Slightly hyper modern/futuristic (dystopian) city project - WIP!

I need to extend my portfolio and because I love architecture I decided to do some architectural projects (The Architecture academy might have inspired me some too).

I have some previous arch projects that I will finish, but I’m going to do some new projects too and since I really like architecture with a “clean concrete look”, that what I decided to start with.

Andrew Price says: “You always need to have a story in your images”.
Philip Bloom says: “Screw stories, do what you think looks good!”.
I say: You don’t need to portray a story, but it can help in the creative process as you get reasons to why you should include certain objects and not others etc etc.

So what’s the story for this project? Well, it started without a story and it was just a sort of corridor with rooms on the sides (rooms/windows to come). Then it evolved a bit and the “oasis” in the middle was added.
That developed into an idea of a “futuristic” city with a circular design (slightly inspired by the city in Aeon Flux).
The city is supposed to be something like “The Capitol” in the Hunger Games, where the ruling class, the elite, lives. A pristine place without any traces of the despair outside the city walls.

I’m going to add more features, like windows, stairs etc. I will probably use a lot cleaner texture on the walls.

Right now I’m working with Cycles, but I might render it with Octane in the future.
But I have a problem: the grass (and somewhat the trees) eats up quite a lot of memory and it brings it right up to the memory capacity of my GFX-card (sometimes… it’s acting a bit weird).
There are also some other problems with the grass since particles wont export to Octane.
I also use a particle system for the tiles, I used it together with a special material setup to get randomness to the looks of the tiles.

Latest render:

Earliest render:

Current plan over this part of the city: