Advantages & Limitations of Prestressed Concrete

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.

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.