Two-wheel loads 80 kN and 200 kN respectively spaced 2 m apart, move on a girder of span 16 m. Any wheel load can lead the other. The maximum negative shear force at a section 4 m from the left end will be

it is given that any load can lead the other, considering 200 kN is leading to get maximum shear force.

maximum shear force at the section = load value × coordinates of ILD below the load.

ILD for section C (4m from the left support) is shown below,

As we can see the coordinate of ILD below 80 kN load is calculated as 2/16.

The coordinate of ILD below 120 kN load is calculated as 12/16.

Now, the maximum negative shear force at section is given by,

SF = \( - \left( {80 \times \frac{2}{{16}}} \right) - \left( {200 \times \frac{4}{{16}}} \right) = - 60\;kN.\)