Seismic Design - Crane Support Structures

[WBell]

Crane support structures are not specifically mentioned in the IBC Code (ASCE 7 by reference) for seismic design of building structures or non-building structures. The State of Illinois Engineering Code of Conduct lists the type of structures requiring an SE seal, which would appear to include crane support structures. Assuming the crane support is to be designed for seismic loads, the structure type needs to be determined, i.e., building vs. non-building. If anyone has experience in the seismic design of crane support structures, please comment on what requirements were used for the analysis - building vs. non-building.

For information, the crane support system in question uses cantilevered columns supporting the crane runway beams, with headers and stringers connection the columns at the top.

 

[HTURKAK]

I understand ( pls correct me otherwise) , the subject is , seismic design of crane supporting structures (i.e. overhead crane at an industrial bldg ...)

I preferred to copy and paste related items from the codes;

ASCE 7-16 C12.7.2 Effective Seismic Weight. During an earthquake, the structure accelerates laterally, and these accelerations of the structural mass produce inertial forces. These inertial forces, accumulated over the height of the structure, produce the
seismic base shear. When a building vibrates during an earthquake, only that portion of the mass or weight that is physically tied to the structure needs to be considered as effective. Hence, live loads (e.g., loose furniture, loose equipment, and human occupants) need not be included.....

AISC DESIGN GUIDE 7 13.6 Seismic Loads Although cranes do not induce seismic loads to a structure, the crane weight should be considered in seismic load determination. The seismic mass of cranes and trolleys that lift a suspended load need include only the empty weight of the equipment. The designer should carefully evaluate the location of the cranes within the building in the seismic
analysis.
Where appropriate, a site investigation should be performed in order to determine the soil profile type for seismic
response. Seismic response interaction between the crane building and equipment should be taken into account.....

That is, the crane ( except own wt ) does not induce seismic load to the supporting structure. The lifted load is not tied to the structure and does not vibrate together ..

I have experience with SNIPS.. which assumes for vertical seismic effect ..

 

[WBell]

AISE Tech. Report No. 13, 2003, "Guide for the Design and Construction of Mill Buildings", references ASCE 7 for seismic design requirements. ASCE 7-10 (I'll have to update) Chapter 15, Table 15.4-2, Type: Inverted Pendulum, appears to be the appropriate structure type. The crane support structure, if it is free-standing, is designed to transfer lateral forces, including seismic, to the foundation elements. The crane system mass is supported at the top of the support system, which would indicate that the appropriate Structure Type is an Inverted Pendulum.

Thank you for your comments/recommendations.