what is steel?

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American Institute of Steel Construction

Title Slide

a teaching primer for colleges of architecture

The Material Steel

STEEL

STRUCTURE OF THE EVERYDAY :

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Project Director

Slide Design & Graphics

Production Assistants

IT Coordination

Photography

Software

For additional information, please contact:

College of Architecture, UNC-Charlotte

PRODUCTION TEAM College of Architecture UNC - Charlotte

CREDITSThe Material Steel |

David Thaddeus, AIA, Associate Professor [email protected]

David Thaddeus, AIA

Jennifer AugustBrittany EakerKathy Phillips

Matt Parker

David Thaddeus, AIANate Robb

PowerPointPhotoshop

Deborah J. Arbes, RA

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This project was made possible through funding from the American Institute of Steel Construction (AISC) with support from the College of Architecture at the University of North Carolina at Charlotte

Special thanks to the following people at AISC for their support and help over the duration of the project:Fromy Rosenberg, PE, Director, AISC University ProgramsMegan Maurer, Coordinator, AISC University Programs

The following people have my sincere gratitude for serving on the Focus Group and offering their comments and feedback in the development of this project :

Kurt Baumgartner, AIA, JIA, University of Illinois at Urbana Champaign Terri Meyer Boake, Associate Professor, University of WaterlooThomas Fowler, Associate Professor, California Polytechnic State UniversityHarry Kaufman, PE, NCARB, Professor, Southern Polytechnic State UniversityKemp Mooney, Kemp Mooney ArchitectsTim Mrozowski, AIA, Professor, Michigan State UniversityRyan Smith, Assistant Professor, University of Utah

The following AISC members have provided invaluable insight into the content of this teaching aid:

Ron Bruce, PE, President, Builders Steel Company, North Kansas City, MOLawrence Kruth, PE, Engineering & Safety Manager, Douglas Steel, Lansing, MIDavid McKenzie, PE, Vice President - Engineering, SP International, North Kansas City, MO

Acknowledgements

ACKNOWLEDGEMENTSThe Material Steel |

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The American Institute of Steel Construction (AISC) is a non-profit technical institute and trade association established in 1921 to serve the structural steel

design community and construction industry in the United States.

AISC is offering this teaching aid and learning tool for educational purposes only. The data and information in this presentation is not intended for use in the

physical construction of steel structures.

The information presented here is considered public information and as such may be distributed or copied. The use of appropriate credit to for images, byline,

animations, and content is requested.

We hope that you and your students will find this information useful.

Please contact Fromy Rosenberg ([email protected]) for further information on AISC or for feedback on this teaching / learning product.

Please contact David Thaddeus ([email protected]) for questions or comments on the content of this project.

Terms

TERMSThe Material Steel |

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The Material Facts Chemical Composition Production Structural Properties Terminology Profiles in Steel Protection of Steel Members Appropriate Technology / Sustainability of Steel

Module I Contents: Overview

CONTENTS

CONTENTSThe Material Steel |

Clinical Sciences Research, Stanford University . Palo Alto, CaliforniaSir Norman Foster

The de Menil Collection Museum Houston, TexasRenzo Piano

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Steel | The Material Facts

Today steel is produced in over 50 countries all across the world.

In 2003, China was the first country to produce more than 200 million tons of crude steel in a year (more than 20% of the world’s steel is produced in China).

China is the world’s largest consumer of steel (cars, general industry, construction…)

Japan is the largest exporter of steel.

More than 60% of the steel produced annually is from recycled steel. Properties of steel are not altered by how many times it is recycled. Per pound of material, steel is the most efficient of all building materials. A small amount of steel can do load-carrying tasks with a fraction of the material needed from other materials such as concrete or wood. Steel is the densest of structural materials and therefore handles longer spans, and produces lighter structures with the greatest economy. Steel can be found in fasteners (nails…), structural components, rebar, sheet-metal, appliances, cars, ships, …

To every ton of Portland Cement produced, 3 tons of wood and 10 tons of steel are produced.

The United States and China are the largest importers of steel.

British Inventor Henry Bessemer produced the first economical steel in 1856.

Steel is the world’s most recycled material. Steel is recycled mostly from junk cars (3-400,000 cars per year per steel mill; 27 cars / minute in North America ).

THE MATERIAL FACTS

Steel was first produced in 1738 in Sheffield, England, know as “crucible steel” in was very pure, but difficult and expensive to produce.

