*About FHWA:
The Federal Highway Administration (FHWA) is an agency within the U.S. Department of Transportation that supports State and local governments in the design, construction, and maintenance of the Nation’s highway system (Federal Aid Highway Program) and various federally and tribal owned lands (Federal Lands Highway Program). Through financial and technical assistance to State and local governments, the Federal Highway Administration is responsible for ensuring that America’s roads and highways continue to be among the safest and most technologically sound in the world.
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There is an increasing trend towards recording marine seismic data directly on the seafloor.
This acquisition strategy is mainly motivated by the possibility to simultaneously measure
the three components of particle motion in addition to the pressure in the water column
immediately above the seabed. Such four-component (4C) seismic recordings thus allow
for the recording of S-waves in marine environments and offer the prospect of decomposing
the wavefield into its up- and down-going P- and S-wave constituents.
The assumptions for acquisition and processing of 4C data is today based on the ocean
bottom model as a welded acoustic-elastic contact at the seabed with a homogeneous
acoustic layer overlying a homogeneous elastic half-space. This may not hold in wide
areas of the oceans where the seafloor typically consists of soft, water-saturated sediments
characterized by having strong to very strong seismic attenuation. Moreover, cyclically
changing sedimentation processes lead to layering in the sediments, thus introducing
macroscopic seismic anisotropy, and overburden pressure and associated compaction effects
are likely to result in a strong velocity gradients.
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MECHANICAL BEHAVIOUR OF SLENDER RC WALL UNDER SEISMIC LOADING STRENGTHENED WITH EXTERNAL BONDED CFRP
Author: S. Qazi Ph-D student Université Lyon 1-INSA LYON ;L. Michel Associate Professor Université Lyon 1-INSA LYON;E. Ferrier Professor Université Lyon 1-INSA LYON 1 | Size: 0.8 MB | Format:PDF | Quality:Unspecified
Recent earthquake surveys have highlighted significance of RC walls as an integral part of
structures. It was observed that RC wall structures sustained less damage in comparison to
structures that did not possessed RC wall. Researchers on the basis of their post earthquake
surveys concluded that RC wall buildings sustained damage because of flaws in design and
construction work. In this article experimental result of six RC shear walls is discussed. They
were designed under-reinforced to fail in flexure. Four out of these six specimens were
strengthened externally with CFRP strips bonded to wall panel and mesh anchors installed at
wall foundation joint. Two specimens, one RC and one CFRP retrofitted, were subjected to
static load test and four specimens, one RC and three CFRP retrofitted, were subjected to
cyclic load tests. The test result analysis discussion includes cracking pattern, stiffness,
ultimate load capacity, ductility, and energy dissipation.
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The building foundations that may be subjected to seismic force should be designed so as to
maintain structural safety equivalent to or exceeding that of the upper structure. It is important
to conduct an investigation according to the state of the site with respect to possible ground
deformation such as liquefaction and landslide, and measures such as appropriate soil
improvement should be taken as needed.
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Clarifies the vital interdependence between structural steel design and fabrication drawings, equipping students to work flexibly with both. This book offers an overview of structural design theory. It provides examples, illustrations, and real-world assignments.
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Short explanation about SSI with case study presented by Dr. C.G. Shashkin & Dr. M.B. Lisyuk from Saint Petersburg State Transport University - NPO “Georeconstruction”, St. Petersburg
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Author: Donald O. Dusenberry | Size: 3.76 MB | Format:PDF | Quality:Unspecified | Publisher: JOHN WILEY & SONS, INC. | Year: 2010 | pages: 486
The need for protection against the effects of explosions is not new. The use of explosive weaponry by the military necessitated resistive entrenchments ages ago. Industrialization of our societies well over a century ago meant that we intended to manufacture, store, handle, and use explosives in constructive ways. To support these military and industrial purposes, a relatively small group of designers have worked to devise ways to strengthen the blast resistance of our structures.
Early attempts at blast-resistance design necessarily relied on judgment, test, and trial-and-error construction to fin the best solutions. As technology improved, designers became better able to predict the influence of explosions and the resistive responses that they strove to impart into their designs. More recently, in the past several decades chemists, physicists, blast consultants, and structural engineers have been empowered by technologies and computational tools that have enhanced the precision of their analyses and the efficien y of their designs.
