Prestressed concrete

**1. Prestressed Concrete Concepts:**

– Prestressed concrete strengthens against tensile forces
– Tensioning of high-strength tendons improves performance
– Characteristics of high-strength concrete and steel
– Internal stresses are introduced in a planned manner
– Used in high-rise buildings, bridges, and industrial structures

**2. Pre-tensioned Concrete Concepts:**

– Tendons are tensioned before concrete casting
– Strong end-anchorage points are required
– Bond strength between concrete and tendons is critical
– Tendons generally form straight lines between anchorages
– Used for structural beams, floor slabs, and water tanks

**3. Post-tensioned Concrete Concepts:**

– Tendons are tensioned after concrete casting
– Tendons are encapsulated within protective sleeves
– Large forces are required to tension the tendons
– Different anchorage systems are used based on tendon composition
– Tendon encapsulation systems are made from plastic or steel

**4. Bonded and Unbonded Post-tensioning Concepts:**

– Bonded Post-tensioning:
– Tendons are permanently bonded to surrounding concrete
– Grouting protects tendons against corrosion
– Bundling of elements inside a single tendon duct is common
– Improves structural behaviors of the final concrete structure
– Used for efficient tendon installation and grouting processes

– Unbonded Post-tensioning:
– Tendons are not bonded to surrounding concrete
– Tendons are encapsulated within a greased sheath
– Reaction forces from tendon profiling counter loadings
– Ducts/sleeves can be profiled to any desired shape
– Beneficial for countering loadings applied to the structure

**5. Applications and Notable Structures:**

– Applications of Prestressed Concrete:
– Versatile in construction with high-strength steel and modern concrete
– Used in major design codes for various structures like buildings, bridges, dams, and pavements
– Utilized in stadiums, silos, tanks, and other civil structures

– Notable Structures:
– Examples include the Sydney Opera House, CN Tower, and the Gateway Bridge
– Also used in the construction of LNG tanks, nuclear reactor vessels, and blast-containment walls
– Various organizations worldwide promote best practices in prestressed concrete design and construction

This organization groups similar concepts together for a more structured and comprehensive understanding of prestressed concrete technology and its applications.https://en.wikipedia.org/wiki/Prestressed_concrete