014_lindt002.pdf

Seismic Risk Reduction for Soft-Story Wood-Frame Buildings: Test Results and Retrofit Recommendations from the Nees-Soft Project

Hurricanes generate elevated surge levels and strong waves that can cause extensive damage to buildings and other coastal infrastructure, especially those located in low-lying coastal regions. The history of recorded damage on buildings near the shoreline from past storms indicates that the intensity of storms and resulting damage has increased over the past 30 years (Emanuel, 2005). For example, the United States has been impacted by recent events such as Hurricanes Katrina (2005), Ike (2008), Sandy (2012), and Harvey (2017). Computational Fluid Dynamics (CFD) models have been widely developed and applied to estimate the wave pressure and forces; advances in recent years have been supported by an increase in computation power, which allows more detailed calculations of the complex hydrodynamics associated with wave action. The performance of CFD models must be validated or verified through detailed comparisons with benchmark tests (e.g. analytic solutions or physical experiments).

/pdf/numerical-modeling-of-non-breaking-impulsive-breaking-and-3a1l5g6j4t.pdf

Numerical modeling of non-breaking, impulsive breaking, and broken wave interaction with elevated coastal structures

High mast lighting structures are being increasingly used to provide illumination for large intersections, particularly for highways located in rural areas. These structures, ranging from approximately 50 – 130 ft (15 – 40 m) in height, are exposed to high wind forces that in turn produce a tremendous number of loading cycles each year. A recent high mast lighting structural support failure in the high plains of Colorado near Denver International Airport served as the impetus for this study. Specifically, a numerical investigation to determine the nature of the complex dynamic response, estimate the fatigue life, and develop a prescriptive reliability-based selection (design) procedure for high-mast lighting structural supports. Morison’s equation, which provides relative force for slender bodies as a function of flow velocity, was applied within a dynamic finite element framework in order to account for the relative motion between the wind and the motion of the structure. Then, a well-known random vibrations approach was coupled with Miner’s rule to estimate the fatigue life of the structural support. Six different design parameters as well as mean wind velocities were examined.

John W. van de Lindt

Papers

Performance-Based Seismic Retrofit of Soft-Story Woodframe Buildings

Shake table test results for a half-scale reinforced concrete indonesian house with and without economical base isolation

Seismic Risk Reduction for Soft-Story Wood-Frame Buildings: Test Results and Retrofit Recommendations from the Nees-Soft Project

Numerical modeling of non-breaking, impulsive breaking, and broken wave interaction with elevated coastal structures

Development of a Reliability-Based Design Procedure for High-Mast Lighting Structural Supports