As they said in school, show your work.
The 28L extended centerline crosses the bridge at approximately 37°34'21.00"N,122°15'49.20"W.
http://goo.gl/maps/sC6la
The 28L displaced threshold is at approximately 37º36'43.54"N,122º21'33.35"W.
http://goo.gl/maps/xJP48
The distance between those two points is approximately 31,227 feet.
Great Circle Mapper
The 28L PAPI has a 2.85º glide path and a TCH of 64 feet, so add 1,286 feet to get the touchdown point.
64/tan 2.85º - Wolfram|Alpha
So we have 32,513 feet between the bridge and the touchdown point.
31227+1286 - Wolfram|Alpha
That means to be on the PAPI at the bridge you would cross at 1,619 feet.
32513*tan 2.85º - Wolfram|Alpha