Aerodynamic & Wind Engineering Features (Exploded)

1. Design Basis & Wind Criteria

Governing Standards

• ISO 4354 — Wind actions on structures
• ASCE 7‑22 — Minimum Design Loads
• CTBUH Supertall Guidelines
• EN 1991‑1‑4 — Eurocode Wind Actions

Basic Wind Parameters

• Basic wind speed (10 m elevation): 45 m/s
• Exposure category: Open terrain (C/D transition)
• Top elevation wind speed (~900 m): 95–110 m/s

Design Wind Pressures

Dynamic Response Targets

• Peak acceleration (comfort): ≤ 0.015 g
• Ultimate drift ratio: H/500 → 1.8 m
• Service drift ratio: H/1000 → 0.9 m

2. Global Aerodynamic Form Strategy

Helical Geometry Parameters

• Total twist: 120°–180°
• Twist rate: 0.15°–0.25° per meter
• Floor rotation: 0.8°–1.5° per floor

Aerodynamic Benefits

• Reduces vortex shedding synchronization
• Breaks coherent wind excitation
• Lowers across‑wind response by 25–40%

Taper Strategy

Setback Intervals

• Every 120–180 m
• Floor plate shrinkage: 5–12%

3. Tuned Mass Damper (TMD) System — Fully Exploded

3.1 TMD Core Parameters

• Location: 850–890 m
• Mass ratio: 1.5–3%
• Building mass: ~800,000–1,000,000 tons
• TMD mass: 12,000–25,000 tons

3.2 Configuration

3.3 Frequency Tuning

• Target frequency: 0.08–0.15 Hz
• Hydraulic tuning range: ±15%

3.4 Damping System

• Viscous dampers: 8–16 units
• Stroke: ±1.5–2.5 m
• Damping coefficient: 5–15 MN·s/m

3.5 Performance

• Acceleration reduction: 30–50%
• Wind drift reduction: 20–30%

4. Secondary Damping Systems

4.1 Outrigger Dampers

• Installed at 300 m, 600 m, 850 m
• Type: Viscous / friction hybrid
• Force capacity: 10–25 MN

4.2 Structural Damping Connections

• Viscoelastic layers between core + outriggers
• Layers between mega‑columns + belt trusses
• Thickness: 25–75 mm

5. Wind Baffles & Pressure Modulation Systems

5.1 Façade Perforation Strategy

• Vent bands every 20–30 floors
• Opening ratio: 5–12%

5.2 Sky Voids / Blow‑Through Floors

• Located at ~250 m, ~500 m, ~750 m

5.3 Pressure Equalization

• Reduces peak suction forces
• Reduces internal pressure gradients
• Overall wind load reduction: 10–20%

6. Vortex Shedding Control

Strouhal Relationship

f = St × V / D

Mitigation Methods

• Helical twist
• Irregular floor plates
• Corner chamfering (2–5 m radius)
• Surface roughness modulation

7. Aerodynamic Façade Systems

7.1 Double‑Skin Façade

• Outer skin spacing: 1.0–2.5 m
• Ventilated cavity reduces pressure spikes

7.2 Corner Modifications

• Rounded or chamfered edges (3–8 m radius)

7.3 Vertical Fins

Fins disrupt flow separation and reduce vortex coherence.

8. Wind Tunnel Testing Protocol

Model Scales

• Rigid model: 1:400–1:600
• Aeroelastic model: 1:200–1:300

Testing Types

1. Boundary layer simulation
2. Pressure tap measurements
3. Dynamic response testing
4. Pedestrian wind comfort studies

Instrumentation

• Pressure taps: 500–1500 points
• Multi‑axis accelerometers
• Laser displacement sensors

9. Performance Targets

10. System Integration

Connected Systems

• Structural core & outriggers
• Façade engineering system
• Control systems (Section 15)
• Maintenance systems (Section 18)

Real-Time Monitoring

• Wind sensors every 100 m
• TMD position sensors (±5 mm accuracy)

11. Engineering Logic Summary

The aerodynamic strategy is multi-layered:

1. Helical + tapered form reduces excitation
2. Openings & vents reduce pressure loads
3. TMD + outrigger dampers absorb motion
4. Façade detailing disrupts flow patterns

Together, these ensure structural safety at extreme height, occupant comfort, and long-term fatigue resistance.