Design of Steel Structural

803459-3

Mohammed Alsabban

• masabban@uqu.edu.sa• Office : 1153• Ext. 1142• Mobile 0-5555-10-233• Office Hours:

– Sun 8am:10am– Tue 11am:12 noon– Wed 5pm:6pm

Text

• Book: Structural Steel Design• Authors:

– Jack C. McCormac and – Stephen F. Csernak

• Publisher: Pearson• Edition: Fifth (International)• Year: 2012

Manual

• 14th edition of the Steel Construction Manual (AISCM)

• Based on the 2010 Specification for Structural Steel Buildings (ANSI / AISC 360-10), (AISCS)

Topics Covered During ClassS/N Topic title Lecture

HoursWeeks

(Equivalent)

1 Introduction to Structural Steel Design 2 0.672 Specifications, Loads, and Methods of Design 1 0.333 Analysis of Tension Members 3 14 Design of Tension Members 3 15 Intro to Axially Loaded Compression Members 3 1 First Term Exam 1 0.336 Design of Axially Loaded Compression Members 2 0.677 Design of Axially Loaded Compression Members (Continued) and Column

Base Plates3 1

8 Introduction to Beams 2 0.67 Second Term Exam 1 0.339 Design of Beams for Moments 3 1

10 Design of Beams-Miscellaneous Topics (Shear, Deflection, etc) 3 111 Bending and Axial Force 3 1 Third Term Exam 1 0.33

12 Bolted Connections 2 0.66 Forth Term Exam 1 0.33

13 Eccentrically Loaded Bolted Connections and Historical Notes on Rivets2 0.67

14 Welded Connections 3 1 Fifth Term Exam 1 0.33 Review 3 1 Final Examination 2 0.67 Total 45 15

Advantages• Great Strength• Light weight• Ease of fabrication• Uniformity• Elasticity• Permanence• Ductility• Toughness• Additions to existing structures• Ability to be fastened together by several simple connectors• Adaptation to prefabrication• Speed of erection• Ability to be rolled into wide variety of sizes and shapes• Reuse• Scrap value

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Structural Steel

Disadvantages

• Corrosion• Fireproofing Cost• Susceptibility to buckling• Fatigue• Brittle fracture

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Structural Steel

Effect of temperature on yield strength

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First Completely Framed with Structural Steel Building

Completed in Chicago in 1890

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Historical Note

Rolled-steel shapes

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Cold-formed shapes

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Concrete floor slabs• Cast on formed steel decks

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Metric Units

• The metric equivalents of the standard U.S. shapes are provided in section 17 of AISCM

• W920 X 449 means 920 mm deep and weight 449 kg/m

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Stress-Strain Relationships• Typical stress-strain diagram for mild or low-

carbon structural steel at room temperature

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Stress-Strain Relationships• Typical stress-strain curves

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Brittle steel

• Typical stress-strain diagram for brittle steel

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ASTM Specification for Structural Shapes

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Part of detail drawing

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Part of erection drawing

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Responsibilities of the Structural Designer

• Safety– Safely support loads– Control deflection– Control vibrations

• Cost– Standard size members– Simple connections and details– Low cost maintenance

• Constructability– Learn detailing– Learnt fabrication– Learn erection of steel

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Building Code and Specifications

• Must refer to Building Code and Specifications• Local Building Code and Rules of

Municipalities• AISCS will be used for Structural steel

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Loads

• Accurate estimation• Worst possible combinations• If no local code use ASCE 7 (ANSI 58.1

Standards)

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Dead Loads

• Other are found in part 17 of AISCM

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Live Loads• Typical minimum uniform table (p.55)

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Live Loads

• Typical Concentrated Live Loads table 2.3 p55

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Impact• Impact factor (p. 56)

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Environmental Loads

• Snow• Rain• Wind• Earthquake

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Two Design Methods

• LRFD (Load and Resistance Factor Design)– Reduction factor φ– Nominal Strength Rn

– Computed factored force Ru

– φ Rn ≥ Ru

• ASD (Allowable Strength Design)– Safety factor Ω– Largest computed force Ra

– ≥ Ra

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Combined Loads