huangyhg

bridge crane seismic loads on buildings
i am analyzing existing industrial buildings for seismic upgrades in zone 3. these buildings have cranes. my question is what % deadload should be used for analysis and what is the reference. i checked asce 7, asie technical report 13 for construction of mill buildings, aisc design guide 7 part 2 for design of industrial buildings with cranes, aisc seismic provisions and 97 ubc. all these address cranes but don't seem to provide the information i need for a "simplified seismic analysis".
pre 1990 documents i have looked at use a constant accelleration factor of 0.45g in major horizontal planes and treat the cranes like machinery attached to the building with a higher acceleration due to the possibility of a different frequency than the building. i don't find this method after the seismic codes changed in 1994.
does anyone have some united states code references on the current method of analyzing buildings with cranes?
check out our whitepaper library.
in the ibc 2000, section 1617.4.1, the definition of w (for the mass of the building) includes in the amount for w the following:
"3. total operating weight of permanent equipment."
this would be the weight of the crane, rails, and hoist dead loads. no mention of crane live loads is included as i would imagine the natural period of the hung weight would be so large as to negate any resonance with the building period.
i would only use the permanent weight and not the hoisted load for the seismic analysis.
the hoisted load is not fixed to the structure and will not contribute to the exciting force

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