The Material Steel |

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Soft & Malleable Hard & Brittle

Wrought Iron Cast Iron

< 0.2 % Carbon < 3 - 4 % Carbon

Steel0.2 - 2 % Carbon

Carbon Steel

Mild Steel0.2 - 0.25 % Carbon

Medium Steel0.25 - 0.45 % Carbon

Hard Steel0.45 - 0.85 % Carbon

Spring Steel0.85 - 1.85 % Carbon

Alloy SteelStainless Steel

Weathering Steel

Combinations of:Chromium, Cobalt, Copper,Molybdenum, Nickel,Tungsten, Vanadium

+

+Controlled amounts of:

Manganese, PhosphorousSilicon, Sulfur, Oxygen

Steel | Chemical Composition

CHEMICAL COMPOSITIONThe Material Steel |

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Steel is an alloy of Iron, Carbon (<2%), and Manganese (<1%). It also contains small amounts of Phosphorous, Silicon, Sulfur and Oxygen

Carbon content greatly affects the properties of steelMore Carbon increases : strength, hardness, corrosion-resistanceMore Carbon decreases : malleability, ductility, and weldabilityThe amount of Carbon does NOT affect the Modulus of Elasticity (E)

of the Steel

Stainless Steel Adding 15-18% Chromium and 7-8% Nickel produces corrosion-resistant steelCor-Ten Steel Sculpture

By Richard Serra

Museum of Modern Art

Fort Worth, TX

Weathering Steel (Cor-Ten Steel) Adding Copper and Phosphorous creates a steel that forms an oxide coating, rust, that adheres to the base metal and prevents further corrosion

Steel | Chemical Composition

these chemical elements are controlled to provide consistent quality and grade of steel

Carbon Steel

is Carbon Steel to which one or more chemical elements have been added to achieve certain physical or chemical properties

Alloy Steel

CHEMICAL COMPOSITIONModule 1 |

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Steel | Production

Open Hearth Furnace (OHF) Basic Oxygen Furnace (BOF) Electric Arc Furnace (EAF)

Refining is the addition of alloys to obtain certain characteristics in the steel:

U.S. has roughly 25% of world coal supply.

Steel is heated to molten state to remove oxides

Three Types of Production Furnaces:

Iron ore constitutes 5% of earth’s crust, 70% of earth’s core is iron.

Molybdenum- strength. Manganese- resistance to abrasion and impact. Vanadium- strength and toughness. Nickel and chromium- toughness, stiffness and corrosion resistance.

Electric Arc Furnace (EAF) process is environmentally safer.

Casting: Liquid steel is cast into semi-finished products; billet, blooms

By 1980s computer controls were prevalent in steel mills.

Whether BOF or EAF all steel is recycled back into steel, so although BOF has a lower % of recycled steel, it is still as environmentally friendly.

PRODUCTIONThe Material Steel |

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Open Hearth Furnace (OHF): Discontinued in USA due to OSHA and EPA regulations, it wasted energy and manpower.

Last Open Hearth Furnace in U.S. was closed down in 1980s.

Extreme heat burned out impurities in iron.

Accepts variable amounts of scraps (20-80%) .

3000°F minimum temperature required, 10 hours to accomplish.

Worldwide, 3.6% of steel produced in 2003 was OHF.

PRODUCTIONThe Material Steel |

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Steel | Structural Properties Ductile, absorbs energy

Quick erection.

Flexibility, Strength, Durability, Functionality.

Steel is a lightweight solution that is strong enough to allow for longer spans.

Steel buildings are light and therefore require smaller foundations than heavier building materials.

Less time on construction site reduces cost.

Shop Fabrication reduces on-site work down to the assembly and the erection of frame only.

Shop Fabrication reduces on-site weather delays.

The Material Steel | STRUCTURAL PROPERTIES

Charles de Gaulle Airport Paris . France

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Structural Properties: Overview

Steel is consistent, isotropic and homogenous.

Density 490 LBS./ FT 3 or 0.25 LB. / IN 3

(concrete: 144 LBS./ FT 3 or 0.08 LB./ IN 3, wood: 35 - 40 LBS. / FT 3 )

Steel is capable of precise tolerances and with proper detailing will provide an exceptionally tight building envelope.

Minimum on-site waste.

Strong and stiff for very little weight.

