Why was the steel and concrete used in Golden Gate Bridge?

- Strength and durability: Steel is a strong and durable material that can withstand the weight of the bridge and the forces of wind and earthquakes.

- Malleability: Steel can be easily shaped and formed into the various components of the bridge, such as the cables, suspension towers, and deck.

-Resistance to corrosion: Steel is resistant to corrosion, which is important in a marine environment like the San Francisco Bay.

Concrete:

- Strength and durability: Concrete is a strong and durable material that can withstand the weight of the bridge and the forces of wind and earthquakes.

- Fire resistance: Concrete is fire-resistant, which is important in case of a fire on the bridge.

- Cost-effectiveness: Concrete is a relatively inexpensive material, making it a cost-effective option for a large-scale project like the Golden Gate Bridge.

In addition to these reasons, the use of steel and concrete in the Golden Gate Bridge was also influenced by the engineering practices and materials available at the time the bridge was built (1933-1937).