Phase IV Expansion and Remodel Project at John Muir Medical Center – Walnut Creek Campus. The 400,000 square-foot expansion added a new, five-story tower, underground loading dock and a Central Utility Plant to the medical center’s Walnut Creek campus. The new tower is a steel-braced frame with concrete slab over metal deck. The main lobby features a cast in place concrete water feature rotunda. The hospital also features several gardens with architectural concrete at various roof levels.