Live load-auditorium with fixed seating

[WWTEng]

This is a first floor auditorium, existing, with a basement below. Built in the 1920s. They want to resurface the floor which would add a net additional 2" of concrete (extra dead load). If I used 60 psf for the fixed seating area per ASCE 7-05, I can prove that the existing structure is adequate.

But is 60 psf the correct load, or should it be 100 psf for public area.

Thanks.

 

[JAE]

With fixed seating, that reduces the ability of crowds to congregate and therefore avoids a higher (100 psf) load.

If the seating is ever removed in the future, there could be problems with assembly loading. I'd be tempted to use the 60 psf and then post the live load at all the doors.

There should also be a fire marshall maximum capacity listed (based on area and exits) and that could be used to help you determine the theoretical maximum load on the floor.

 

[slickdeals]

What is the floor framing? Is negative moment controlling or positive? If positive, can you use 2" of concrete in your compression area and push the N.A. up?

 

[MiketheEngineer]

IBC says 60 psf - Look it up

 

[msquared48]

Design it for 100. Post it for 60.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com