At the same time, the need has increased. The small contingent of designers skilled in the art and science of creating structural designs that will resist explosive forces has been joined by a larger group of architects, engineers, blast consultants, and security consultants who are trying to respond to the increasing concern from a broader group of clients who fear an exposure that they did not anticipate before and frequently did not bring upon themselves. Consultants who have never before had to assess risks, devise risk-reduction programs, provide security systems, establish design-base threats, calculate the pressures and impulses from explosions, and create cost-effective structural designs are being thrust into the process. Many are ill-trained to respond. There are several good references on some of the aspects of designing for blast resistance. Some of these references support military purposes or for other reasons have government-imposed restrictions against dissemination. As such, they are not widely available to consultants working in the private sector. Nearly all those references and the references that are public each treat an aspect of blast phenomenology, security systems, and structural design for blast resistance, but few, if any, bring together in one place discussions of the breadth of the issues that are important for competent designs. Consultants are forced to collect a library of references and extract from each the salient information that they then synthesize into a comprehensive design approach.
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This paper presents the application of relation diagram method (RDM) to determine contribution of the parameters affected
on the blast induced ground vibration. There are two types of parameters: controllable and uncontrollable parameters. The study focused on controllable parameters. The more effective parameters for ground vibration at the point of interest are ground vibration in the point of blast (PPV in-blast) and geological structures. The more effective parameters for the ground vibration at the point of blast are explosive amount per delay, burden and stemming. If desired fragmentation is obtained from the blast, then geological structures should be modified by creating artificial discontinuities. If one desires to reduce the level of vibration in the point of blast,
then the following parameters should be modified ; explosive amount per delay, burden, stemming, and hole diameter.
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(AISC Video) Design Tips for Steel in Low or Moderate Seismic Regions - Dominic Kelly and Robert Tremblay
Size: 565 MB| Quality:VCD| Year:2009
This session will first provide design examples of different types of bracing systems for buildings whose seismic lateral forces were determined in Part One (An Introduction to Earthquake Engineering and Seismic Codes - Ductility) of this seminar. This session will then provide tips to structural engineers who design buildings in regions of low or moderate seismicity. The topics covered include determining site class and seismic design category, selecting a steel seismic-force-resisting system, and applying detailing requirements.
This seminar is presented by Dominic Kelly of Simpson Gupertz and Heger; and Robert Tremblay of Ecole Polytechnique.
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Dynamic Behaviour of Concrete Structures subjected to Blast and Fragment Impacts
Author: JOOSEF LEPPÄNEN | Size: 1.8 MB | Format:PDF | Quality:Unspecified | Publisher: Department of Structural Engineering Concrete Structures CHALMERS UNIVERSITY OF TECHNOLOGY Göteborg, Sweden 2002 | Year: 2002
For protective structures, reinforced concrete is commonly used. Concrete structures
subjected to explosive loading in a combination of blast and fragments will have very
different response than statically loaded structure. During the blast and the fragment
impacts the structure will shake and vibrate, severe crushing of concrete occurs and a
crater forms (spalling) in the front of the concrete; for large penetration, scabbing may
occur at the backside of the wall, or even perforation, with a risk of injury for people
inside the structure.
This thesis is intended to increase the knowledge of reinforced concrete structures
subjected to explosive loading, i.e. effects of blast and fragmentation. A further aim is
to describe and use the non-linear finite element (FE) method for concrete penetration
analyses. Particular attention is given to dynamic loading, where the concrete
behaviour differs compared to static loading. The compressive and tensile strengths
increase due to the strain rate effects. Initial stiffness increases, and moreover the
concrete strain capacity is increased in dynamic loading.
Traditionally, for prediction of the depth of penetration and crater formation from
fragments and projectiles, empirical relationships are used, which are discussed here
together with the effects of the blast wave that is caused by the explosion.
To learn more about the structural behaviour of concrete subjected to severe loading,
a powerful tool is to combine advanced non-linear FE analyses and experiments. A
trustworthy model must be able to capture correct results from several experiments,
including both the depth of penetration and the crater size. In this thesis, FE analyses
of concrete penetration with steel projectiles have been performed and compared to
existing experimental results. By using the non-linear FE program AUTODYN, the
depth of penetration and crater sizing can be predicted.
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