What Is Anchorage In Prestressed Concrete?
What Is Anchorage In Prestressed Concrete?
Anchorage in prestressed concrete consists of a bonded length of tendon, in direct contact with the concrete.
Prestressed concrete is a type of concrete that has been designed to withstand tension forces. It achieves this by using tendons, which are long, thin cables that are placed under tension within the concrete.
These tendons are typically stressed to a very high level, around 1000 MPa, which is much higher than the compressive strength of concrete.
In order to transfer the tension forces from the tendons to the concrete, the tendons must be anchored at their ends.
There are two main ways to anchor tendons in prestressed concrete: pretensioning and post-tensioning.
In pretensioned concrete, the tendons are anchored using a bonded length of tendon that is in direct contact with the concrete.
In post-tensioned concrete, an anchorage plate is used to transfer the tension forces from the tendons to the concrete.
The plate is typically much smaller than the area of concrete that is being compressed, so the stress is redistributed over a larger area according to St Venant’s Principle. This redistribution occurs within a region known as the anchorage zone.
Generally, components in a typical anchorage system may include a stressing end, anchorage wedges, anchorage plate, bearing plates, and base plates. Anchorage systems are used in the construction of bridges, dams and other large structures.
What Is Anchorage In Post Tensioning?
Anchorage is a part of a post tensioning system that helps secure tendons in concrete and connect them together.
It is a crucial component of prestressing systems because it transfers the stress force to the concrete after the tensioning process is finished.
The efficiency of the anchorage affects the durability of prestressed structures. Some of the key parts of an anchorage include the anchor head or plate, a removable grouting cap, an iron block or force transfer unit, bursting reinforcement, a deviation cone, and a duct coupler.
The prestressing force is applied to the strands and held in place by wedges in the anchor head, which sits on the force transfer unit embedded in the concrete.
The force transfer unit helps transmit the prestressing force into the concrete, while the deviation cone guides the strands from the anchor head to the duct.
What Is Stressing Anchorage?
Stressing Anchorage is a type of post-tensioning anchorage system that consists of wedge, anchor head, bearing plate, and spiral reinforcement.
It is commonly used in bonded post-tensioning with strand tendons in concrete structures and rock/soil anchoring structures.
CPS unbounded post-tensioning for slab on grade, which is becoming increasingly popular in industrial structures, can help to eliminate problems such as cracks, deformations, and curling caused by factors like temperature variations, heavy loads, and vehicle wheels abrasion.
This type of post-tensioning can also optimize the overall cost of a structure for the client. In addition to being safe and reliable, CPS Stressing Anchorage is also highly efficient, providing users with a trouble-free stressing system.
