A frame tube structure, specifically the framed tube system, is a type of structural system for tall buildings that utilizes a stiff exterior shell to resist lateral loads like wind and earthquakes.
Understanding Framed Tube Systems
Framed tube systems are a popular design choice due to their efficiency and cost-effectiveness in constructing high-rise buildings. They are distinct from other tube systems, such as the tube-in-tube system, by relying on a robust exterior structure.
Key Characteristics
- Stiff Exterior Shell: The defining characteristic of a frame tube structure is its stiff exterior. This is achieved using closely spaced columns that are interconnected by deep spandrel beams.
- Interconnected Elements: The columns and spandrel beams are firmly joined together, acting as a single unit. This interconnected nature of the exterior shell significantly increases its stiffness.
How it Works
The closely spaced columns and deep spandrel beams form a strong, grid-like structure on the building's exterior. This grid acts as a large, hollow tube that resists bending and twisting forces, efficiently distributing lateral loads across the structure.
Framed Tube vs. Tube-in-Tube
The reference highlights a critical distinction:
- Framed Tube: Emphasizes a significantly stiffer exterior tube.
- Tube-in-Tube: May not have the same degree of stiffness in the exterior tube as a framed tube system.
| Feature | Framed Tube System | Tube-in-Tube System |
|---|---|---|
| Exterior Tube Stiffness | Very stiff, achieved by closely spaced columns and deep spandrel beams. | Relatively less stiff compared to framed tube system |
| Column Spacing | Closely spaced | May vary |
| Connection Type | Deep spandrel beams firmly connecting the columns | Different connection methods |
Practical Insights
- Efficiency: Framed tube structures allow for larger interior column-free spaces, which is beneficial for office layouts and other uses.
- Cost-Effectiveness: The efficient use of materials in the perimeter frame often leads to a more cost-effective high-rise structure compared to other systems.
