ABS shrinks when it cools, which is probably why one side is lifting off the bed. The larger the object the more it will tend to do this.

I recommend hairspray on glass for ABS (specifically aquanet extra super hold). I'd also suggest printing at 140-145 for abs, if you print too cool your layer adhesion will suffer and the shrinking may cause layer separation.

Even with all that, you're still going to have problems with large ABS objects sticking unless you find a way to warm up your build chamber to something close to 50C.

Modifying your printer to actively heat the build chamber makes printing ABS a lot less frustrating, I modified my printer to vent a cheap low power hair dryer into the bottom of the chamber, the hair dryer is hooked up to a temperature controller that keeps the chamber exactly 50c.

Here's the mod: http://www.thingiverse.com/thing:1524781