A single envelope is inherently dangerous. One single pop and everyone is sky diving - minus the parachute.
Even the great airships of yester year worked around this by not having a single compartment filled with hydrogen/helium, but by having many smaller bladders organised for easy maintenance and attached to the airframe. The outer skin was for aero dynamics.
To that end my advice would be to construct many smaller vacuum vesicles. These will of course present a less efficient buoyancy as there will be a higher material to space ratio. On the plus side though you can construct these in the must efficient shape - a sphere - and forego internal reinforcement structures as the surface thickness is sufficient to offset any implosive tendencies.
This general concept can handle some fairly extreme pressure differentials, just take a look at the research and engineering on deep sea submersibles. The Marianas trench, the deepest part of the ocean with the highest most crushing pressure, was traversed by a submersible with humans inside. While not strictly a vacuum on the inside (insert pun of your choice) the difference in pressure between the inside and outside of that vessel was extreme.
As for materials, I am unsure what would be suitable. Glass definitely has the capability to maintain high quality vacuums at sea level. However I'm pretty sure that it is far too heavy to be usable for an airship. Otherwise we would have some very interesting science toys.
Metals could indeed fill the gap, but they too have issues. Corrosion is one, but i believe they are still limited here in that the thickness required places it as too heavy.
I suspect you would be most interested in space age fabrics such as those used in the Bigalow space hotels. Perhaps these with a minimal (perhaps spherical) bar frame. The fabric could obviously be refined more, as certain properties needed for space are useless in atmosphere. But there is a start.
Either way there are better ways than internal struts to distribute compression forces.