Large Equipment Seismic Requirements

[mcterry0624]

My company designs and manufactures large pieces of equipment (~10-30 tons) that sometimes are sold into seismic zones. I'm trying to write a procedure to document the expectations of all parties to be discussed at time of quotation. Since we don't design the buildings that these pieces of equipment are installed in, I'm thinking that we need to provide certification that the equipment has been designed to meet or exceed all applicable seismic requirements. I'm thinking right now I would provide:
1. A summary report detailing all the reaction forces for each floor support pad for operation conditions, including the overturning moments of each support frame.
2. A detailed sketch of suggested mounting details for each frame to the floor.
3. A certification letter stating that the equipment framing meets or exceeds all applicable seismic requirements.
4. All submitted drawings and calculations would be stamped by a licensed professional engineer.

Am I missing anything else?

 

[JAE]

Would it be correct that you are responsible for the equipment seismic stability "within itself" while the building's engineer of record would be responsible for the connection of your equipment to the building?

You state in No. 1 that you provide reaction forces at each floor support pad. Do you always have the ability to calculate these numbers? Some buildings have seismic isolators that would affect those numbers. Some buildings might be on different site classes that could affect the seismic demands. Other parameters may exist that you aren't aware of.

I'm just wondering if you should offer base reactions, but qualify them by stating how they were derived and that the engineer of record is ultimately responsible for verifying them and providing for the equipment-to-building connection?

 

[mcterry0624]

JAE - Thanks for the quick reply.

Yes, we are responsible for the seismic stability of the equipment itself. We basically ensure that it won't break apart during a seismic activity. The building engineer is responsible for the connection details, though we have given recommendations in the past. As for the reaction forces, they have been calculated in the past based solely on the acceleration and do not take into account isolators. The calculation package we give to the customer details out the method used, but this is something that I should add into my standard procedure.