Benefits and limitations of prestressing concrete
The prestressing of concrete offers various benefits relating to conventional reinforced concrete (RC) devoid of prestressing. A completely prestressed concrete member is generally dependent on compression throughout service life. This adjusts various imperfections of concrete.
Given below, various advantages of a pre-stressed concrete member.
A) Section stays un-cracked under service loads 1. Curtailment of steel corrosion * Strength is improved. 2. Full section is applied * Greater moment of inertia (greater stiffness) 3. A smaller amount of deformations (better serviceability). 4. Rise in shear capacity 5. Appropriate for being utilized in pressure vessels, liquid retaining structures.
* Enhanced performance (resilience) under dynamic and fatigue loading.
B) High span-to-depth ratios 1. Higher spans are achieved with prestressing (bridges, buildings with large column-free spaces)
2. Standard values of span-to-depth ratios in slabs are provided herewith.
For the similar span, less depth relating to RC member. * Decline in self weight * More visual appeal because of slender sections * More economical sections.
C) Best fit for precast construction The benefits of precast are given below :-
* Quick construction * Superior quality control * Less maintenance * Ideal for repetitive construction * Multiple application of formwork
Though, prestressing offers several benefits, there are some negative aspects also:-
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* Prestressing requires competent technology. So, the process is not so easy as compared to reinforced concrete. * As high strength materials are used in prestressing, so they are quite expensive.
* There is extra cost in supporting equipments. * Prestressing requires thorough quality control and examination.
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