A column section as indicated in the given figure is loaded with a concentrated load at a point 'F' so as to produce maximum bending stress due to eccentricities about xx axis and yy axis as 5 t/m² and 8 t/m² respectively. If the direct stress due to loading is 15 t/m² (compressive), then the intensity of resultant stress at the corner 'B' of the column section is