d = 40m, E_s = 210kn/mm², n = 4points, ? = 90?,
Length of wires = (?�40�1000/4) = 104?mm,
Extension at jack = (960/210�10³�10⁴?) = 144mm.

The type of tendon cold drawn steel wire to BS: 2691 are of two types: Pre-straightened (normal relaxation), Pre-straightened (low relaxation) both have a modulus of elasticity of 200kn/mm² having a percentage loss of prestress value of f_pi 5, 2 and f_pu 8.5, 3.

In case of pretensioned members, generally moist curing is resolved to in order to prevent shrinkage until time of transfer, magnitude of relative strain and stresses induced depend on concrete composition and surrounding environment to which composite member is exposed.

The loss of prestress due to shrinkage is obtained by multiplying shrinkage strain with modulus of elasticity of steel, ?f_s = E_sh�E_s, E_s = Residual shrinkage, E_s = modulus of elasticity of steel and light weight aggregates with low modulus of elasticity may lead to higher than normal concrete shrinkage where light weight aggregates are used, value of shrinkage should be increased by 50%.

b = 100mm, d = 300mm, E_s = 210kn/mm², E_c = 35n/mm²
?_e = E_s/E_c = (210/35) = 6n/mm².

A = 3�10⁴mm², p = (200�1200) = 240000n, e = 50mm,
Stress in concrete at level of steel: (240000/30000) = 8n/mm².

The shrinkage of concrete is influenced by type of cement and aggregates and method of curing used, rate and amount of shrinkage of structural member under ambient conditions will depend very much upon ratio of surface area to volume of member, as exchange of moisture between concrete and atmosphere must take place through surface.

In case of long line pre tensioning system, anchorage slip is much less in comparison with length of tensioned wires and hence it can be ignored for calculation of stresses, slip of anchorages, length of cable, cross-sectional area of cable, modulus of elasticity, prestressing force in cable are considered.

Anchorage slip is distance moved by friction wedges (in post tensioned members) after releasing jacks at ends of member and before wires get fixed perfectly in wedges, loss during anchoring which occurs with wedge type grips is normally allowed for on site by over-extending tendon in prestressing operation by amount of draw in before anchoring.

Loss of stress due to wobble effect, which depends upon local deviations in alignment of cable and wobble effect is also known as wave effect, friction coefficient values for wave effect k are 0.15 per 100m for normal conditions, 1.5 per 100m for thin walled ducts where heavy vibrations are encountered and in or adverse conditions.