Jacking Force

Definition

Jacking force is the temporary force exerted by a device that introduces tension into prestressing tendons in prestressed concrete.

Purpose

The purpose of jacking force is to apply the necessary tension to prestressing tendons in concrete construction, ensuring that the concrete can withstand higher loads and stresses. This process enhances the strength, durability, and performance of concrete structures such as bridges, buildings, and parking structures.

Examples of Use

1. Bridge Construction: In the construction of a prestressed concrete bridge, jacking force is applied to tension the tendons before the concrete is cast, resulting in a structure that can support heavier loads and span longer distances.
2. High-Rise Buildings: Jacking force is used to prestress concrete beams and floors in high-rise buildings, increasing their load-bearing capacity and reducing the need for additional supports.
3. Parking Structures: In multi-level parking garages, jacking force is applied to prestress the concrete slabs, ensuring they can handle the weight of multiple vehicles and resist cracking.

Related Terms

• Prestressed Concrete: Concrete in which internal stresses are introduced to counteract tensile stresses, improving performance under load.
• Tendons: High-strength steel cables or rods used in prestressing concrete.
• Post-Tensioning: A method of prestressing where tendons are tensioned after the concrete has been cast and cured.
• Pre-Tensioning: A method of prestressing where tendons are tensioned before the concrete is cast.

Notes

When applying jacking force, it is essential to monitor the tensioning process carefully to avoid over-tensioning or under-tensioning, both of which can compromise the structural integrity of the concrete. The equipment used for jacking must be calibrated and maintained to ensure accurate force application.