In the US, there are legal requirements for who banks can lend money to and how much they can lend to those borrowers. A bank will lend exactly the amount of money for which they can find qualified borrowers. Its a market equation that has nothing whatsoever to do with the required reserve.
Before someone points it out. Yes, those legal requirements are often poorly formed, laxly enforced and if they worked properly, the banks wouldnt have needed to get bailed out. I dont think the system is perfect, or even good. I just think its not as described in this post.