This course introduces the types of cost estimation from the conceptual design phase through the more detailed design phase of a construction project. In addition, the course highlights the importance of controlling costs and how to monitor project cash flow. Students will work on a break-even analysis of construction tasks in a project.
History of Structural Steel
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Do curso por Columbia University
Construction Cost Estimating and Cost Control
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Quantity Take-Off and Measurement
James Sneath, Associate Director of Cost Management for Turner and Townsend, and Ian Taylor, Project Manager for Turner and Townsend, discuss Quantity Take Off and Measurement. Estimating cut and fill costs is taught along with a detailed example of using cut and fill software. Also covered in this module is the topic of deep foundations, concrete foundations and structural steel, measurement, masonry, glass curtain wall, facade and wall finishes.
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Ibrahim Odeh, Ph.D., MBAInstructor, Department of Civil Engineering and Engineering Mechanics, Columbia University
Director of Research and Founder, Global Leaders in Construction Management
Hi, and welcome to structural steel quantity takeoff.
Modern steel construction has become more prevalent since the late 19th century
as a result of the British leading the efforts of the Industrial Revolution.
As you can see on the screen, in the historic townscape of
Port Talbotf from the east of Wales of the United Kingdom,
Port Talbot is home of Port Talbot Steel Works,
which today currently employs roughly 10% of the town's population.
Having seen the success the English enjoyed from steel construction,
Australia, Germany, France and the United States were early adopters
of coal mining and steel production technology.
A great example of a success,
such as the Sydney Harbor Bridge, which was completed in 1932.
The bridge was created to span Sydney Harbor and enabled rail, pedestrian and
vehicle transportation, bringing economic growth and prosperity to the area.
Structural steel has a variety of different shapes, sizes and applications
that lend way to building immense structures in areas that were previously
impossible and has become a standard building material in modern construction.
To recap,
modern steel construction has been prevalent since the late 19th century.
It allows for structures in areas previously not possible, and
a variety of shapes, sizes, and applications exist.
So what is structural steel?
Simply steel is an alloy comprised primarily of iron and
carbon that is widely used in construction due to it's relatively low cost
to produce and high tensile strength.
In short, steel is merely iron that has had most of its impurities such as silica,
phosphorus and sulphur removed through the steel manufacturing process.
New steel is produced by combining limestone, iron ore, and
coal at very high temperatures into a unit known as a blast furnace.
Liquid iron, which is full of impurities, is then,
extracted into a basic iron vessel where a molten
iron is subjected to pure oxygen carbonation at very high speeds.
Once this process is complete, liquid steel is extracted
from the oxygen vessel and placed into molds to create billets.
These billets are then transported to high speed rollers
to create the various shapes and sizes structural steel can be used.
Thus steel has become one of the most versatile building materials known in
modern construction, as units can be created custom for individual projects.
It's very important to understand that steel can also be recycled and
repurposed by a very similar process.
And another method exists of steel making known as an electric arc furnace,
which we're not going to cover in this module.
So to recap, steel production, steel is an alloy comprised of iron and carbon.
New steel is produced by combining limestone, iron ore, and coal.
Liquid iron is extracted into a basic oxygen vessel.
Billets can therefore be rolled into multiple shapes and
sizes to meet the application's needs.
And if you'd like to learn about the steel manufacturing process,
please visit the link you can see at the bottom of your screen.
So as discussed in the previous slide,
steel can be formed into various shapes and sizes.
Here in the United States, steel standards are governed by the ASTM or
the American Society of Testing and Materials.
The two you will be primarily dealing with are here as follows.
The majority of structural steel falls under the ASTM Standard A36 or
the standard specification for carbon structural steel.
Hollow structural steel sections, which we will cover later in this module,
fall underneath the ASTM Standard A1085, or Hollow Structural Steel Members.
Similar to rebar, which was discussed in our concrete module,
the ASTM has created a table for its all standard structural steel sizes.
In this table, we are showing you a small sample of W27 beams.
Their height in inches and weight per linear foot.
Application of this table will come in later in the presentation.
Similar to structural steel sections, hollow structural steel sections
governed under ASTM 1085, will be represented in a similar table.
Here we are showing you a small sample of rectangular hollow structural steel,
or HSS members.
Their wall thickness is represented, sorry.
Their wall thickness is represented in inches.
And their weight is listed as per linear foot.
Once again, application of this table will come later on in the presentation.
Okay, and now for understanding structural steel takeoff.
Takeoff.
The unit of measurement for structural steel is pounds per linear foot.
The calculation is quantified by capturing the linear footage of the structural
member times the weight of the member itself.
Conversion will be converting form pounds to tons.
The calculation is performed at 2,000 pounds is equal to one U.S. ton.
And a good tip for
structural steel takeoff is grouping all the steel together by types and
sizes and specifying the steel by their floors and locations where possible.
In modern construction,
steel will typically be formed into the following sections.
A wide flange beam or w-section.
You will typically see this specified on construction documents as such.
For example purposes, we have produced a W12 by 79 member.
This translates into a member that is 12 inches in depth and
weighs 79 pounds per linear foot
The American Standard Channel or C-Section.
This is a steel channel section that is specified as such.
For illustration purposes, we have decided to show you a member that is C10 by 25.
And this translates simply into a member that is ten inches deep and
weighs 25 pounds per linear foot.
Angles or L-sections.
This is known as a steel angle section.
The specification will be found on construction documents as such.
For illustration purposes, we have shown you an L angle that is eight by eight for
each one of it's legs and is five eighths of one inch thick.
For this particular type of member,
you must refer to ASTM standard A36 tables in order to determine the weight.
WT-sections.
These sections are created from wide flange beams.
The specification will be found on construction documents as such.
For illustration purposes we have decided to show you a 22 by 132 WT section.
And this translates into a section that is 22 inches tall and
weighs 132 pounds per linear foot.
Structural tubing or hollow structural steel sections.
This is a square structural steel section,
the specifications on construction documents will be found as such.
And by example we are showing you a member that is 18 inches long by 18 inches wide.
And is seven eighths of one inch thick.
Again you must refer to the ASTM tables, remembering that hollow structural steel
members refer to table 1085 in order to determine their weights per linear foot.
Similar to the rectangular or square sections,
you have round structural steel sections.
Various specifications will be found as such and this translates
to a 20 inch outside diameter of the round member with a thickness of one-half inch.
Again, you must remember to refer to the ASTM tables 1085 in
order to determine the weight.
Another common member that you will experience
in modern construction are that of steel joists.
Structural steel joist members are specified as 16K5 for
illustration purposes.
This translates to a member that is 16 inches in depth and
K5 is the actual specified member.
You must refer to the manufacturer's specifications in order to determine
the weights.
On this side you will see that manufacturers will publish
the information regarding their standard products of their websites.
The example shown here is from Bullcraft,
a large national manufacturer steel joist and decking products.
Remember you can always reach out to a local representative from one of these
manufacturers or utilize your professional network
should the information not be readily available on the web.
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