The Total operating weight of permanent equipment
The Total operating weight of permanent equipment
(OP)
Guys, As per ASCE_7-05, clause 12.7.2 "Effective Seismic Weight", The Total operating weight of permanent equipment should be considered in the earthquake analysis. My question is, in case those permanent equipment have both static weight and continues dynamic loads, should i consider those dynamic loads as part of the "Total operating weight" or neglect the dynamic and consider only the static weight of the equipment?.





RE: The Total operating weight of permanent equipment
RE: The Total operating weight of permanent equipment
In fact i am thinking the same.. However, i want to be 100% sure that the interaction between the building response to a dynamic force of equipment and the building response to ground motion is negligible. i would appreciate if you can refer me to a book or code that discuss this matter.
RE: The Total operating weight of permanent equipment
If the equipment requires liquid to operate, the weight of that liquid should be included in the operating weight.
The reason that dynamic loads from equipment are not included is due to a couple of things.
Low probability. This can be seen in various load combinations. The odds of the design seismic event occurring simultaneously with maximum equipment dynamic loads is probably extremely low. (You could make a case for a certain percentage of the dynamic load in addition to seismic load.)
The other reason is that considering dynamic loads could actually reduce the effects that seismic motion has on the structure. Depending on the nature of the dynamic loads, they may add damping or affect the period of the structure.
RE: The Total operating weight of permanent equipment
Thaidavid
RE: The Total operating weight of permanent equipment
Does it matter if this happens only once a year? once a month? once a week? or several times a day? At some point we had to acknowledge that this is a normal operation load. If so, then the whole contents must be considered.
Personally, I would like to find a reference which can define the difference between such an upset case and an operating load.