Steel Structure Design and Costs

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Questions and Answers

What accounts for a larger portion of the cost in a typical steel structure compared to materials?

Transportation costs

Material procurement

Labor costs (correct)

Administrative overhead

What is essential before the structural analysis of building frames can be conducted?

Selection of the construction site

Completion of initial drafts

Decision on the primary building material (correct)

Approval from regulatory bodies

What type of designs should ideally be prepared when evaluating framing plans?

Single comprehensive design

Only the most cost-effective design

Various alternative designs (correct)

Similar designs with minor alterations

Which of the following is NOT mentioned as a primary building material to be used?

Timber Signup and view all the answers

Which specification is primarily concerned with the design of structural steel buildings?

American Institute of Steel Construction (AISC) Signup and view all the answers

What is the primary focus of the material discussed in the content?

Design of individual structural steel members Signup and view all the answers

Which organization covers the design of highway bridges and related structures?

American Association of State Highway and Transportation Officials (AASHTO) Signup and view all the answers

What must be analyzed to inform the selection of appropriate cross sections for structural members?

Forces and bending moments Signup and view all the answers

What did the Bessemer converter enable in the 19th century?

The displacement of wrought iron and cast iron by steel Signup and view all the answers

What are considered the 'building blocks' of the structure in structural design?

The individual structural components Signup and view all the answers

What should be done for each framing plan investigated?

Evaluate and compare costs Signup and view all the answers

The first structural steel railroad bridge was the Eads bridge, built in which year?

1874 Signup and view all the answers

Which material is primarily used in the production of steel?

Iron Signup and view all the answers

What type of steel does the American Iron and Steel Institute (AISI) specification focus on?

Cold-formed steel Signup and view all the answers

In which city was the first building with a steel frame completed?

Chicago Signup and view all the answers

Which organization was formerly known as the American Railway Engineering Association?

American Railway Engineering and Maintenance-of-Way Association (AREMA) Signup and view all the answers

What is the principal component of structural steel?

Iron Signup and view all the answers

Which of the following statement is true about plain carbon steels?

They primarily consist of iron and carbon. Signup and view all the answers

What effect does carbon have on structural steel?

Both increases strength and reduces ductility. Signup and view all the answers

In the context of structural steel, the term 'yield stress' refers to which of the following?

Either yield point or yield strength. Signup and view all the answers

Which grade of structural steel has a minimum yield point of 50 ksi?

A992 Signup and view all the answers

What is the maximum yield to tensile ratio for A992 steel?

0.85 Signup and view all the answers

Which type of steel has properties enhanced by a higher percentage of alloying components?

High-alloy steels Signup and view all the answers

What is one common characteristic of low-alloy steels?

They feature reduced ductility for increased strength. Signup and view all the answers

What distinguishes the flanges of the W-shape from those of the S-shape?

The flanges of the W-shape are wider in relation to the web. Signup and view all the answers

What does the prefix 'WT' indicate in the designation of a Structural Tee?

It denotes a specific parent shape. Signup and view all the answers

How is the designation of an S-shape formed?

With a letter indicating the shape type and two numbers for depth and weight. Signup and view all the answers

Which of the following describes the M-shape?

It has two parallel flanges and a web. Signup and view all the answers

What is a characteristic of the American Standard Channel (C-shape)?

Its depth is exact rather than nominal. Signup and view all the answers

What is an HP shape primarily used for?

Bearing piles. Signup and view all the answers

In the designation 'L6 3 6 3 3/4', what do the first two numbers represent?

The lengths of the two legs of the angle shape. Signup and view all the answers

How is a Structural Tee commonly produced?

By cutting from a W-shaped member at mid-depth. Signup and view all the answers

Which statement is true regarding the W-shapes?

W-shapes can vary in flange thickness even if they share the same nominal size. Signup and view all the answers

What does the designation 'HP14 3 117' indicate about the HP shape?

It is 14 inches deep and weighs 117 pounds per foot. Signup and view all the answers

What is a feature of the inside faces of the flanges of an S-shape?

They slope with respect to the outside faces. Signup and view all the answers

What is the correct representation of the flange thickness for the angle shapes?

It is the same for both legs in equal-leg angles. Signup and view all the answers

What differentiates the profile of the W-shape from the S-shape's flanges?

The W-shape flanges are parallel to each other. Signup and view all the answers

Study Notes

Steel Structure Cost Breakdown

Labor and other costs represent a larger portion of the overall cost of a steel structure compared to materials.

Design Considerations

Multiple framing plans should be evaluated and compared for cost effectiveness.
Structural analysis is required for each plan to determine forces and bending moments in individual members.
Selection of the appropriate cross section depends on the calculated forces.
The primary building material should be chosen first (e.g., reinforced concrete, structural steel, or a combination).

Importance of Structural Steel Design

Understanding component design ("building blocks") is crucial for overall structural system efficiency and economy.

Key Organizations in Steel Design

American Institute of Steel Construction (AISC): Provides design specifications for steel buildings and connections.
American Association of State Highway and Transportation Officials (AASHTO): Covers design of highway bridges and related structures.
American Railway Engineering and Maintenance-of-Way Association (AREMA): Covers design of railway bridges and related structures.
American Iron and Steel Institute (AISI): Deals with cold-formed steel.

Early Uses of Iron and Steel

Iron was used in tools as early as 4000 BC.
Cast iron and wrought iron were used in bridge construction in the 18th and 19th centuries.
Steel replaced wrought iron and cast iron in construction with the introduction of the Bessemer converter in 1855.

Properties of Structural Steel

Yield stress (Fu & Fy): The primary properties needed for structural steel design.
Chemical composition: Determines strength and ductility.
Carbon: A component of steel that contributes to strength but reduces ductility.

Categories of Structural Steels

Plain carbon steels: Primarily iron and carbon (less than 1% carbon).
Low-alloy steels: Include additional components (less than 5%) for increased strength at the cost of reduced ductility.
High-alloy or specialty steels: High carbon content, additional components, and enhanced qualities (e.g., corrosion resistance).

Steel Grade Identification

American Society for Testing and Materials (ASTM): Designates different grades of structural steel.

Examples of Steel Shapes

Wide-flange (W): Two parallel flanges, single web, two axes of symmetry; shapes with the same nominal depth are grouped into families.
American Standard Shape (S): Similar to the W-shape but with narrower flanges relative to the web and sloping inside flanges.
Angle (L): Available in equal-leg or unequal-leg versions.
Channel (C): Two flanges and a web with one axis of symmetry, sloping inside flanges.
Miscellaneous Channel (MC): Similar to the C-shape.
Structural Tee (WT, ST, MT): Produced by splitting an I-shaped member at mid-depth.
M-shape: Two parallel flanges and a web, but not a W or S shape.
HP: Used for bearing piles, parallel flange surfaces, approximately equal width and depth, equal flange and web thicknesses.
Bars: Circular, square, or rectangular cross sections.

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Description

Explore the intricacies of steel structure design, including cost breakdowns for labor and materials. This quiz covers essential design considerations, structural analyses, and the significance of selecting appropriate building materials and components. Learn about key organizations that influence steel design and their specifications.