Pre tensioned or post tensioned members with bonded tendons develop bond stresses between steel and concrete when sections are subjected to transverse shear forces due to rate of change of moment along length of beam and in case of type 1 and 2 members, which are uncracked at service loads, flexural bond stresses developed are computed by considering complete section.

Due to presence of precompression, prestressed concrete is ideally suited for design of members subjected to axial tension and axial tension in a member depends upon direction of tension acting on a member and its reaction.

The pitch of spirals is limited to a range of 25 to 75mm and spiral should be well anchored by providing at least 11/2 extra turns when splicing rar than welding of spirals is used and pitches of spirals are limited to certain ranges.

The distribution of compressive stress in section at ultimate failure stage is considered and effective depth required is estimated by equating total ultimate moment with internal resisting angle.

The load moment interaction diagrams are more or less similar to prestressed columns those of reinforced columns expect that precompression exists in prestressed concrete columns and prestressed columns are much advantageous than any or elements which are replicable.

S = 4a_s(D_c ? d_s)/D_c² ?_s, a_s = cross sectional area of spiral, D_c = core of column measured to outside diameter of helix, d_s = diameter of spiral wire, ?s = ratio of volume of helical reinforcement.

In case of post tensioned members where prestress is transferred to concrete by means of external anchorages, bearing pressures develop behind anchorages have to be investigated and suitably controlled to prevent crushing failure of end block zone.

M_u = 0.36f_ckbx_u(d-0.42x_u) = 0.14f_ckbd², b = 0.5d, d³ = (m_u/0.14f_ck0.5) = (100�10⁶/0.15x50x0.5), d = 300mm, b = 150mm, x_u = (0.5�300) = 150mm for (x_u/d) = 0.5, f_pu = 0.87f_p, A_p = (m_u/0.87f_p(d-0.42x_u)) = (100�100⁶/0.87�1600(300-0.42�150)) = 300mm², adopt a section 150mm wide by 350mm deep with 300mm² of high tensile steel located at an effective depth of 300mm.

According to Indian standard code IS: 3370 1967 load factors against cracking and collapse should be not less than 1.2 and 2 respectively and IS: 3370 code is used for design factors of load factors.

The various codes recommend empirical relations to estimate ultimate shear resistance of section by considering flexure shear and web shear cracking modes and design shear resistance should exceeded ultimate shear due to transverse loads and if not, suitable transverse reinforcements are designed to resist balance shear force.