Stairway into Underground Vault

[CaliDave]

I'm trying to design a new stairway to an existing underground pressure reducing vault. I was wondering if any of you all know of any pre-cast type of stairways similar to a cellar entry such as this that could be used in a H-20 area:

http://www.sheaconcrete.com/bulk_stairs.aspx

The main thing keeping me from using this type of product is that they are not designed to have a flat doors on top that can withstand H-20 loading.

I could have our structural team design something that would work but I want to explore the Pre-Cast alternative.

Thanks

 

[coloeng]

Why not fab some stairs with steel. This could be pre-fabbed off-site and then installed in the vault.

 

[JedClampett]

Their design has a sloped hatch that wouldn't work for roadway use. I'm assuming it's sloped so you could access the latch from inside without rapping your head.
If you could figure out a way to unlatch the hatch,Bilco makes H20 hatches.

http://www.bilco.com/home.asp?country=93

As a caution, even their H20 rated hatches can't take anything more than occasional traffic.