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

A cantilever beam of tubular section consists of 2 materials copper as outer cylinder and steel as inner cylinder. It is subjected to a temperature rise of $$20^\circ C$$ and $$\alpha_{copper}\;>\;\alpha_{steel}$$ the stresses developed in the tubes will be

The maximum value of Poisson's ratio for an elastic material is

In a linear elastic structural element