Rethinking the SF Bay Bridge

http://www.insidebayarea.com/sanmateocountytimes/localnews/ci_13658982?source=rss
http://baybridgeinfo.org/faqs
http://www.dot.ca.gov/hq/esc/tollbridge/SFOBB/Sfobbfacts.html

After yet another near-lethal accident and emergency bridge closure for repairs that costs the region millions in economic productivity loss, maybe we should rethink the entire bridge concept anyway. We know the eastern span of the bridge is a piece of crap and won't withstand a 7.0 quake, which is why a new bridge is under construction.

The bridge's construction began in 1933 at a cost of $77M ($1.2B in 2009 dollars; a cool website to calculate: http://www.dollartimes.com/calculators/inflation.htm). Another $49M was spent in 1958 ($362M in 2009 dollars). In CA bill AB 1171 in 2001, $3.3B was allocated for bridge seismic retrofitting. $20B in new transportation bonds were issued in 2006 to address cost over-runs, which now total $6.2B and counting.

So instead of wasting ~$8B on building/maintaining the bridge, why not destroy it and dredge a land bridge instead? A Google search didn't find any proposals in circulation. You could have a small high-rise section for ships to pass underneath. We know the tourism snobs would say that a land bridge wouldn't be as picturesque, but we still have the Golden Gate don't we? Obviously a land bridge would be safer in a quake or storm (assuming the dredged Earth was stabilized properly and won't liquify from tremors). It will ease pressure on traffic, emergency responders, and Caltrans as well.

So the big question remains - would this idea be more or less economical? Under the bridge, nautical charts show an average water depth of ~55 feet. The bridge spans 3.68 miles of water. So assuming the land bridge would be 500 feet wide (very generous), that is 0.35 square miles. Well how much did a similar project cost? Dubai had Van Oord company (and the Dutch know their stuff when it comes to land reclaimation) build its famous "Palm Jumeirah" islands. They needed 90M cubic meters of sand and 7M tons of rock to dredge water that was 11 meters deep (28 feet). The archipelago extends 5 miles offshore and totals 700 hectares of land, which is 2.73 square miles - 8X the size of my proposed land bridge project. So it's a much larger project than the Bay Bridge span would need, albeit constructed with the help of dirt-cheap South Asian laborers. The whole Jumeirah cost $12B, but not sure what fraction was dredging. Maybe to get a sense, Van Oord won a new $4B contract to build an even bigger Palm (the Deira) in Dubai. This one is 4,000 hectares or 5.7X bigger than the Jumeirah, or 45X bigger than the land bridge. But since the Bay is 2X deeper than the Dubai coast, lets quadruple the cost to be fair. I am sure dredging jobs don't scale linearly, but just for argument's sake, that's a cost of only $360M. $6B just to retrofit the bridge vs. $0.36B to make a land bridge, hmmmm.

http://en.wikipedia.org/wiki/Palm_Jumeirah
http://www.sandandgravel.com/news/article.asp?v1=8727

But ~270,000 vehicles use the bridge every day, which at $4 per car is over $1M in revenues each day (and there are proposals to raise the toll to $5-6). So I guess it's a cash cow and a "pretty landmark" for the area, so we'll continue to sacrifice time, resources, and safety to maintain the bridge, when cheaper and safer alternatives exist.