I personally think that BIM is a convergence of multiple technologies, and I am yet to be convinced that it will take off.
I presume you know what it is, but my understainding is that it is a fusion of architectural drawings, CAD, GIS and asset management systems. They talk about 5D models, i.e., 3 spatial, 1 temporal and 1 cost.
GIS has 2.5 dimensions, usually. But could have 3. (I.e., we could have points, lines and polygons that have 3D coordinates and that overlap each other.) BIM brings along the fine detail that CAD building plans have, and joins in with GIS attributes.
To answer your questions:
- How can GIS be leveraged to represent the physical and functional characteristics of a facility?
- it can represent the 3D physical characteristics of a building with 3D CAD/Architectural models. The functional is represented with pipes, wiring, equipment etc. being incorporated. (Think Sketchup, but with numbers.)
- How can GIS be used to control building project and data life-cycle information?
- By knowing what the building looks like now (in the form of a BIM model), and ensuring that all proposed and actual changes are supplied in BIM format, an up-to-date, and actually proposed or future, model of a building can be visualised and costed etc.
- How can a GIS-based approach to BIM offer better decision-making value?
- I guess that BIM must be GIS, in that the model should have proper schema and domains, so that attributes are handled in a standard manner between all people working on the project.
I'm not a BIM proponent, so I can't really comment on how it will/is/should be used, but, while it sounds like a great thing, getting people to actually use it (i.e., contractors, and even architects) is apparently a hard thing to do. A friend worked on making a bespoke model, then the architects wanted flat plans to work with! So information was destroyed, in practice!