There are two types of prestressed concrete based on the construction method:
I. Prestressed Concrete
II. Post-tensioned concrete that is bonded.
III. Post-tensioned concrete without bonding
Concrete that is pre-tensioned
This process involves first tensioning wires or tendons, and
then pouring concrete. It improves the bonding strength between the concrete
and tendon. Tensions are passed directly and the tendons are shielded from
corrosion as a result. When the concrete hardens, the tension in the anchored
and stretched tendon is transferred to the material. The tendon then attempts
to return to its initial length, but the concrete's bond resists it; as a
result, compressive force is induced in it.
Concrete with Bonded Post-tensioning
Comparable to pre-stressing, except that tendons are
tensioned after concrete is poured. After the member's tendon is positioned
appropriately, casting is completed. The tendons are tensioned against the
concrete by hydraulic jacks once the concrete hardens. Tendons are set in place
when they are suitably tensioned in accordance with design. Tension continues
when the jacks are removed, applying pressure to the concrete. This technique
is frequently employed to make monolithic slabs for large-scale home building
projects, where problems with expanding soil can occasionally arise. In
addition, post-tensioned concrete is utilized in bridge construction.
Post-tensioned Concrete Without Bond
Compared to bonded post-tensioned concrete, it differs
slightly. It permits unrestricted cable movement. Each tendon is encased in
plastic and lubricated for this purpose. Through anchors, the cables distribute
stress to the concrete. This has several benefits, such as: a. The capacity to
strain tendons before attempting repairs.
b. The capability to modify cables separately
There are also drawbacks, such as the possibility of one or
more cables distressing themselves and bursting out of the slab in the event of
damage.
0 Comments