Yes - this is a picture on Curbed from almost a week ago that indicates foundation work has commenced over about half of the site. Also, the project sponsor is Equity Residential (NYSE: EQR). Doesn't get any more secure than that
All things considered, they made it after many years through SF's rigorous planning process, they hired an expensive architect (Glenn Rescalvo at Handel), demo'd multiple buildings, dug a hole deeper than you would find in nearly any other city, and now are paying close to $1,000/day for that crane.
http://sf.curbed.com/archives/2014/0...nanza.php#more
EQR broke ground on a separate $224M, 453 unit project elsewhere in SF at the same time, both projects of which were discussed on their 1Q14 earnings call. They are long on the market, which is considered the best or perhaps the 2nd best multifamily market in the country right now.