The Material Steel | STRUCTURAL PROPERTIES

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TERMINOLOGY

Steel | Terminology


Cold Formed

Hot Rolled

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TERMINOLOGY

Steel | Terminology


Web : Shear

Flange : Bending

Coping

Reduced Beam Section – RBS (Dogbone)

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TERMINOLOGY

Steel | Terminology


Fabricator

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TERMINOLOGY

Steel | Terminology


Shear Studs

Detailer

Camber

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TERMINOLOGY

Steel | Terminology


Groove Weld Puddle WeldFillet Weld

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TERMINOLOGY

Steel | Terminology


Horizontal BridgingCross Bridging

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TERMINOLOGYThe Material Steel |

Erector

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Architecturally Exposed Structural Steel lends itself naturally to sustainable building. AESS avoids additional finishes and, therefore, saves the energy which would have been used to produce and transport those finishes. Using steel whenever possible increases the amount of recyclable content in building. Using Bolted connections vs. Welded makes disassembly / re-use easier. The integration of structural and mechanical components which is facilitated by AESS can save building materials. Besides being structural, Hollow Steel Sections (HSS) can also convey hot water and therefore contribute to the heating or plumbing of the building. The finish color used on the AESS system can enhance reflectance, reducing lighting and thus saving A/C. Use of steel and glass atria for natural light (a design feature common in AESS buildings) can also reduce the demand for artificial lighting and in turn A/C demand. The high visibility of an AESS system demands a very high level of attention to the detailing of the steel members, their finishes and their connections.

TERMINOLOGYThe Material Steel |

Architecturally Exposed Structural Steel (AESS)

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Remarks Applications Name Features / Strengths

Sample Designation Size Range

W 12 x 50 BendingCompression

BeamsColumns

3/8”< tf < 2” 1/4”< tw < 5”

Wide Flange 12 : Nominal depth50 : Weight / Lin. Ft.

W 4 – W 449 #/ft – 30 #/ft

M-Shapes M 14 x 18 14 : Nominal depth18 : Weight / Lin. Ft.

M 5-M 144.4-18 #/ft

Bending BeamsColumns

Smaller members that are not W, HP, S

HP 14 x 102 CompressionBearing

Piles tw = tf < 1” 14 : Nominal depth102 : Weight / Lin.Ft.

HP 8 – HP 1436 - 117 #/ft

Bearing Piles

S 15 x 50Bending

BeamsColumns

Flanges slope at 2:12Not as stable as W-shapes

15 : Nominal Depth 50 : Weight / Lin. Ft.

S 3 - S 24 5.7 - 121 #/ft

American Standard (I-beam)

PROFILES IN STEELThe Material Steel |

Steel | Profiles in Steel

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C 10 x 30

Bracing Lintels Stairs Trusses

Nominal Depth = Actual Depth No torsional strength

10: Actual depth30: Weight / Lin. Ft.

C3 - C154.1 - 50 #/ft

American Standard Channel

Tension Compression Bending

MiscellaneousChannels

MC 13 x 50 13: Actual depth50: Weight / Lin. Ft.

MC 6-186.5 - 58 #/ft


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WT 5 x 9.5MT 5 x 4.5ST 5 x 12.7

CompressionTensionBending

BracingTrussesLintels

Split W -shape lengthwise

Structural Tees: 5: Nominal depth9.5, 4.5, 12.7:Weight/Linear Ft.

WT2 - WT18; 4.5 - 179.5 #/ft

MT2.5 – MT7; 2.2 - 9.45 #/ft

ST1.5 – ST12; 2.85 - 60.5 #/ft

Equal Leg Angle

L 4 x 4 x 1/2 4 : Leg size½”: Leg thickness

L 1 x 1 x 1/8-L 8 x 8 x 1 1/8

CompressionTension Bending

BracingTrussesLintelsConnections

t = 1/8” –

t = 1- 1/8”Unequal Leg Angle

L 6 x 4 x 1/2 6: Long leg 4: Short leg½”: Leg thickness

L 2 1/2 x 2 x 3/16 - L 9 x 4 x 5/8


Cut from WCut from MCut from S

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Pipes



StableGood in Torsion

ColumnsTrussesBraces

CompressionTension

20” side12” side5/8” thickness

4 x 4 x 1/2 4” each side½” thickness

2 x 2 x 3/16 – 8 x 8 x 5/8

t: 3/16” - 5/8”

ColumnsTrusses Braces

Rectangular 20 x 12 x 5/8

Square

StableGood in Torsion

ColumnsTrussesBraces

CompressionTension

½” -12” diameter½” -12” diameter 2 ”- 8” diameter

Standard Extra Strong Double Extra Strong

CompressionTension


3 x 2 x 3/16 – 20 x 12 x 5/84

t: 3/16” - 5/8”

6” Φ Extra . Strong

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Objective:

To maintain structural integrity for a specified period of time to allow the evacuation of occupants and secure access for firefighters.

