A concrete column carries an axial load of $$450$$ $$kN$$ and a bending moment of $$60$$ $$kN$$-$$m$$ at its base. An isolated footing of size $$2m \times 3m$$ side along the plane of the bending moment is provided under the column. Centers of gravity of column and footing coincide. The net maximum and the minimum pressures in $$kN/{m^2}$$ on soil under the footing are respectively.

A prestressed concrete rectangular beam of size $$300\,\,mm \times 900\,\,mm$$ is prestressed with an intial prestressing force of $$700$$ $$kN$$ at an eccentricity of $$350$$ $$mm$$ at midspan. Stress at top due to prestress alone, in $$N/m{m^2}$$ is

A prestressed concrete rectangular beam of size $$300\,\,mm \times 900\,\,mm$$ is prestressed with an intial prestressing force of $$700$$ $$kN$$ at an eccentricity of $$350$$ $$mm$$ at midspan. Stress at top due to prestress alone, in $$N/m{m^2}$$ is

A prestressed concrete beam has a cross-section with the following properties: Area $$A = 46,000\,\,m{m^2},$$ $${\rm I} = 75.8 \times {10^7}\,\,m{m^4},$$ $${Y_{bottom}} = 244\,\,mm,$$ $${Y_{top}} = 156\,\,mm.$$ It is subjected to a prestressing force at an eccentricity $$'e'$$ so as to have a zero stress at the top fibre. The value of $$'e'$$ given by