The Verrazano-Narrows Bridge and The Curvature of The Earth

Accounting for the curvature of the Earth is not usually needed for narrow high-rise building projects. Designers only need to ensure the foundation is flat, and the curvature of the Earth becomes non-factor.

For projects that extend over a long distance, like roads, railroads, canals, etc, they are built along the curvature of the Earth, and specifically accounting for the curvature is usually not needed.

But when the project extends on a long a distance, as well as extending upwards, then we have no choice but to take the curvature of the Earth into account. One of such projects is the Verrazano-Narrows Bridge, New York, United States.

The towers of the bridge are 1 inches (41.275 mm) farther between the tops than at the base. The curvature of the Earth needs to be taken into account because the project extends on a relatively long distance as well as upwards. The height of the towers are 693 ft (211 m) and they are 4,260 ft (1,298 m) apart.

If the curvature of the Earth is not taken into account, then the two poles would not be straight towards to the center of Earth’s gravity, and the bridge will not be able to support itself properly. The cables would have to support some of the weight of the towers, as well as the load from the passing vehicles.