I have posted a couple of threads regarding this subject in the past, but I would like to post a more thourough question regarding providing seismic design on steel stairs. I have a particular project which is in the Missouri area and is governed by the 2006 IBC and ASCE 7-05. I have about 6 steel stairs that I have to provide seismic design for.
For information purposes, say I have a typical stair that starts at the finish floor goes up to a intermediate landing approximately 7' above finished floor and then the stair proceeds to go up another 7' to 2nd floor above. Based on this information, I could say that the stair is definately not part of seismic resisting system in the building but an independent structure that must transmit the seismic force into the main seismic resisting system.
Would you design the stairs using the Chapter 12 of the ASCE 7-05 (Seismic Requirements for Building Structures), Chapter 15 of the ASCE 7-05 (Seismic Requirements for NonBuilding Structures), or Chapter 13 of the ASCE 7-05 (Seismic Requirements for NonStructural Components)?
After a specific design procedure is chosen, what is the correct way to apply the seismic load? Would you apply the seismic force individually to each stair stringer and landing? Or would you apply a seismic force to the whole stair structure at the center of gravity of the whole stair structure which would probably be at the intermediate landing?
I have tried to be as specific as possible. It just appears that the codes do not address the issue of seismic effects on steel stairs, but architects and engineers are requiring that stairs be designed for seismic effects. Any help on this issue would be greatly appreciated.
Val
For information purposes, say I have a typical stair that starts at the finish floor goes up to a intermediate landing approximately 7' above finished floor and then the stair proceeds to go up another 7' to 2nd floor above. Based on this information, I could say that the stair is definately not part of seismic resisting system in the building but an independent structure that must transmit the seismic force into the main seismic resisting system.
Would you design the stairs using the Chapter 12 of the ASCE 7-05 (Seismic Requirements for Building Structures), Chapter 15 of the ASCE 7-05 (Seismic Requirements for NonBuilding Structures), or Chapter 13 of the ASCE 7-05 (Seismic Requirements for NonStructural Components)?
After a specific design procedure is chosen, what is the correct way to apply the seismic load? Would you apply the seismic force individually to each stair stringer and landing? Or would you apply a seismic force to the whole stair structure at the center of gravity of the whole stair structure which would probably be at the intermediate landing?
I have tried to be as specific as possible. It just appears that the codes do not address the issue of seismic effects on steel stairs, but architects and engineers are requiring that stairs be designed for seismic effects. Any help on this issue would be greatly appreciated.
Val
