5.0 Overall System Overview
The helical dome module forms the primary crown structure of the 900‑meter tower. It integrates the structural dome frame, ring‑based load distribution system, multi‑service vertical piping core, and outrigger‑level distribution manifolds.
Primary Parameters
- Dome Height: 30.0 m
- Base Diameter: Ø24.0 m
- Apex Height Above Roof: 0 m (flush termination)
- Primary Material: Duplex Stainless Steel EN 1.4462
- Total Approx. Weight: 930,000 kg
5.1 Structural Dome System — Exploded Configuration
1. Apex Cap Assembly
- Diameter: Ø2.40 m
- Thickness: 50 mm
- Material: Duplex Stainless Steel EN 1.4462
- Function:
- Structural convergence node
- Transfers load into vertical ribs
- Sealed weather cap
2. Vertical Ribs (Typical)
- Quantity: 48
- Outer Diameter: Ø508 mm
- Wall Thickness: 25 mm
- Length: 30.0 m
- Function: Primary axial load‑bearing members transferring dome loads to base ring
3. Secondary Radial Rings
- Tube Diameter: Ø508 mm
- Wall Thickness: 25 mm
- Ring Diameter: Variable along height
- Quantity: 6
- Function: Lateral stabilization and circumferential load distribution
4. Helical Primary Truss System
- Tube Diameter: Ø508 mm
- Wall Thickness: 25 mm
- Helical Pitch: 7.5°
- Function:
- Provides torsional stiffness
- Dissipates aerodynamic loads
- Integrates with architectural twist
5. Perimeter Ring Beam (Base Ring)
- Outer Diameter: Ø24.0 m
- Inner Diameter: Ø22.2 m
- Thickness: 60 mm
- Function: Main load transfer interface to tower core; anchors dome structure
6. Diagonal Bracing (X‑Brace System)
- Tube Diameter: Ø323 mm
- Wall Thickness: 20 mm
- Length: Variable
- Function: Prevents buckling and enhances lateral rigidity
7. Connection Nodes (Typical)
- Node Diameter: Ø914 mm
- Fabrication: Cast + machined stainless steel
- Function: Multi‑member junctions and force redistribution
8. Dome Base Connection Plate
- Outer Diameter: Ø24.0 m
- Inner Diameter: Ø22.0 m
- Thickness: 60 mm
- Function: Bolted/welded interface to core; carries shear and moment loads
5.2 Dome Elevation Geometry
- Total Height: 30.0 m
- Profile Type: Hemispherical + elongated dome
- Grid System: Radial + helical hybrid
- Structural Apex: Pure compression node
Engineering Logic
- Geometry minimizes wind vortex formation
- Curvature ensures compressive load dominance
- Ring + rib system creates redundant load paths
5.3 Structural Weight Distribution
| Apex Cap | 12,500 kg |
|---|---|
| Vertical Ribs (48) | 96,000 kg |
| Secondary Rings (6) | 78,000 kg |
| Helical Trusses (24) | 320,000 kg |
| Perimeter Ring | 62,000 kg |
| Diagonal Bracing (96) | 98,000 kg |
| Connection Nodes (144) | 102,000 kg |
| Base Plate | 161,500 kg |
| Total | ≈ 930,000 kg |
5.4 Piping System — Overall Distribution
System Architecture
- Central vertical riser core
- Distribution at outrigger levels (every 20 stories)
- Circular routing via ring manifolds
Pipe Types & Specifications
| Water Supply | Ø219.1 mm × 12.5 mm — 2.0 MPa |
|---|---|
| Fire Suppression | Ø168.3 mm × 10.0 mm — 2.5 MPa |
| HVAC Chilled Supply | Ø114.3 mm × 8.0 mm — 1.6 MPa |
| HVAC Return | Ø114.3 mm × 8.0 mm — 1.6 MPa |
| Electrical Conduit Tray | 600×100 mm × 2.0 mm — N/A |
| Data Tray | 400×100 mm × 2.0 mm — N/A |
| Air Line | Ø88.9 mm × 6.0 mm — 1.0 MPa |
| Sewage Vent | Ø168.3 mm × 8.0 mm — N/A |
5.5 Typical Connection Node (Outrigger Level)
Connection Types
- Flanged pipe joints (bolted)
- Welded branch tees
- Multi‑service junction clusters
Engineering Logic
- Segregation prevents thermal interference
- Redundant routing ensures fail‑safe operation
5.6 Pipe Support & Hanger System
Pipe Hanger (Typical)
- Rod: M16 stainless steel (SS316)
- Clamp: SS316 with rubber liner
- Insulation: Elastomeric wrap
Tray Support
- Material: SS316
- Type: Welded bracket to truss
5.7 Support Spacing Schedule
| Water | Vertical: 3.0 m — Horizontal: 2.5 m |
|---|---|
| Fire | Vertical: 2.5 m — Horizontal: 2.0 m |
| HVAC | Vertical: 2.5 m — Horizontal: 2.0 m |
| Electrical | Vertical: 3.0 m — Horizontal: 2.0 m |
| Data | Vertical: 3.0 m — Horizontal: 2.0 m |
| Air | Vertical: 2.0 m — Horizontal: 1.5 m |
| Sewage | Vertical: 2.5 m — Horizontal: 2.0 m |
5.8 Material Specifications
| Pipes & Fittings | Duplex SS EN 1.4462 — ASTM A789/A790 |
|---|---|
| Trays & Supports | Stainless Steel 316L — ASTM A240 |
| Hangers | Stainless Steel 316 — ASTM A276 |
| Insulation | Closed‑cell elastomeric — ASTM C534 |
| Welding | Full penetration groove weld — EN ISO 15614‑1 |
5.9 Engineering Notes
- All piping systems routed through outrigger levels
- Dome designed for full aerodynamic exposure
- All welds full penetration unless specified
- Corrosion resistance critical due to elevation
- Fabrication tolerance: ±5 mm (shop)
- Installation tolerance: ±10 mm
5.10 Core Engineering Logic
Structural
- Dome acts as compression shell + truss hybrid
- Helical trusses counteract torsional wind loads
- Ring beams distribute forces evenly into core
Mechanical
- Vertical riser minimizes pressure loss
- Zonal distribution reduces redundancy load
- Fire system isolated for emergency integrity
Integration
- Structure + MEP integrated within same geometry
- Maximizes efficiency and reduces space usage