Steel | Fire Protection

Fire resistance is expressed in units of time it takes the structural member to reach failure by heating.

Steel loses its integrity at 500°C (~930°F), and most of its strength at 600°C (1100°F).

Lighter steel sections will require more fire protection than thicker sections since heavier sections will heat up at a slower rate.

Steel sections that are in contact with concrete take longer to heat up than ones without contact.

The thickness of fire protection material dictates its fire rating and the protection time it delivers.

Light gauge steel products heat up very quickly.

FIRE PROTECTIONThe Material Steel |

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Minimum fire-resistance ratings for primary and secondary structural members is provided in Building Codes and is based on Occupancy and Type of Construction.

The total area and weight of a building determines its Building Type.

Most multi-story steel frames are Type I or Type II - non combustible.

Primary structural members include: columns, beams, girders, trusses and other structural members directly connected to columns.

Steel that is to be fire protected should not be painted or galvanized in order to adhere straight to the base metal.

Fire protection systems are determined by appearance, durability, cost, ease of installation, finish quality, surface preparation needed, and speed of application.

Most fire protection systems can provide up to 4 hours (non-combustible) including intumescent paints.


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Cost (Relative)

Care must be taken to achieve even application

Surface Preparation

Material Quality Appearance Information Installation Fire Rating

Applied to unpainted steel

$$ to$$$

May be used exposed Overspray Can be troweled

Not typically aesthetically acceptable in public areas

Easy to cover complex areas/details Must mask adjacent areas Very Messy Interferes with other trades

$

increasingthicknessaddsdurabilitybut alsoweight


Sprayed Fire Resistant Materials (SFRM) | Two Types: Reactive and Non-Reactive

Thin-filmIntumescentPaint

Epoxy BaseIntumescentIndustrialApplication

&

Provides insulation by expanding and providing “char” of low heat conductivity Kicks in at 200°-250°, way before steel starts to fail Thickness: 0.03” – 0.4” Epoxy Base Up to 1” thick

&

Mineral Fiber(Dry)

Cementitious(Wet)

SPRAYED

Non-reactive

Reactive Thin coat allows steel profile to retain detail and remain aesthetically pleasing attractive decorative finishes are available

Epoxy Base has course texture

Brush or spray applied.

Easy to cover detail (around pipes, etc.) Easy to repair Wet trade Must have proper atmosphere conditions at time of application Overspray must be considered

Limited fire- protection duration

Steel preparation may be necessary

Up to 1 Hr.(standard)

Can achieve 4 Hrs., but is costly Thicker = more passes = more cost

Up to 4 hrs. 1 hr. per inch

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Cost (Relative)

Surface Preparation

Material Quality Appearance Information Installation Fire Rating


Blanket Insulation

ConcreteEncasing

Unsightly (needs to be hidden)

Dry. No effect on other trades

$

Less popular today with the introduction of lighter fire protection materials

Same as concrete or concrete block construction

lost space due to massiveness

$$$ Unsurpassed Durability

Non-reactive Uniform thickness

Applied to unfinished steel

varies with thickness


Typical construction methods

adds significant weight to the structure

Weatherability

1-2 Hrs.

Non-reactive Acceptable

Clean, boxed appearance can be left unfinished in unseen areas or finished where visible

Dry (no wet mess)

Difficult in small / detailed areas.

Slower than some other methods

Uniform thickness assures the quality of the rating Typical for columns less usual for beams


$$

½” = 1 hr.

Up to 4 Hrs.

GypsumBoard

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Additional Fireproofing Methods

Water and antifreeze for Hollow Steel Section (HSS)

Metal flame shields.

Filling HSS with concrete increases their compressive ability while also providing fire protection.

- Plain concrete fill (1-2 hours), steel yields after 20-30 minutes, then concrete takes over, concrete can only last so long, then cracks and collapses. - Adding steel fiber to concrete (2-3 hours) helps carry compression loads longer. - Adding rebar (2-3 hours).


