steel plate deflection 1/2 inch

Hello all I am new to the forum and am in need of some information. I have a hole I want to cover but will need access to in the future as it leads to an outside crawlspace window. After reading some information on your forums I can say that I was thinking of using a piece of 1/2 inch steel that will be supported (not secured) on three sides. The dimensions are 61 9/16" x 28 9/16". Only one of the longer sides will be supported. The support comes from a 2' lip of concrete on the other sides (I can make this 3"). The reason for the steel is because I want to place some cedar planks over it and two sitting chairs. Figure it needs to support 500lbs max and not deflect much more than 1/2" for safety. I believe the cedar at one inch thick going over it will add additional strength as well. What are your thoughts because I am feeling overwhelmed and the steel yard wants 600$ for the plate with 20 holes drilled in it for water to get through. Thank you in advance, Charles

Hi Charles, 1/2" steel would be overkill for what you need and as you have found out, very costly.

If you give us a sketch or some pictures of what you are trying to do, then we may be able to offer some more useful suggestions. I assume you were thinking steel as there is an issue with height.

Personally I would be looking at a lumber issue, but without any idea of what we are working with, it is impossible to say at this point.

Might want to look at welded grating? Or stiffen a thinner plate with a piece of channel underneath?

Thank you for getting back to me so quickly. I will take a photo and make up a sketch later and attach it. Thanks Thanks Thanks

Maybe a minimum of 1/8" and a max of 1/4".

[QUOTE=ME_student;6727]Maybe a minimum of 1/8" and a max of 1/4".[/QUOTE]

Based on your stated current position in another post here, within the Engineering world that is a very risky statement to make when you know nothing of the actual situation.

The OP could foolishly take your advice and spend $300 on plate steel to find it that it did not come close to supporting the load required. If you are going to offer advice and suggestions, PLEASE make them based on Engineering FACTS! That's why we requested clarification with a photo or sketch.