Rigid base plate design

[sc]

G'day,

Just in need of a decent reference for the design of rigid base plates for hot rolled sections. All of the standard design guides avaoid the issue on cost basis, however I have to design one.

Do I simply do a standard design with additional bolting outside of the column area and apply a large factor of safety to the loads/moments that need to restrained or is there actually a straight forward method for design.

Any help or guidance is appreciated.



regards
sc

 

[Ron]

sc...The American Institute for Steel Construction (AISC) gives a straightforward method of baseplate design in the ASD Manual, 9th edition. The method given in the 9th edition has a bit more explanation than that of the older editions, but the process is similar.

 

[Taro]

Some additional references for base plates that also address applied moments:

1. Design of Welded Structures, Blodgett
2. AISC Design Guide 1, Column Base Plates
3. "Beam-Column Base plate Design", AISC Eng. Journal, Q1 1999

 

[dlew]

sc,

In rigid base plates the tension in the anchor bolts is large, and that requires thick base plates and heavy welding of the column to the base plate.

A type of base plate more appropiate for a rigid column base is shown on page 4-131 of the AISC's "Manual of Steel Construction", 9th edition. In this detail, the tensile force is transmitted to the anchor bolt through stiffener plates welded to the column, and the base plate itself is designed only for bearing.

Hope this will help

AEF

 

[UcfSE]

The references given by Taro are excellent, and provide an excellent methodology to base plate design. I would add one more to the list:

"Steel Structures: Design and Behavior" 2nd Edition, by Charles G. Salmon and John E. Johnson. Newer editions of this book refer to the 2nd edition and to Blodgett, so you will need to find it used ( I found mine through Amazon) or perhaps a senior colleague will have a copy. This is what i use for base plate design.

 

[MarkRPflow]

See AISC "Steel Design Guide Series" Book #1 - Column Base Plates.

http://www.aisc.org

 

[chichuck]

sc,

I have a Mathcad 2000 template that does the calculations for the method described in Omer Blodgett's book. If you'd like a copy, email me at thheup@hotmail.com .


Regards,

chichuck

 

[dbuzz]

G'day SC,

The Autralian Steel Institute (

http://www.steel.org.au)

is a great technical resource for steel design and construction issues.

I suggest you make contact the ASI Manager for your home state:
- Queensland and NT
John Gardner
johng@steel.org.au
Tel (07) 3853 5320
Mob: 0418 788 870
- WA and SA
Rupert Grayston
rupertg@steel.org.au
Tel (08) 9480 1166
Mob: 0419 922 294
- NSW and ACT
Scott Munter
scottm@steel.org.au
Tel (02) 9929 6307
Mob 0418 970 899
- Victoria and Tasmania
Leigh Wilson
leighw@steel.org.au
Tel (03) 9556 5422
Mob 0417 353 364

 

[sc]

Thanks DBUZZ,

I've already been in contact with them and had a reasonably poor response along the lines of are you a member? if not join and we will be able to provide better assistance via our library otherwise purchase a book from our list.

So I had a look at the list available and determined that what was offered was along the lines of pinned bases with very little guidance offered on rigid base design. I refuse to join just to access their library (which by all reports is excellent) once or twice a year.


I have since carried out the design in accordance with AS4100 and placed all bolts outside of the flanges, along with a "thick" base plate and "thick" gussets. The design is based on reducing deflection/distortion of the base plate to an absolute minimum, increasing the hold down ability of the bolts (by a FS of 3) and ensuring that the member supported does not change excentricity of load until the minimum required fire protection period. This was done to ensure that the loading situation doesn't change on the base connection too early.

I have run the design by a college, who is satisfied that it is sufficiently rigid for the intended purpose.

Regards
sc

 

[dik]

You may want to download the document at:

http://www.steel.org.au/members/pdfdocs/sc_v36n2_web.pdf

 

[sc]

Thanks Dik, I already have and understand the design method for pinned bases.


sc