What is a Steel Frame Structural System?
Structural Steel Dome : Motor City,
Randburg, South Africa -
Courtesy of Prokon
Diameter = 161m Height = 34m
Nodes = 1260 Frame members = 3480
Well let's break down that question into several topics.
 |
What is a System? In the beginning of the term, the
class brainstormed an idea that would sum up the broad aspect of a system: |
"A System is a series of components
combined to attain a desired goal through a consistent and efficient
process."
|
What is a Structural System? The class was then asked
to elaborate on a specific system that relates to our engineering
discipline. |
"A Structural System is composed of
elements to transfer applied loads to the ground and to maintain spatial
integrity"
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Now let's focus on a specific type of structural system:
Steel Framing. |
Steel Framing is the use of Steel members, in a structural
frame, as the elements that transfer the applied loads to the ground.
There are many horizontal, vertical, and connection components
that are used with steel. Here is a list of the most common used
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Horizontal Components:
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- Beam
- A structural member, usually horizontal, whose main function is to carry
loads transverse to its longitudinal axis. These loads usually cause bending
of the beam member. Some types of beams are simple, continuous, and
cantilever.
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- C Shapes (b)
- A hot rolled shape called an American Standard Channel with symbol C.
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- "C" Section (b)
- A structural member cold-formed from sheet steel in the shape of a block
"C" which can be used by itself or back to back with another C
Section.
-
- Channel
- A hot rolled structural shape the looks like "[". There are
American Standard Channels designated by (C) and Miscellaneous Channels
designated by (MC).
- Joist
- A structural load-carrying member with an open web system which supports
floors and roofs utilizing hot-rolled or cold-formed steel and is designed
as a simple span member.
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Vertical Components:
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- Leveling Plate
- A steel plate used on top of a foundation on which a structural column can
be placed.
- Pipe
- A hollow cylinder of metal used for the conveyance of water or gas or used
as a structural column which comes in sizes of standard, extra strong and
double-extra strong.
- Rod (b)
- A smooth solid round bar used for the web system of a bar joist.
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Connection Components:
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- Angle
- A hot rolled shape called an Angle with symbol L which has equal legs or
unequal legs.
-
- Base Plate
- A steel plate welded to the base of a column which distributes the
column loads over an area of foundation large enough to prevent crushing
of the concrete and usually secured by anchor bolts.
-
- Bearing Plate
- The steel plate used for a joist or joist girder to bear on when they are
supported by masonry or concrete supports. This plate transfers the joist
reaction to the supporting structure and must be sized accordingly.
-
- Cap Plate
- A steel plate welded to the top of a column which a joist, joist girder,
or other structural member can bear on.
-
- Gusset Plate
- A steel plate used to connect structural steel members or to reinforce
members. It is usually inserted between the top or bottom chord of a joist
or joist girder.
-
(b) Can be used as a Vertical Component as well.
|
Typical costs and life
of elements of building construction
Average
Import Customs Value of Steel Per Net Ton |
Steel
is the primary material used in most commercial or large construction
projects. Most steel frames are designed
to achieve composite action with the concrete floor slab. The advantages
of 'composite construction' are now well understood in terms of structural
economy, good performance in service, and ease of construction. Coupled with this increase in the use of
steel frames has been a demand for higher quality in the building fabric
and services. It is recognized that the cost of the frame may only be 10
to 15% of the overall building cost, and therefore decisions on the choice
of the structural form are more influenced by the usability and
adaptability of the building to changing requirements.
An important factor, from the
point of view of the structural design, has been the demand from many
clients, letting agents and users, for longer column-free spans and
greater usable space. This can be readily achieved with steel frames, but
as spans increase, so does the depth of the floor structure necessary to
achieve economic design. As the ceiling to floor depth increases, so the
building heights and cladding costs increase. The challenge for structural
engineers is therefore to develop long span systems that achieve a ceiling
to floor depth consistent with traditional construction in steel or
concrete.* |
* Referenced from the Steel
Construction Institute website
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