9.1 Overall Structural Assembly Logic
The tower is composed of modular ring‑based structural assemblies stacked vertically and connected through high‑strength bolted and welded joints. The assembly integrates the dome crown, outrigger and belt truss systems, radial floor truss rings, prefabricated floor modules, the central reinforced core, magnetic bearing interface, and the foundation anchoring system.
Engineering Principle
- Primary Load Path: Floor → Radial Trusses → Ring Beam → Core + Outriggers → Foundation
- Lateral Stability: Belt trusses + radial stiffness + core interaction
- Torsional Resistance: Continuous ring geometry + symmetric node distribution
9.2 Typical Floor Module — Structural Data
| Module Diameter (OD) | 22,000 mm |
|---|---|
| Module Height | 4,500 mm |
| Deck Thickness | 60 mm (composite slab) |
| Total Module Weight | ≈ 425,000 kg |
Component Breakdown
- Composite floor deck panel
- Secondary radial members
- Primary radial trusses
- Perimeter ring beam
- Node connections
- Vertical core interface ring
Engineering Logic
- Radial trusses convert distributed loads into circumferential compression
- Ring beam acts as a closed structural loop preventing deformation
- Core connection provides vertical load continuity and lateral stiffness coupling
9.3 Node Connection System (Typical)
Connection Types
- Radial truss node
- Vertical member node
- Belt truss node
- Core shell interface
- Gusset plate junction
Connection Specifications
| Truss Connections | Duplex Stainless Steel — M64 (Grade 8.8) — Qty 8 |
|---|---|
| Vertical Nodes | Duplex Stainless Steel — M64 — Qty 8 |
| Belt Truss Nodes | Duplex Stainless Steel — M64 — Qty 8 |
| Core Shell Nodes | Duplex Stainless Steel — M64 — Qty 12 |
| Gusset Plates | Duplex Stainless Steel — No fasteners |
Engineering Logic
- Nodes act as multi‑axis load transfer hubs
- Load distribution is radial and vertical simultaneously
- Redundant bolt groups ensure fail‑safe behavior
9.4 Foundation / Base Connection
Geometry
| Base Diameter | 24,000 mm |
|---|---|
| Anchor Bolt Circle | 22,000 mm |
| Anchor Bolt Count | 48 |
| Bolt Specification | M64 (Grade 8.8) |
| Base Plate Thickness | 60 mm |
Components
- Base connection plate
- Vertical anchor bolts
- Leveling nuts
- Ring beam interface
- Deep foundation piles
Engineering Logic
- Loads distributed radially into pile system
- Anchor circle aligns with structural ring geometry
- Prevents overturning via tension/compression bolt pairs
9.5 Fastener System Overview
Primary Fastener Types
- Hex bolts (M64, Grade 8.8)
- Hex nuts
- Flat washers
- Spring washers
- High‑strength anchor bolts
- Chemical anchors
- Threaded rods (M16–M24)
- Lock nuts
- Socket cap screws (M20)
- Self‑locking nuts
- Rivets (Ø8 mm, SS316)
9.6 Fastener Material Specification
| Material | Duplex Stainless Steel (EN 1.4462) |
|---|---|
| Standard | ISO 898 / ASTM A193 |
| Corrosion Resistance | Marine‑grade |
| Design Life | 150 years |
| Protection | Passivated finish |
9.7 Bolt Connection Design
Typical Bolt Assembly
- Bolt: M64
- Washer: Flat + spring
- Plate interface: Structural steel
Performance Values
- Tightening Torque: 900 N·m
- Preload Force: ≈ 310 kN per bolt
Engineering Logic
- Preload ensures friction‑based load transfer
- Prevents slip under cyclic wind/seismic loads
- Spring washer maintains tension under vibration
9.8 Welded Connection Standards
Groove Weld (Primary Structural)
- Type: Full Penetration Groove Weld
- Groove Angle: 30°
- Root Gap: 3 mm
- Weld Depth: 25 mm typical
- Minimum Plate Thickness: 20 mm
Process
- Method: GTAW / SMAW
- Filler: ER2209 (Duplex compatible)
- Standards: EN ISO 15614 / AWS D1.6
Engineering Logic
- Full penetration weld eliminates weak interface planes
- Duplex filler maintains corrosion and fatigue resistance
9.9 Module Lifting & Handling
Lifting Geometry
| Module Diameter | 22,000 mm |
|---|---|
| Module Weight | ≈ 425,000 kg |
| Lifting Points | 8 |
| Capacity per Point | 150,000 kg |
| Safety Factor | 5:1 |
Components
- Lifting eyes
- Stainless steel brackets
- Radial sling attachment points
- Temporary spreader beam
Engineering Logic
- Load evenly distributed to prevent ring distortion
- Redundant lifting points ensure safe hoisting
9.10 Assembly Sequence (Typical Floor)
- Install primary radial trusses
- Install secondary radial members
- Install perimeter ring beam
- Place composite floor deck panels
- Connect to central core
- Integrate with upper module
Key Principle
- Assembly proceeds from structural skeleton → enclosure → integration
- Ensures stability at every stage
9.11 Assembly Tolerances
| Module Diameter | ±10 mm |
|---|---|
| Module Height | ±5 mm |
| Verticality (per 100 m) | ≤10 mm |
| Radial Alignment | ±5 mm |
| Bolt Hole Position | ±1 mm |
| Weld Gap | ≤2 mm |
Engineering Logic
- Tight tolerances maintain global alignment over 900 m height
- Prevents cumulative geometric drift
9.12 Fastener Quantities (Approx.)
| Hex Bolts (M64) | ~1,250,000 |
|---|---|
| Anchor Bolts (M64) | ~4,800 |
| Socket Cap Screws (M20) | ~320,000 |
| Misc. Fasteners | ~2,100,000 |
| Total Fastener Count | ≈ 3.67 million units |
9.13 System Engineering Summary
Structural Philosophy
- Modular prefabrication
- High redundancy connections
- Hybrid bolted + welded system
Performance Objectives
- Long‑term durability (150+ years)
- High fatigue resistance
- Corrosion resistance
- Rapid assembly capability
Critical Design Drivers
- Wind‑induced oscillation resistance
- Thermal expansion compatibility
- Precision alignment over extreme height
