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create ppt slides based on this: Slide 1 Title: Introduction to Structural Engineering Subtitle: CE470 – Structural Steel Design Content: Course focus: Design of steel structures Topics: Structural members, connections, loads, and design methods Objective: Understand the systematic process of structural design Slide 2 Title: The Structural Design Process Content: Systematic and iterative process Involves multiple stakeholders: Owner Architect Engineer Fabricator/Contractor Building Official Slide 3 Title: Key Steps in Structural Design Content: Identify use and occupancy Develop architectural plans Identify structural framework Estimate loads Analyze structure Design members and connections Verify design Fabricate and erect Inspect and approve Slide 4 Title: Roles and Responsibilities Content: Owner: Decides use, approves plans Architect: Ensures functionality and aesthetics Engineer: Ensures safety and serviceability Fabricator: Fabricates members economically Contractor: Erects structure in the field Building Official: Ensures code compliance Slide 5 Title: Structural Design: Material Choices Content: Materials used in construction: Steel Reinforced concrete Steel-concrete composite Course focus: Steel structures Slide 6 Title: Structural Framing Systems Content: Types of frames: Moment-resisting frames Braced frames Dual frames Shear wall frames Course focus: Braced and moment-resisting frames Slide 7 Title: Design Approach Content: Compare material + framing alternatives Choose most efficient and economical design Design individual members and connections Slide 8 Title: Example: Four-Story Office Building Content: Location: West Lafayette Layout: 2 bays (25 ft) N-S 3 bays (35 ft) E-W Roof truss system Slide 9 Title: Structural Frames in N-S Direction Content: 4 braced frames All connections: pin/hinge type Diagonal bracing for stability Resists gravity and lateral loads Slide 10 Title: Structural Frames in E-W Direction Content: 3 moment frames All connections: fixed/moment type No bracing needed Resists gravity and lateral loads Slide 11 Title: Types of Structural Members Content: Tension member – axial tension only Column – axial compression only Tension/compression member – both axial forces Beam – flexural loads only (shear + moment) Beam-column – combined axial + flexural loads Slide 12 Title: Member Behavior in Trusses Content: All members connected with pins Loads applied at joints Members carry axial forces only (tension/compression) Slide 13 Title: Member Behavior in Braced Frames Content: Beams: flexural loads only Columns: axial compression only Braces: tension/compression only Slide 14 Title: Member Behavior in Moment Frames Content: Beams: flexural loads only Beam-columns: combined axial + flexural loads Slide 15 Title: Types of Structural Connections Content: Truss/bracing connections – transfer axial forces Simple shear connections – transfer shear only Fully-restrained moment connections – transfer shear + moment Partially-restrained connections – partial moment transfer Slide 16 Title: Connection Methods: Bolts Content: Used for plates in same plane High-strength steel bolts Holes drilled, bolts secured with nuts Easy field assembly Slide 17 Title: Connection Methods: Welds Content: Electric arc melts base metal + electrode Forms continuous joint upon cooling Can connect plates in different planes Requires skilled welders Slide 18 Title: Example: Truss Connection Content: Members welded to gusset plate Axial forces transferred through gusset Bolted alternatives possible Slide 19 Title: Example: Shear Connection Content: Double-angle bolted to beam web and column flange Transfers shear only Economical field assembly Slide 20 Title: Example: Moment Connection Content: Beam flanges welded to column (full