In a 10 m long simply-supported prestressed concrete beam, if prestressing force = P;eccentricity = e; area of cross-section = A; section modulus = Z; bending moment due to dead load = Mg; bending moment due to live load = Mq, the resultant stress due to dead load and live load at top fiber at mid-span is given by
1
\(\left( {\frac{P}{A} - \frac{{P.e}}{Z}} \right) + \left( {\frac{{{M_g}}}{Z}} \right) + \left( {\frac{{{M_q}}}{Z}} \right)\)
2
\(\left( {\frac{P}{A} + \frac{{P.e}}{Z}} \right) + \left( {\frac{{{M_g}}}{Z}} \right) + \left( {\frac{{{M_q}}}{Z}} \right)\)
3
\(\left( {\frac{P}{A} - \frac{{P.e}}{Z}} \right) - \left( {\frac{{{M_g}}}{Z}} \right) - \left( {\frac{{{M_q}}}{Z}} \right)\)
4
\(\left( {\frac{P}{A} + \frac{{P.e}}{Z}} \right) - \left( {\frac{{{M_g}}}{Z}} \right) - \left( {\frac{{{M_q}}}{Z}} \right)\)