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Muni Budhu "Foundations and Earth Retaining Structures", John Wiley & Sons, NY, 2007
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21st Century Security and CPTED: Designing for Critical Infrastructure Protection and Crime Prevention
21st Century Security and CPTED: Designing for Critical Infrastructure Protection and Crime Prevention
By Randall I. Atlas
Publisher: Auerbach Publications
Number Of Pages: 560
Publication Date: 2008-05-28
ISBN-10 / ASIN: 1420068075
ISBN-13 / EAN: 9781420068078
Binding: Hardcover
Product Description:
Offering one important answer to current concerns with violence and terrorism, this is the only book to examine current trends in the developing field of Crime Prevention through Environmental Design (CPTED). It includes contributions from the world's top CPTED practitioners. Highly relevant to critical infrastructure protection, the book addresses application of CPTED to high-security environments, as well as public and private sector buildings. Facilitating understanding across fields, it explains the architecture process to security directors, while explaining the security design process to architects. It serves as a practical guide for architects, security directors, law enforcement, Homeland Security professionals, building and property managers, as well as criminal justice, architecture, and security students.
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The report describes laboratory tests of arc welded T-joints between equal width rectangular
hollow sections. The brace and chord members were cold formed with a nominal yield stress
of 350 MPa. The welds were laid using MMAW and GMAW processes without profiling the
brace ends. The brace of each specimen was loaded in tension to failure with the chord
supported continuously so as not to induce significant bending effects.
The test results showed that the joint strength can be improved by using backing strips for the
butt welds, while backing rods (or filler rods) should not be used as they led to larger
variation in joint strengths, and often, inferior strengths. The test strengths are compared with
the design strengths obtained using the IIW Recommendations and Eurocode3, Part 1.8. It is
shown that for cold-formed tubes with a nominal yield stress of 350 MPa (or above), a design
check on the strength of the butt (or groove) weld is required in addition to the checks on the
strengths of the chord and brace members specified in the current design guidelines. An
equation is proposed for calculating the strength of the weld.
Keywords: butt weld, brace-to-chord connection, cold-formed steel, metal arc welding,
rectangular hollow section, T-joint design
28 pages
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I have some photos of space grid structures and I think that some engineers want to see them. Can I place them at this forum? If yes that in what section?
Here is the link to the design and detailing of a laboratory/office building by J. B. Higgins and B. R. Rogers MA, CEng, MICE according to B.s 8110 :
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This thesis is dedicated to developing a new structural concept which is rapidly
deployable and structurally effective. During the recent hundred years, various types of
spatial structural systems have been developed for different civil engineering and space
applications such as stadium cover, exhibition roof, communication boom, etc. Some
of these systems are structurally effective and thus have been used widely such as
double-layer space trusses. Some other types of spatial structures have been proposed
to be effective in construction time such as deployable structures. The structural
products developed in this research inherit both advantages of double-layer space
trusses and deployable structures in one system, which is named as Deployable
Tension-Strut Structure (DTSS).
Structural morphology of DTSSs is related to their mechanical features. The
morphology study shows geometric rules which is linked to deployability of the
structures and the locking mechanism. These geometric rules (shape grammar) serve as
a basis to develop an exhaustive design creation algorithm which is able to
automatically find numerous viable forms of DTSS. Although the algorithm is a
generative design tool, it is controllable in comparison with stochastic methods such as
genetic algorithm. The reason is shape grammar of DTSS is implemented from the
beginning of the design creation process.
Structural behaviour of the proposed DTSSs is investigated by advanced non-linear
structural analysis. The understanding of structural performance is a basis to deduce
the optimum design parameters of DTSS such as the span to depth ratio, and the
number of module in a span length. The newly proposed DTSS is also compared with
conventional double-layer space trusses by using a proposed Structural Efficiency
Index, which consider both self-weight and stiffness of the structure in the evaluation.
The result shows that DTSS is comparative to double layer space truss in terms of
structural efficiency.
Rapid deployment concept of DTSS is proved by prototyping and computer modeling.
The computer models show the possibility of deployment and the prototypes show that
the details of proposed joint system are suitable to accommodate deployability.
Experimental investigations show that the designed steel joints are stronger than the
structural steel members. The stiffness of joints allows folding of the structure
(removal) after full service load is applied. The tests show that service load level
causes insignificant deformation in the joints.
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EFFECT OF COMPOSITE ACTION ON THE DYNAMIC BEHAVIOUR OF SPACE STRUCTURES
In this work, the effect of introducing composite action in changing the dynamic
characteristics of space frames, in particular the natural frequencies and damping ratios
was presented. The study was expanded to determine the effect of composite action in
changing the response to dynamic excitations. The measured responses included the
lateral displacements and changes in the internal member force distribution under
shaking table vibrations.
Three aluminium space frame models of the square on square (SOS) configuration were
manufactured. The first model was non-composite, while composite action was applied
to the other two models with a top aluminium deck and a timber deck, respectively.
Two common cases of support conditions were used in connecting the models to the
loading frame, which was the platform of the shaking table.
Initial displacement method (snap test) was used to determine the frequency of vibration
and the damping ratio of test models in the vertical and horizontal directions using
logarithmic decrement method. All models were then exposed to shaking table
vibrations to determine the changes in dynamic responses between different models.
These tests were repeated for the three models after the successive removal of panels
from one direction to identify the changes to their characteristics and behaviour with
different aspect ratios.
The second part of the study was carried out numerically by using the finite element
package ABAQUS. It started by selecting a valid finite element model from nine
proposed models using experimental test results on physical structures. A parametric
study was conducted using the validated finite element model to expand the study to
include two common space frame configurations; the square on large square (SOLS)
and square on diagonal (SOD), and two other cases of support configurations, namely,
fully edge-supported and supports at corners and middle edges of models.
Based on the work done in this study, it can be concluded that composite action
changed the dynamic characteristics of space frames, which was clear in the increase of
their vibration frequencies in all directions as a result of the increase in stiffness.
Furthermore, the increase in stiffness resulted in a general reduction in the damping
ratio of space frames covered with aluminium deck, while the high friction with top
joints and the nature of timber as a good energy absorbent material resulted in a variable
effect on the damping ratio associated with the increase in aspect ratio.
The effect of composite action was clear in reducing the lateral displacement of
composite models by more than 50% compared to the non-composite case. Moreover,
composite action resulted in changing the distribution of internal forces in diagonal and
lower chord members such that forces became more concentrated at corners and edges
parallel to the direction
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Thin-walled members, by their very nature, have the potential to suffer from a variety of cross-section stability problems. CUFSM employs the semi-analytical finite strip method to provide solutions for the cross-section stability of such members. The software has been successfully used by researchers, educators, students, and practicing engineers. While CUFSM is most commonly used for thin-walled cold-formed steel members, it has also been used for a large variety of other materials and applications.
Design of Cold-Formed Steel Members Using the Direct Strength Method
As approved July 2003 by the American Iron and Steel Institute Committee on Specifications and finalized January 2004. App. 1 of the North American Spec. for the Design of Cold-Formed Steel Structural Members:
Specification January 2004 version
Commentary January 2004 version
Note, improvements continue to be made and are now continually made available in future editions of the North American Specification. Currently AISI-S100-07 contains the latest Specification approved procedures for the Direct Strength Method. In 2010 a DSM method for inelastic bending reserve was approved.
Direct Strength Method for CFS Design
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CUFSM version 3.12, free for use, including souce code in Matlab:
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Design of Cold-Formed Steel Members Using the Direct Strength Method:
Specification (pdf) January 2004 version:
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