TIMBER POST BASE MOMENT CONNECTION 3

[lextoo]

WHERE CAN I FIND EXAMPLES REGARDING DESIGN PROCEDURES FOR
DETERMINING FIXED BASE CONNECTIONS FOR TIMBER POSTS TO CONCRETE FOOTINGS.

ANCHOR BOLT SIZE AND SPACING, BASE PLATE
THICKNESS, BASE DETAIL CONFIGURATION, ETC...

THANK YOU...

 

[RockEngineer]

It is hard to get a fixed connection at the base of a wood column in concrete without burying the column several feet in the dirt and concrete and using the lateral soil bearing equations for poles of 97UBC 1806.8 or 2003IBC 1805.7 . When you bury the post in the concrete you can have problems with rotting at the surface line. One way that I accomplished a fixed end post in a log column was we buried 12" I beams vertical in the concrete. Then we did a kerf cut in the bottom of the log column about 24" deep the shape of the I beam. We drilled holes in the I beam and mating holes through the log column and bolted through the log column to the I beam. This kept the wood away from the moisture and provided a way to get a fixed moment at the base. You don't even see the I-beam just a line of bolts up the bottom couple feet of the column. We had to check all the shears and moments to make sure we didn't overstress the wood, bolts or I beam.

Sometimes it takes a little imagination and ingenuity but it can be done.

 

[lextoo]

OK...ROCK ENGINEER--THIS IS GOOD AND I LIKE IT...
--BUT, FOR THE PARTICULAR SITUATION THAT I HAVE THE CLIENT IS LOOKING
TO SEE A STEEL BASE "SHOE" WITH ANCHOR BOLTS, ETC...WHERE ARE THERE EXAMPLES OF THIS METHOD OR SIMILAR METHODS...
(WHAT I HAVE IS AN APPROX. 4 FT X 8 FT SIGN ABOUT 17 FT HIGH)

THANKS...

 

[RockEngineer]

How about a thick steel baseplate with the bolts well spread out to get the moment connection and a square tube welded to it. The tube would have inside dimensions equal to your wood post size and the post fits in the square tube. You would have to work out all the sizes and bolt placements based on your loads. You have to have a base that is strong enough and wide enough to give you the moment connection. This is not easy. You would need drain holes at the bottom of the tube because you will never be able to keep the top sealed out in the weather.
Good Luck
[reading}

 

[lextoo]

DO YOU KNOW OF ANY LITERATURE THAT ILLUSTRATES THIS APPROACH?


THANKS AGAIN

 

[RockEngineer]

That was just in my head. I am under the gun on projects right now so I don't have time to help research. When I get a minute I will see what I can find.

Anyone else out there have some ideas for lextoo?

 

[Beggar]

lextoo: Please turn off your CAPS LOCK. It's hard to read all-caps writing and many people interpret it as "yelling."

 

[lextoo]

thanks for the suggestion...

 

[mkberry]

I recently had to do this for an octagon shaped gazebo. Here is a simplified description: I used a base plate with anchor bolts into the concrete foundation sized and spaced to resist the applied moment. Welded to the base plate were two 5"x24" vertical plates. My 6x6 post fit in between these verts and two groups of thru-bolts at the top and bottom of these plates transferred the moment from the post into the base plate.

 

[lextoo]

thanks, mkberry

 

[ozman2004]

lextoo
check out deck designs there must be a moment connection there for you.