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Plain steel corrodes quickly in moist environments.

Corrosion of steel does not occur if relative humidity <60%; at 70% relative humidity corrosion is accelerated.

Corrosion (oxidation) is an electrochemical reaction that oxidizes the iron in steel, commonly called rust.

This makes the steel look unsightly.

It eventually makes steel thinner, vulnerable to water infiltration, it spalls, loses its structural strength, gradually disintegrates, and ultimately fails.

When a metal oxidizes, it reverts to its natural, lower energy state.

Zinc is a less noble metal than steel, but corrodes at a slower rate.

CORROSION PROTECTION

Steel | Corrosion Protection

Objective:

To protect structural integrity from the environmental forces, which act over time, to deteriorate the individual members of the system.


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Internal Alloying

Involves altering the composition of the steel alloy to include nickel, chromium and other corrosion resistant elements.

This results in stainless steel or weathering steel (weathering steel forms a tight oxide layer that adheres to the base metal and protects it).

This method of protection (internal alloying) is more expensive than painting or metallic coating.

CORROSION PROTECTIONThe Material Steel |

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Barrier Protection

Paint

Is a barrier protection system.

Not impervious to moisture infiltration.

Scratches and thus loses its protection ability.

Weather conditions affect application.

Metal Coating: Zinc, Aluminum (anodizing)

Cheap, easy to apply by dipping (easy to coat details), maintenance free.

Barrier protection system that is impermeable.

Metallic zinc coating has good adhesion to base metal, abrasion and corrosion resistance.

Zinc is a reactive material which will eventually corrode and erode away.


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Galvanized protection is proportional to its thickness and corrosion rate.

Steel is protected by the sacrificial corrosion of the zinc layer ( 1/10 the rate of steel corrosion).

If scratched, adjacent steel will not corrode.

Twice the coating thickness will result in twice the protection.

Amount of protection also depends on the environment in which the steel will be used (industrial atmospheres, marine, soil, near chemicals…).

Galvanizing is done in a factory where quality is consistent and work is independent of the weather.


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Surface Preparation and Hot-Dipping:

Surface preparation is essential for any barrier protection to be effective.

Steel surface may be prepared by:

Caustic cleaning - removes organic contaminants such as dirt, oil, etc by dipping in a hot alkali solution.

Pickling - removes scale and rust by dipping in an acid solution.

Fluxing - removes oxides and prevents further oxidation.

If surface is not clean, zinc will not metallurgically react with the steel.

Unclean areas will come out uncoated from hot-dip process.


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Hot dipping involves complete immersion of member in 98% molten (840°F) zinc.

The molten zinc reacts with steel to form a series of alloy layers.

Members are entirely coated on all surfaces including all details.

Hot-dip galvanizing metallurgically binds the zinc coating to the base metal and provides protection from corrosive environments.

Hot-dip galvanizing of hollow steel sections (tubes and pipes) will coat both inside and outside allowing indoor / outdoor use.


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Steel is the most recycled product in the world.

Changes in the processes of steel production have reduced energy demands. The use of continuous casting eliminates energy demands for re-heat treatment of steel.

Steel buildings and other products are consistently salvaged and recycled. Concrete is crushed and used as road fill; rebar is recycled.

Although steel is locally manufactured, not all raw ingredients for B.O.F. are locally extracted.

Four R’s of sustainability: Reduce, Re-use, Recycle, and Restore.

Steel producers are constantly striving to reduce emissions into air and water, and in general to soften

the impact on the world environment.

SUSTAINABILITY

Steel | Sustainability


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Recycling steel is done for economic reasons in addition to the environmental benefits.

Most steel products (cars, appliances, bridges, buildings…) have longevity of use and so there is a shortage of steel to recycle.

Since the supply of steel for recycling is less than demand, raw materials for B.O.F. continue to be mined.

SUSTAINABILITYThe Material Steel |

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Once a steel appliance is melted down, it may find new life as a steel column, a can of soup, a car, or an appliance again.

Environmental efficiency of materials is analyzed according to the LEED performance standard or embodied energy (life cycle inventory) approach (cradle to grave and cradle to cradle).

Efficiency of material recycling can be measured either by recycled content or reclamation rate (number of times it is recycled).

Magnetic properties of steel permit easy separation from other building materials after demolition.


