Welcome to DPC. You have two Challenges under your belt now and it looks as if you are enjoying the site.
You asked for a Critique on your nice photo, so here I am. The image met the Challenge nicely with the great pattern - I'm guessing in a ceiling. I really like the colors and the composition. Both work well.
As some of your commentors pointed out, your image could use better focus and parts of it are "blown out" or very 'hot'. Unless you were taking this in near pitchblack conditions, I think your ISO of 800 is a touch high and with a shutter speed of a second and a half, unless you used a tripod, you really had no chance of a good sharp image.
This is the type of shot that cries out for bracketing. If it was mine, I'd try under exposing and over(well maybe not on this one) exposing, changing ISO numbers, changing aperture openings.
You've got a great camera that can do a lot for you. And you've got a good eye. I look forward to seeing more of your work on DPC.
This is a great pattern though I think I would prefer it sharper. The centre is a little over exposed too. I think if these were better you would have nailed it with this shot.
Interesting subject and lines here. The lighting in the middle looks quite blown out to me, and the focus isn't very sharp. I'd love to see this exact same shot in sharp focus and exposed without any blown out highlights.