For flanged sections, m_ud = 0.08f_ckbd² assuming b = 0.5d and b_w = 0.25b, d³ = ((1200�106)/0.10x35x0.5)), d = 1000mm, b = 500mm, thickness of top flange = h_f = 0.2d = (0.2�10000) = 200mm, thickness of web = b_w = 0.25b = (0.25�500) = 125mm
Assuming neutral axis depth, x_u = hf = 200mm, m_u = 0.87f_pA_p (d-0.42xu), A_p = (m_u/0.87f_p (d-0.42xu)) = (1200�10⁶/0.87�1500(1000-0.42�200)) = 100³mm².

Curved cables are advantageous in reducing effective shear and toger with horizontal compressive prestress, reduce magnitude of principal tension and effect of shear is to induce tensile stresses on diagonal planes and prestressing is beneficial since it reduces magnitude of principal tensile stress in concrete.

In case of pre tensioned members, computations of transmission length at ends is of practical significance since support positions are influenced by bond and transmission length.

The area of high tensile and un tensioned reinforcement required to mobilize desired flexural strength is computed using force equilibrium at limit state of collapse and force equilibrium rar depends upon pressures exerted in different conditions.

The compression failure mode develops under concentric loading and this type of failure mode develops under concentric loads and section is considered to have failed when concrete strain ?0 reaches a value of 0.02.

Closely spaced spirals reinforcement increases ultimate load capacity of column due to confinement of concrete in core and spirals are particularly useful in increasing ductility of member and hence are preferred in high earthquake zones.

According to Indian standard code IS: 1343-1980, permissible unit bearing pressure on concrete after allowing for all losses is limited to: 0.48f_ci (A_br/A_pan) or 0.8 f_ci, f_ci = cube strength of concrete at transfer, A_br= bearing area, A_pan = punching area.

The design essentially consists of determining cross section area of member and required prestressing force to safely support axial tensile load conforming to limit state of serviceability and collapse.

In members with thin webs such as I and T sections nominal shear reinforcements have to be provided to prevent cracking due to variations in temperature provisions for design of shear reinforcements prescribed in British, American and Indian standard have been dealt with in case off structural concrete members subjected to torsion, shear stresses develop depending upon type of cross section and magnitude of torque and shear stresses in association with flexural stresses may give rise to principal tensile stress value of which when it exceeds tensile strength of concrete results in development of cracks on surface of member.

Assuming an anchor plate of size 50mm by 50mm, punching area A_pun = (50�50) = 2500mm², A_br = 10000mm², maximum permissible bearing pressure = 0.48fci(A_br/A_pun) or 0.8f_ci whichever is smaller, f_b = 0.48x30x(10000/2500)1/2 = 28.8n/mm² or (0.8�30) = 24n/mm2².