Civil Notes Logo AboutCivil Logo Advantages of Prestressing, Limitations of prestressed concrete

Advantages of Prestressed Concrete

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The prestressing of concrete has several advantages as compared to traditional reinforced concrete (RC) without prestressing. A fully prestressed concrete member is usually subjected to compression during service life. This rectifies several deficiencies of concrete. The following text broadly mentions the advantages of a pre-stressed concrete member with an equivalent RC member. For each effect, the benefits are listed.

A) Section remains un-cracked under service loads

  1. Reduction of steel corrosion
    • Increase in durability.
  2. Full section is utilized
    • Higher moment of inertia (higher stiffness)
  3. Less deformations (improved serviceability).
  4. Increase in shear capacity
  5. Suitable for use in pressure vessels, liquid retaining structures.
    • Improved performance (resilience) under dynamic and fatigue loading.

B) High span-to-depth ratios

  1. Larger spans possible with prestressing (bridges, buildings with large column-free spaces)
  2. Typical values of span-to-depth ratios in slabs are given below.

For the same span, less depth compared to RC member.

  • Reduction in self weight
  • More esthetic appeal due to slender sections
  • More economical sections.

C) Suitable for precast construction The advantages of precast construction are as follows.

  • Rapid construction
  • Better quality control
  • Reduced maintenance
  • Suitable for repetitive construction
  • Multiple use of formwork
  1. Reduction of formwork
  • Availability of standard shapes.

The following figure shows the common types of precast sections.

Limitations of Prestressing

Although prestressing has advantages, some aspects need to be carefully addressed.

  • Prestressing needs skilled technology. Hence, it is not as common as reinforced concrete.
  • The use of high strength materials is costly.
  • There is additional cost in auxiliary equipments.
  • There is need for quality control and inspection.
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