Floor System Module — Structural Specification

2.1 System Overview

The Floor System Module is a radial space‑frame diaphragm structure that connects the Central Stainless Steel Core (Ø24,000 mm) to the Helical Exterior Mega Frame (Ø220,000 mm).

Primary Functions

• Transfers gravity loads (dead + live) to both core and perimeter
• Acts as a rigid diaphragm for lateral load distribution
• Provides torsional stability for the helical tower geometry
• Integrates structural and architectural floor systems

2.2 Global Module Geometry

2.3 Structural Grid Configuration

Radial System

• 12 Primary Radial Trusses
  • Spaced at 30° intervals
  • Span: ~10,500 mm
• 24 Secondary Radial Members
  • Located between primary trusses
  • Provide deck support and load distribution

Circumferential System

• Three continuous ring beams:
  • Upper diaphragm ring
  • Mid‑depth ring
  • Lower ring

Diaphragm Behavior

• Acts as a rigid plate under lateral loads
• Transfers shear to core and perimeter frame
• Prevents differential rotation between systems

2.4 Component Breakdown (Exploded System)

1. Finished Floor System

• Thickness varies (architectural)
• Non‑structural load transfer layer

2. Structural Floor Deck

• Composite steel deck
• Thickness: 1.2 mm
• Material: 316L Stainless Steel
• Distributes load to secondary members

3. Secondary Radial Members

• Section: CHS Ø406 mm
• Wall thickness: 20 mm
• Length: ~5,000 mm
• Quantity: 24 per module
• Function: deck support and load transfer to primary trusses

4. Floor Diaphragm Ring (Upper)

• Section: CHS Ø1,200 mm
• Thickness: 25 mm
• Continuous circumferential ring
• Function: primary diaphragm tension/compression ring

5. Primary Radial Trusses

• Section: CHS Ø1,200 mm
• Wall thickness: 50 mm
• Length: 10,500 mm
• Quantity: 12
• Main load‑carrying elements

6. Circumferential Ring Beam (Mid)

• Section: CHS Ø1,500 mm
• Thickness: 40 mm
• Provides torsional stiffness and load redistribution

7. Diagonal Bracing (Under Floor)

• Section: CHS Ø324 mm
• Thickness: 16 mm
• Quantity: 24
• Stabilizes radial trusses and prevents buckling

8. Circumferential Ring Beam (Lower)

• Section: CHS Ø1,500 mm
• Thickness: 40 mm
• Bottom chord stabilization

9. Ring Stiffener Plates

• Plate thickness: 25 mm
• Located at node intersections
• Prevent local buckling and distribute node forces

10. Core Connection Assembly

• Flange + stiffener system
• Hybrid welded + bolted connection
• Core shell interface thickness: 120 mm
• Transfers axial loads, shear forces, and bending moments

11. Perimeter Frame Connection

• Node + gusset system
• Fully welded + bolted
• Connects floor module to exterior mega frame

2.5 Connection Engineering Details

Radial Truss → Core

• Core shell thickness: 120 mm
• Stiffener plates: 50 mm
• Bolt system: M64 bolts (Grade 8.8)
• Full penetration welds

Radial Truss → Ring Beam

• Radial truss: Ø1,200 mm
• Ring beam: Ø1,500 mm
• Gusset plates: 40 mm
• Bolting: M64 bolts (Grade 8.8)

2.6 Material Specification

2.7 Structural Performance Criteria

2.8 Engineering Logic

Load Path

1. Floor loads → deck
2. Deck → secondary members
3. Secondary → primary trusses
4. Primary trusses → core and perimeter mega frame

Lateral Load Behavior

• Floor acts as rigid diaphragm
• Transfers wind and seismic shear to core (primary) and exterior frame (secondary)

Torsional Stability

• Circular geometry + ring beams resist twisting
• Maintains geometric integrity of helical form

Redundancy Strategy

• Multiple load paths: radial, circumferential, diagonal
• Failure of one element → redistributed forces

2.9 Fabrication & Tolerances

2.10 Module Weight

Approximate weight per module: ≈ 85,000 kg

2.11 Summary

The Floor System Module is a high‑performance radial space frame engineered to handle extreme loads in a 900‑meter helical tower. It provides rigid diaphragm action, torsional stability, modular constructability, and long‑term durability exceeding 150 years.