Prestressed concrete
offers great technical advantages in comparison with other forms of construction,
such as reinforced concrete and steel.
In the case of
fully prestressed members, which are free from tensile stresses under working
loads, the cross-section is more eminently utilised
when compared with a reinforced concrete section which cracks under working
loads.
Within certain
limits, a permanent dead-load may be counteracted by increasing the
eccentricity of the prestressing force in a prestressed structural element,
thus effecting savings in the use of materials.
Prestressed concrete members possess improved resistance to shearing forces, because of compressive prestress,
which reduces the principal tensile stress.
The use of curved cables, particularly in long-span members, helps to reduce the shear forces developed at the support sections.
A prestressed concrete flexural member is stiffer under working loads than a reinforced concrete member of the same depth.
However, after the onset of cracking, the flexural behavior of a prestressed member is like that of a reinforced concrete member.
The use of high-strength concrete and steel in prestressed members results in lighter and slender members
than is possible with reinforced concrete.
The two structural features of prestressed concrete, namely high-strength concrete and freedom fromcracks, contributes to the improved durability of the structure under aggressive environmental conditions.
Prestressing of concrete improves the ability of the material for energy absorption under impact loads.
The ability to resist repeated working loads has been proved to be as good in prestressed as in reinforced concrete.
The economy of prestressed concrete is well established for long-span structures.
Prestressed concrete has considerable resilience due to its capacity for completely
recovering from substantial effects of overloading without undergoing any serious damage.
Due to the utilisation of concrete in the tension zone, an extra saving of 15 to 30 per cent in concrete is
possible in comparison with reinforced concrete.
The savings in steel are even higher, to 80 per cent, mainly due to the high permissible stresses allowed in the high-tensile wires.
Although there is considerable saving on the quantity of materials used in prestressed concrete members in comparison with reinforced
concrete members, it is not much significant due to the additional costs incurred for the high-strength concrete, high tensile steel, anchorages, and other hardware required to produce prestressed members.
However, there is an overall economy in using prestressed concrete, as the decrease in dead weight reduces the design loads
and the cost of foundations.
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which reduces the principal tensile stress.
The use of curved cables, particularly in long-span members, helps to reduce the shear forces developed at the support sections.
A prestressed concrete flexural member is stiffer under working loads than a reinforced concrete member of the same depth.
However, after the onset of cracking, the flexural behavior of a prestressed member is like that of a reinforced concrete member.
The use of high-strength concrete and steel in prestressed members results in lighter and slender members
than is possible with reinforced concrete.
The two structural features of prestressed concrete, namely high-strength concrete and freedom fromcracks, contributes to the improved durability of the structure under aggressive environmental conditions.
Prestressing of concrete improves the ability of the material for energy absorption under impact loads.
The ability to resist repeated working loads has been proved to be as good in prestressed as in reinforced concrete.
The economy of prestressed concrete is well established for long-span structures.
Prestressed concrete has considerable resilience due to its capacity for completely
recovering from substantial effects of overloading without undergoing any serious damage.
Due to the utilisation of concrete in the tension zone, an extra saving of 15 to 30 per cent in concrete is
possible in comparison with reinforced concrete.
The savings in steel are even higher, to 80 per cent, mainly due to the high permissible stresses allowed in the high-tensile wires.
Although there is considerable saving on the quantity of materials used in prestressed concrete members in comparison with reinforced
concrete members, it is not much significant due to the additional costs incurred for the high-strength concrete, high tensile steel, anchorages, and other hardware required to produce prestressed members.
However, there is an overall economy in using prestressed concrete, as the decrease in dead weight reduces the design loads
and the cost of foundations.
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