Maximum strain at the level of compression steel for a doubly reinforced rectangular section having effective depth d, effective cover to compression steel as d' and neutral axis depth from compression face as xu will be
1
0.0035
2
\(0.0035\frac{{d'}}{{{x_u}}}\)
3
\(0.0035\left( {1 - \frac{{d'}}{{{x_u}}}} \right)\)
4
0.002