الفهرس 
LITERATURE REVlEWOnly 14 pages are availabe for public view
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Abstract
The design and construction of steel transmission towers has been
developed over the past century from the simple use of wind mill towers
modified to carry wires, to towers having large heights and spans. tr is a
common practice to use steel angle cross-sections for the tower main legs
and web members. Angles are advantageous due to the simplicity of
bolting members directly together without the use of gusset plates.
Simplified fabrication and erection procedures help to reduce overall
structure cost. Hot-rolled steel angle sections have been used extensively
for that purpose for several decades.
However, as cold-formed sections have become more popular in
steel constructions, their application in case of transmission towers is also
increasing, especially in case of small size angles. Due to the f1exibility
of their forming process, using cold-formed sections give several
advantages such as the ability to produce a wide range of angle section
shapes to suit individual project requirements; for example lipped and
60° angles.
Cold-forming can be used to provide stiffening lips to prevent
local buckling of thin, wide elements, to optimize shapes so that longer
unbraced lengths can be used. As a result. cost saving can be realized
through reductions in the required weight of steel. Although the lips are
beneficial in improving resistance to damage in shipping and handling, it
has the disadvantage of preventing the nesting of sections which requires
more volume in shipping. The .ips also make connections to the inside of
the leg difficult compared to a plain angle.
The use of 60° angles as main legs is highly suitable for the case
of triangular towers. Their use in this case allows dispensing with the
need of gusset plates, since the bracing members intersecting at 60° can
be bolted directly to the legs. They have the advantage of an increased
f1exural buckling strength, but have the disadvantage of a reduced
torsional-flexural buckling strength. In this research. a numerical procedure using the finite element
technique is presented to investigate both local and overall buckling of
axially-loaded single-angles. Large deformation formulation as well as
elasto-plastic material response has been incorporated. The main purpose
of this research is to determine the axial load capacity of cold-formed
single-angle cross-sections as well as to study the behaviour of such
members.
Finally, the computational analysis aimed to verify ~he
correctness of the formulas introduced in some design codes conceming
the design of cold-formed single-angle cross-sections used in
transmission towers, and with affirmative results it would provide a
simple design formulas and a platform for further investigation by finite
element method rather than by time-consuming and costly experiments.
Formulas for the design of this type of transmission tower members and
its application are also introduced.