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Over time, the prestress applied to concrete can decrease due to several factors, including creep, shrinkage of the concrete, relaxation of steel, and slip at the anchorages or seating of the tendons.

Effective prestress is the remaining prestress in a concrete member after accounting for immediate and time-dependent losses, such as elastic shortening, creep, and shrinkage of the concrete, and relaxation of the steel.

Pre-tensioning is a method of prestressing concrete where the tendons are tensioned before the concrete is placed. Once the concrete has achieved sufficient strength, the tendons are released, transferring the stress to the concrete.

Post-tensioning involves tensioning the tendons after the concrete has hardened. This is achieved by placing the tendons within ducts in the concrete, stressing them, and then anchoring them against the concrete.

Tendons are high-strength steel cables or bars used in prestressed concrete to impart tension to the concrete. They can be single wires, strands of multiple wires, or threaded bars.

Shrinkage is the reduction in volume of concrete as it loses moisture over time. This can also contribute to the loss of prestress in prestressed concrete structures.

Drift in the context of prestressed concrete refers to the lateral displacement or deviation from the initial position of a member due to the application of prestress. This is important to consider during design and construction.

The flexural strength of prestressed concrete is its capacity to resist bending moment. Prestressing can increase the flexural strength by reducing tensile stresses and controlling cracking under service loads.

The anchorage zone is the area of concrete where the prestress is transferred from the tendons to the concrete. This zone is subject to high local stresses and often requires reinforcement to prevent cracking.

Creep is the permanent and time-dependent deformation of concrete under sustained load. It can reduce the prestress in concrete members over time.

A bearing plate is used in prestressed concrete to distribute the prestress force from the tendon to a larger area of concrete, preventing localized crushing of the concrete.

Bursting forces are the tensile forces that occur perpendicular to the axis of the tendon's anchorage zones in prestressed concrete. They can cause cracks in the concrete and must be resisted by appropriate reinforcement.

Prestressed concrete is a form of concrete where internal stresses are introduced, typically by tensioning steel reinforcement, to counteract external loads applied during service, thus increasing the structural capacity and serviceability.