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).
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).
Curved bridges
https://www.quora.com/Why-is-the-curvation-of-earth-never-in-the-calculation-of-very-long-bridges
Q: Why is the curvation of earth never [used] in the calculation of very long bridges?
A: The reason is because there is no calculation. If there were, it would be in a formula, but we never calculate the curve. In fact the bridge usually is a path across a flat land. Two points are taken from opposite ends of the bridge. Those points are surveyed to be the same height above sea level. When you observe curves in a bridge, its because we design the bridge to be sturdier by putting in an arch as can be seen in some suspension bridges. However the end points on the bridge remain at the same height above sea level.