^{6}mm

^{4}and A = 6300 mm

^{2}. Take E

_{steel}= 200 GPa. All members have the same length of 1m. Determine the approximate deflection at mid-span.

## Respond

The top and bottom chord of the long truss shown below are CHS sections, and each has I = 31x10^{6} mm^{4} and A = 6300 mm^{2}. Take E_{steel} = 200 GPa. All members have the same length of 1m. Determine the approximate deflection at mid-span.

The correct answer is 26mm. The truss can be approximated to a beam. The second moment of Area of the 'beam' can be determined using parallel axis theorem allowing standard beam deflection equations applied for an approximate answer.