Problem # p015b

Thermal Stress

Steel railroad rails are laid in sections, each having a length L = 12 m. Assume that they are laid at a temperature of 20°C with a gap of g = 4 mm.
  1. By how much can each section of length L expand before adjacent sections touch ?
  2. At what temperature would adjacent sections touch ?
  3. By how many degrees could the temperature increase further before the thermal stress in the rails reaches 200 MPa (=stress limit for steel) ?

Assume : α=12.0μm/(moC) and E = 200 GPa