Something for all my Bridge Engineering students.
For the simply supported pre-stressed beam shown above, calculate the maximum allowable length (in meters) if the maximum tensile stresses due to the unfactored dead weight are limited to 1N/mm2.
Take the density of concrete to be 24kN/m3 and the centroidal axis is at mid-height of the section.Please ignore any reliving effects or the action of live loads
Hopefully you got an answer of 36.7m, which is less than the transportable limit of 40m. If you got anything other than 36.7m please read the solution. week13 solution