Tension steel in one layer or more.Compression steel in one layer. Tensile steel assumed yielding but in analysis problems, this may be untrue Compression steel may yield or not. Strain expressions are derived from strain compatibility of plane sections (use of similar triangles). If compression and tension steel have yielded, OK continue, perform strain checks and compute nominal moment If compression steel has not yielded, express unknown stress block depth and compression steel stress in terms of neutral axis depth c and solve resulting quadratic equation. Perform strain checks and compute the nominal moment.