In this mode of failure, beam observes excess elongation of steel along with crushing of concrete this is because large amount of steel is provided in compression zone (greater than minimum steel reinforcement in tension zone).

Morsch has suggested a graphical version of strain compatibility method in which failure of compressive zone is assumed when extreme compressive fiber reaches a strain limit of 0.2%, many codes have recommended simplified procedures for calculating flexural strength of concrete sections which are reinforced with high tensile steel in tension zone.

Over reinforced section fails due to sudden crushing of concrete and this section observes small deflections and narrow cracks effective reinforcement due to which compressive strength of concrete and tensile strength of steel are increased up to a certain range of values n section is said to be over reinforced.

Consider a rectangular beam section subjected to a prestressing force of magnitude p and if section is subjected to prestressing force and live and dead load only n stress distribution across section is given by kern distance in form of upper and lower kern distance.

From moment due to live loads & dead loads, position of reinforcement is evaluated from relation e = 2M_d+M_L/2F,e = eccentricity, inoder to protect a member from collapsing suddenly after development of shear cracks a minimum shear reinforcement is provided this minimum shear reinforcement (A_s) is provided in form of stirrups which is obtained by satisfying following condition:
A_sv/b_sv = 0.4/0.8fy.

IS: 1343 code method is used for determining ultimate flexural strength of rectangular sections and T sections, all bending stresses and direct force shall remain compressive in any direction, in structures subjected to dynamic loading, under same circumstances on or structures a tensile stresses Ft may be allowed which is less than one tenth of maximum permissible compressive stresses.

The distribution of concrete strain is linear (plane section normal to axis remains plane even after bending), basic ory is applicable to all structural concrete sections wher reinforced or prestressed and some assumptions are made.

There are 6 steps involved in designing of a rectangular, prestressed concrete beam 6, moment (M₁), section modulus z, width & depth, area amount of steel required A_s, self weight of beam W_d, M_d, position of reinforcement.

In a prestressed concrete member, external type of loads is balanced by transverse component of suitable cable profile, on effect of loading net deformation increases stress, strain and length of tendon, extension of tendon = 2e?, increase in strain 2e?/l, increase in stress = 2e?/l E_c.

Consider a beam which is lying over ground provided with a tendon and is free from all external loads such that beam remains unaffected by any external bending moments, tension force and compression force act at same level when no external bending moments are acting over beam and tendon line (p line) or line in which compressive force is acting is known as pressure line and it is also known as P line or C line.