The maximum positive and negative moments due to live and dead load moments at various sections of member are calculated and hence computing range of moment which is obtained as difference of maximum and minimum moments at a cross section, M_t = M_max-M_min In design of statically indeterminate prestressed concrete structures involves computation of maximum and minimum moments at various cross sections of members.

The problem of excessive frictional losses can be tackles by reducing curvature of cables housed in members of variable depth and also by temporarily overstressing tendons from both ends.

In statistically indeterminate prestressed concrete structures it is possible to make simple modification to Predetermined tendon profile without altering pressure line I members this is an important property of continuous prestressed beams first enunciated by Guyon as follows: In a continuous prestressed beam, if tendon profile is displaced vertically any of intermediate supports by any amount but without altering its intrinsic shape between supports, resultant line of thrust is unchanged.

The data available for purpose of design is overall shape of structure and loading conditions and computations of maximum and minimum live load bending moments require a knowledge of stiffness of members of frame and moments and thrusts determined by assuming a suitable stiffness ratio by normal methods of structural analysis.

If partial redistribution takes place due to constraints imposed by limited hinge rotations, ultimate strength of structure lies in between upper limit above and lower limit corresponding to computations based on linear elastic ory.

The bending moments are more evenly distributed between centre of span and supports of member?s leads to increased stability and in continuous prestresssed structures, deflections are comparatively small as compared to simply supported span.

Continuity in prestressed concrete construction is achieved by using curved or straight cables which are continuous over several spans and it is also possible to develop continuity between two precast beams by using cap cables alternatively short straight tendon may be used over supports to develop continuity between two precast prestressed beams.

The resultant thrust line in a two span continuous beam prestressed by a parabolic cable with zero eccentricity at all supports and if tendon profile is made to coincide with resultant thrust line, redundant reactions are completely eliminated and cable may be considered as concordant.

Due to large deformations at critical sections in a statically indeterminate structure a concentration of curvature builds up over a few clearly defined short length of member, such as interior supports and midspan points of a continuous beam and se plastic zones are idealized as hinges at which a rotation is considered to take place.

The resultant moment at a section of an indeterminate prestressed structure is sum of primarily and secondary moments:
Resultant moment = (Determinate moment +Secondary moment).