Bridges

Sema Essien, Civil Engineer, and Program Manager at DC Water says (Archive):

  “ As a civil engineer, I have never taken the curve of the earth into any calculation. There is no calculation for the curve of the earth. You take two points and you build toward each other. In the middle may be some additional elevation of the roadway on the bridge to account for pitch, drainage of water and the overall stability (as most suspension bridges), but the ends are pretty much surveyed to be two level points measured at an elevation height above sea level. The footings of the bridge must be level or the design will be flawed. So there’s no curve. ”

Sema Essien's name can be found with a search in the DC Water 2018 Org Chart and a DC Water 2019 Employee Roster (p.4).