Crane Supporting Steel Structures

[WBell]

I am currently developing an analysis model for a 5T top running single girder, pendant operated crane in an existing structure. The owner has decided to support the 3-bay free standing structure on drilled shafts to allow the structure to be located up against the wall. For developing loads and load combinations I have the following references:

1. AISC, Steel Design Guide #7, Industrial Buildings - Roofs to Anchor Rods, 2nd Edition
2. CISC, Guide for the Design of Crane-Supporting Steel Structures, 2nd Edition

Both have detailed discussions of load cases and combinations and the AISC Guide makes frequent reference to AISE Technical Report 13, which I have not been able to locate. If anyone knows of where this document can be found, I would appreciate the information.

I found the discussion on page 52 (Ref. 1) to be very helpful in reducing the conservatism when considering the case for multiple cranes, which I am designing for. The AISC Guide doesn't really recommend strength (LRFD) vs. allowable stress (ASD) design method, whereas the CISC is based on LRFD.

I would like to share the design criteria that is developed for this crane support structure and if there is anyone out there who has already thought this through, I would appreciate your comments.

Wayne Bell, PE
BELL Engineering

 

[dik]

go ahead... someone is likely able to answer your querys.

Dik

 

[amec2004]

Check this out

http://asp.civilbay.com/crane.aspx

It can design up to 2 cranes running in the same aisle at the same time

AISC Steel Connection Design Software

http://asp.civilbay.com/connect

 

[WBell]

Thank you for the response. I am using RISA-3D for the analysis and it has a moving loads analysis tool, which I am using for the load combinations referenced in the ASCE Guide. There seems to be a lot of room for "engineering judgement" as to which load combinations are applicable. I have two (2) cranes operating in three (3) bays that are 25' long x 42' wide. I will submit a load criteria sheet based on what I think are the required load combinations.

As I understand, the only code requirement for this project (Corsicana, TX) is IBC 2015, which references ASCE 7-10; therefore, in addition to the load combinations given in the reference documents, I will make sure to envelope the Section 4.9 Crane Loads listed below.

AISC Section 4.9 CRANE LOADS

4.9.1 Crane Live Load 10,000 lbs Rated capacity of crane.
4.9.2 Max. Wheel Load 16,388 lbs Weight of bridge, rated capacity, and weight of trolley.
4.9.3 Vertical Impact Force 3,278 lbs Increased wheel loads to determine the induced vertical impact.
4.9.4 Lateral Force 2,258 lbs 20% of the rated capacity plus the weight of the hoist and trolley.
4.9.5 Longitudinal Force 1,639 lbs 10% of the maximum wheel loads.

I worked on the design basis documents for a nuclear plant (US EPR 1600) and prepared the load combinations for the nuclear island, so this shouldn't be too difficult, just need to pay attention to the details.

 

[amec2004]

10 kips capacity = 5 ton, it's almost like a monorail, don't worry that much

For a 5 ton crane, you don't need pay that much attention. I have PE down the US purchased my program doing 100 Ton crane, or stacker crane which has 200% of lift load as side thrust (normal crane is just 20%).

In those cases you need my program.

AISC Steel Connection Design Software

http://asp.civilbay.com/connect

 

[FLCraneBuilder]

1. Get actual weights & loads from a crane builder or the crane builder you will be using.
Attempting to circumnavigate those guides without real information is likely a waste of time.
The loads you mentioned seem extraordinarily large for a 5 ton crane. You did not mentioned the span of the crane or application, so its hard to grasp where those #'s came from.
2. Many crane builders will also quote you the runway system. If they do so, they can then also provide you column loads that include the weight of runway beam and rails.
3. With that information, your design scope may be narrowed down to foundation design.
4. You mentioned a "free standing structure". I assume this means you do not want to use the building to resist the (possibly small) horizontal forces. This puts you in to moment columns or a-frame columns - both of which add a bit of complexity to the foundation design.
5. ASIC has a crane runway beam design spreadsheet (free download)... plug in real weights & loads, select a bay span. Chose a beam.. easy peasy... This tool will assist you in narrowing down the "model" you initially spoke of. It can also be used to verify a crane builders work (if you go that route)
6. Ref tying the crane system back to the building to resist horizontal forces; smaller cranes of this nature almost always have horizontal forces that are much less than wind load... so tying back to building should be acceptable.. This is also a big cost issue.. Moment cols & moment resisting foundations are pricey

 

[dik]

Make sure you stipulate the loading conditions in your drawing notes.

Dik