The De Menil Collection Museum . Houston, TexasRenzo Piano

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The North American steel industry has been recycling steel scrap for 150 years through 1800 scrap processors and 12000 auto-dismantling facilities.

Whether B.O.F. or E.A.F. product, steel is recycled into other steel.

Steel products have an endless life through infinite recovery cycles without losing workability or strength and so may be a perfect application of “cradle to cradle” concept.

Re-using steel could be through disassembly for later re-assembly, or through re-use on another project or through re-melting in a furnace.


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Steel that is to be re-used may be tested for yield strength or carbon content.

Chemical tests are also used to verify the weld-ability of recycled steel.

Through the use of smaller and lighter members for longer spans than other materials, steel will reduce the buildingsection and thus the sizes of mechanicalsystems needed.



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In some instances, using a steel frame instead of a concrete frame will result in half the dead load and half the foundation weight.

Steel is a green building product.

In general, it is often more economical to salvage a building rather than sending it to the landfill.

Steel industry accounts for 6% (approximately 45 Billion M Watts) of total electrical energy consumption in U.S.


Since 1999, construction of all new federal facilities must apply sustainable design principles.

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Recycling Facts and Figures

70 Million tons of steel recycled annually.

60% of which was derived from construction.

400 Million tons worldwide.

1.5 x all other recycled material.

1 ton recycled steel saves: 2500 lbs iron ore 1400 lbs coal 120 lbs limestone

LEED: Commercial construction produces 2-2.5 lbs solid waste / sq.ft. in demolition. This may be recycled or re-used.


Nasher Sculpture Center . Dallas, TexasPeter Walker, Landscape Architect

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Improved Production Methods

Early Recycling Processes: 100 tons of raw material yielded 60 tons steel. Current Recycling Processes: 100 tons of raw material yielded 90 tons steel.

B.O.F. 25-35% scraps. E.A.F. 90 -100% scraps.

In 2003: 60.2% steel cans, 102.8% cars, 89.7% appliances, 96% structural steel members, 60% rebar were recycled.

Total 70.7% of all steel products are recycled.

In U.S. most structural shapes and rebars are produced in E.A.F. HSS are produced in B.O.F.


Cy Twombly Gallery Houston, Texas

Renzo Piano

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USGBC - US Green Building Council

LEED - Leadership in Energy and Environmental Design

LEED is a performance, not a descriptive standard. Most widely used green building rating in U.S. 69 possible points Platinum 52+ Gold 39-51 Silver 33-38 Certified 26-32

(not much cost in securing ‘Certified’ level)


Nasher Sculpture Center Dallas, TexasRenzo Piano

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LEED Core Categories


Clinical Sciences Research, Stanford University . Palo Alto, California Sir Norman Foster

• Sustainable Sites 14 credits possible Local ecology, near public transport, reduction of commuting by car.

• Water Efficiency 5 credits possible

Buildings account for 1/6 fresh water consumption water efficient fixtures reduce this amount.

• Energy and Atmosphere 17 credits possible

Renewable and green power sources.

• Materials and Resources 13 credits possible

Conserve raw materials and resources (fossil fuels) Steel contributes most to this category.

• Indoor Environmental Quality 15 credits possible

Air quality, thermal comfort, daylight.

• Innovation and Design Process 5 credits possible

Integration of systems.

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LEED Core Categories



Sustainable Sites - 14 credits possible Local ecology, near public transport, reduction of

commuting by car.

Water Efficiency - 5 credits possible Buildings account for 1/6 fresh water consumption water efficient fixtures reduce this amount.

Energy and Atmosphere - 17 credits possible

Renewable and green power sources.

Materials and Resources - 13 credits possible

Conserve raw materials and resources (fossil fuels) Steel contributes most to this category.

Indoor Environmental Quality - 15 credits possible

Air quality, thermal comfort, daylight.

Innovation and Design Process - 5 credits possible

Integration of systems.

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Materials and Resources

2: Building Re-use Conservation of existing resource, no environmental impacts from transportation, steel buildings more likely than others for re-use, easy and cheap retro fits for adaptive re-use.

Encourages use of existing materials over new materials saves cost of added manufacturing energy

High recycled content.

Materials to be manufactured within 500 miles of fabricator.

Raw materials extracted within 500 miles of site (fabricator).


The Clark Center, Stanford UniversityPalo Alto, California

Sir Norman Foster

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the end

The Material Steel | The American Institute of Steel Construction