Semirigid Endplate

[phdunn]

I am looking for any references to the proper connection curve for Endplates to use in semirigid connections. I have sloping roof girders that do not lend themselves to using flange angles that are described in "Semi-rigid Connections in Steel Frames" by the Council on Tall Buildings." If I had the proper formula for n in their power curve I would apprectiate it.

 

[14159]

Why not download AISC's free Design Guide 16 and use their procedure for designing a flush end plate?

I don't understand the "need" for a semirigid, or as we call them nowadays, a PR connection.

DBD

 

[phdunn]

DBDAVIS:
I have AISC design guide 16. Rigid connections result in expensive column stiffening or much larger columns. This is a two story warehouse with significant dead load due to a heavy floor for fork trucks. Limiting the connections to semirigid results in no stiffening. The lateral forces due to seismic were too large for top and bottom angles. The area is not high seismic that requires using the AISC seismic code. The local fabricators felt the end plates would be the most economical solution verses flange plates welded to columns per Omer Blodgetts "Welded Design of Structures."

 

[dbuzz]

phdunn

Can you use a fabricated angle, in lieu of a rolled section, to suit the slope of your beam and implement your preferred connection?

If not, I would have to second DBD's suggestion of a flush end plate, which is actually a semi-rigid connection. If you're concerned about excessive stiffening, note that in some cases it can be cheaper to use thicker end plates and heavier column and beam sections than to have heavily stiffened connections. Perhaps discuss with your fabricator.

A note of caution - semi-rigid connection design demands a knowledge of the true moment-rotation behaviour of the connection to enable a frame analysis to be carried out, and to allow the design of the connection itself.

 

[phdunn]

dbuzz
This is exactly my problem. The AISC has the properties for the strength of the connection. I can use the formulas from the Tall Building Council for stiffness. I don't have the connection curve for it! Any suggestions would be appreciated.

 

[JAE]

phdunn - what code are you designing under? Did you use R=3 for your seismic loads? Just wondering.

 

[phdunn]

JAE
yes
although AISC has tests indicating endplates can be used for higher R's per second edition of the end plate guide.

 

[miecz]

The constants for endplates are listed in "Stability Design of Semi-Rigid Frames" by Chen, Goto, and Liew.