From article, (Due to huge upkeep costs, some people have suggested reconstructing the Golden Gate Bridge in a way that would limit ongoing maintenance and operation bills. Setting aside the political feasibility, how would engineers design the bridge if they were going to build it from scratch today?
Over time, researchers have developed lighter materials. Using Fiber Reinforced Polymers (FRPs) rather than steel or concrete is a way to reduce the weight of a structure of this magnitude. This self-weight is typically responsible for using up 70 to 80 percent of its resistence – that's the maximum load it can bear before it fails. By reducing it, the bridge's structure would need less strength, allowing for cheaper and easier options.
For example, designers have started using Fiber Reinforced Composite (FRP) materials in bridges such as the Market Street Bridge in West Virginia. FRP uses a plastic resin to bind together glass or carbon fibers, which give strength to the material. Being four times lighter than concrete, the FRPs are five to six times stronger.
Probably a designer's first target for change in a substitute Golden Gate Bridge would be the composition of the cables. The steel currently in use is corrosive, heavier by four times than newer materials and can fail in harsh moisture and temperature environments – just like those it encounters in this location. Carbon cables are more inert and already in use around the world.
These lighter-than-steel materials could also be utilized in other elements of the bridge, such as the traffic roadway. Using plastic composite decking could bring the Golden Gate Bridge's deck self-weight down by a factor of five. That would enable engineers to design and construct a cable-stayed bridge rather than a suspension bridge. The advantage there would be the ability to do away with the suspenders; in a cable-stayed bridge forces are transmitted directly from the deck to the towers by the cables. The first highway cable-stayed bridge with CFRP cables is Switzerland's Stork Bridge, opened in 1996.
A cable-stayed bridge can have a longer span than a suspension bridge, so its structure between the supports and the shore could be simpler. Also building the towers nearer to the shore, where the waterbed is more shallow, would help alleviate one of the main problems when the Golden Gate Bridge was constructed the first time around: It's very difficult and expensive to work on the tower foundations in deep water with strong currents.
The damping system could also be addressed with a new design. The lead core-based dampers that were used in the construction of the Golden Gate could be replaced by newer technologies that are better able to resist wind, traffic and seismic forces. This improvement would ensure that a failure such as the one on the Tacoma Narrows Bridge – when wind blew the bridge sideways, it twisted and collapsed – would be prevented.
With all that said, the Golden Gate Bridge is still doing fine.)
Me, "People question the idea of which kind of bridge is better? A Suspension Bridge or a Cable Stayed Bridge. A lot of this has to do with the culture that engineers are brought up in. At the time of construction of the Golden Gate Bridge, in the 1930's, and even as late as the Verrazano bridge, in the 1960's, there were a lot of engineers favoring Suspension bridges as the preferred method of spanning huge distances. But the present day culture is in favor of Cable Stayed Bridges that can span longer distances, so they are the preferred cheaper option. One just needs to look at the three bridges being built around NYC: the Goethals Bridge, Kosciuszko Bridge, and the New Tappan Zee Bridge. All are cable stayed bridges. So the engineers must have picked them for some reason."
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