Unbonded Construction

Definition

Unbonded construction is post-tensioned concrete construction in which the tendons are not grouted to the surrounding concrete.

Purpose

The purpose of unbonded construction is to allow the tendons to move independently of the concrete, providing flexibility and adjusting tension as needed to optimize structural performance.

Examples of Use

1. Parking Structures: Unbonded post-tensioning is used in parking garages to allow for large, open spaces without intermediate columns.
2. Bridges: In bridge construction, unbonded tendons help manage stresses and movements due to loads and temperature changes.
3. High-Rise Buildings: Unbonded post-tensioning is used to enhance the performance and reduce the thickness of concrete slabs in high-rise buildings.

Related Terms

• Post-Tensioning: A method of reinforcing concrete by tensioning steel tendons after the concrete has hardened.
• Bonded Construction: Post-tensioned concrete construction where tendons are grouted to the surrounding concrete.
• Prestressed Concrete: Concrete in which internal stresses are introduced to counteract potential tensile stresses in service.

Notes

• Advantages: Unbonded construction allows for easier inspection and replacement of tendons, as well as flexibility in design and construction.
• Maintenance: Regular monitoring and maintenance of unbonded tendons are important to ensure long-term structural performance.