penetration) Beam web bolted to shear tab Transfers both shear and moment Slide 21 Title: Types of Structural Loads Content: Dead loads (D) – permanent Live loads (L) – variable Wind loads (W) – lateral pressure/suction Snow loads (S) – vertical, seasonal Roof live loads (Lr) – maintenance, equipment Slide 22 Title: Dead Loads (D) Content: Weight of all permanent materials Estimated from material densities Examples: Steel frame: 60–75 lb/ft² Concrete frame: 110–130 lb/ft² Slide 23 Title: Live Loads (L) Content: Due to occupancy and use Values from ASCE/SEI 7-10 Can be uniform or concentrated May be reduced for large floor areas Slide 24 Title: Live Load Reduction Content: Applied when K L L A T ≥ 400 ft 2 K LL ​ A T ​ ≥400 ft 2 Formula: L = L 0 ( 0.25 + 15 K L L A T ) L=L 0 ​ (0.25+ K LL ​ A T ​ ​ 15 ​ ) Minimum limits apply Slide 25 Title: Live Load Element Factor K L L K LL ​ Content: Interior columns: 4.0 Edge columns: 3.0 Corner columns/edge beams: 2.0 Others: 1.0 Slide 26 Title: Example: Live Load Calculation (Step I) Content: Determine tributary areas Identify K L L K LL ​ values Calculate reduction factor L / L 0 L/L 0 ​ Slide 27 Title: Example: Live Load Calculation (Step II) Content: Calculate distributed loads on beams Example: w = 0.85 × 50 × 25 / 1000 = 1.06 kip/ft w=0.85×50×25/1000=1.06 kip/ft Slide 28 Title: Example: Live Load Calculation (Step III) Content: Estimate concentrated loads on columns From orthogonal beams: 17.34 kips, 28.125 kips Slide 29 Title: Example: Live Load Calculation (Step IV) Content: Check column loads directly Compare with beam-based results Use larger values for design Slide 30 Title: Roof Live Loads (Lr) Content: Formula: L r = 20 R 1 R 2 L r ​ =20R 1 ​ R 2 ​ (psf) Limits: 12 ≤ L r ≤ 20 12≤L r ​ ≤20 R 1 R 1 ​ depends on tributary area R 2 R 2 ​ depends on roof slope Slide 31 Title: Wind Loads (W) Content: Act as pressure/suction on surfaces Cause lateral loads and uplift Design methods: Simplified Analytical Wind tunnel Slide 32 Title: Wind Velocity Pressure Content: Formula: q z = 0.00256 K z K z t K d V 2 q z ​ =0.00256K z ​ K zt ​ K d ​ V 2 For West Lafayette: V = 115 mph V=115 mph q z = 28.78 K z q z ​ =28.78K z ​ psf Slide 33 Title: Wind Pressure on Buildings Content: Formula: p = q G C p − q i ( G C p i ) p=qGC p ​ −q i ​ (GC pi ​ ) G = 0.85 G=0.85 (gust factor) C p C p ​ : external coefficient G C p i GC pi ​ : internal coefficient Slide 34 Title: Example: Wind Load Calculation Content: Wind direction: E-W C p C p ​ values: Windward: +0.8 Leeward: -0.3 Side: -0.7 Slide 35 Title: Example: External Wind Pressures Content: Windward: 19.57 K z 19.57K z ​ psf (toward) Leeward: 6.38 6.38 psf (away) Side: 14.90 14.90 psf (away) Slide 36 Title: Example: Internal Wind Pressures Content: Enclosed building: G C p i = ± 0.18 GC pi ​ =±0.18 q i ( G C p i ) = 4.51 q i ​ (GC pi ​ )=4.51 psf (toward/away) Slide 37 Title: Load and Resistance Factor Design (LRFD) Content: AISC-recommended method Uses factored loads and resistance factors Ensures safety and reliability Slide 38 Title: LRFD Load Combinations Content: Common combinations: 1.4 D 1.4D 1.2 D + 1.6 L + 0.5 ( L r or S ) 1.2D+1.6L+0.5(L r ​ or S) 1.2 D + 1.6 ( L r or S ) + ( 0.5 L or 0.5 W ) 1.2D+1.6(L r ​ or S)+(0.5L or 0.5W) 1.2 D + 1.0 W + 0.5 L + 0.5 ( L r or S ) 1.2D+1.0W+0.5L+0.5(L r ​ or S) 0.9 D + 1.0 W 0.9D+1.0W Slide 39 Title: LRFD Design Inequality Content: Design requirement: ϕ R n ≥ ∑ γ i Q i ϕR n ​ ≥∑γ i ​ Q i ​ ϕ ϕ: resistance factor R n R n ​ : nominal strength γ i γ i ​ : load factor Q i Q i ​ : nominal load Slide 40 Title: Summary & Key Takeaways Content: Structural design is collaborative Members and connections behave differently under loads Loads must be estimated using codes (ASCE 7) LRFD ensures safe and economical design Next: Detailed design of steel members in CE470