The secondary reinforcements can be bent if suitable packets are provided behind anchorages and after operations of prestressing are done, pocket is filled with mortar, In case of uncracked members bond stresses are computed by considering complete section, which is effective.

The magnitude of average bond stress is considerably less than maximum local bond stress but according to investigations of R_os, average bond stress varied from 3.25 to 1n/mm² for round wires of 1.5 to 5mm diameter in case of wires initially tensioned to a stress of 1200n/mm² and tensile stress shall not be allowed at any loading stage up to cracking in case of members assembled out of precast blocks.

The term i_w is thickness of web and this is used in problems of end zone cracking in pretensioned I beams, on applying compressive forces of equal magnitude along same line tensile forces can be balanced.

The magnitude of bond stresses developed between concrete and steel and its variation in transfer zone of pretensioned beam, deformation of concrete shrinkage depends on environmental conditions, age of concrete, size of concrete, concrete composition, etc.

The stress in a steel wire gradually increases from zero at end of beam to 100 percent of effective stresses at end of transmission length, after beam is placed slab is casted and different rates of shrinkage imposed forces are developed because a moment is induced if slab is not at neutral axis of section.

The transmission length mainly depends on 4 factors, diameter of wire, surface characteristics of wire, co-efficient of friction between steel and concrete, elastic properties of steel and concrete.

Cold rolling of elliptical or rhombic shallow indentations on surface of wires and hot rolling of oblique transverse ribs on wires which are subsequently heat treated methods of obtaining shear bond.

A time dependant formation of concrete is termed as creep, this deformation is seen due to loadings and applied stress or strain failures and main effects of creep are it decreases effects due to shrinkage strain; re is a mutual transfer of loads from beam to composite section.

When bond stress in zero, steel and concrete reach ir maximum values of stresses with uniform stress distribution in this section, bond lengths recommended in German specifications are compiled in drawn steel of diameter 3 to 8 and bond length 600mm.

A number of cases of cracks developed in precast pretensioned members are reported by foundation and it has been found that method of distributing tendons at ends have a greater influence on end zone cracking.