Jiu-Kang Yu has an article "Bruhat-Tits Theory and Buildings" which has appeared in  "Ottawa Lectures on Admissible Representations of Reductive $p$-adic Groups". It doesn't directly address your question, instead it contains a guide to the literature on Bruhat-Tits buildings.

There is a <a href="http://citeseerx.ist.psu.edu/viewdoc/download?rep=rep1&type=pdf&doi=10.1.1.217.9089">26 page pdf</a> version of Yu's article. The published version contains a bit more information, but not a lot more (a few more references are added, plus a short introduction, plus the typesetting is updated). Unfortunately the printed version is  hard to find.