Alternatives to welding square tube posts to 5/8 bearing plate

[fannanxx]

I have a structure that steel square tubing will be used as part of the framing. The plans call for bolting a 5/8 bearing plate into concrete and the square tube of 3/16 thicness will be welded to the bearing plate. I consider the bond between the 3/16 square tube edge and the bearing plate by way of weld not as strong as I want it. I wounder if there are alternative methods to connect the square tubes to the concrete foundation. Any ideas?

 

[hokie66]

It is not bond, it is a weld. Why are you concerned about the capacity of the weld? The base plate should be welded to the column in the fabrication shop, not in the field.

 

[desertfox]

Hi fannanxx

Might help if we knew why you consider welding not strong enough and what loads do you anticipate the square tube seeing.

desertfox

 

[paddingtongreen]

Hi fannanxx, you are not thinking of using one anchor bolt, hidden inside the tube, or are you?

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[fannanxx]

I am thinking of embedding square tube(1/2" skin thickness) deep enough in the concrete and rising one foot above the surface of the foundation. The side of this tube inside concrete will have two holes for a horizantal 5/8 rebar. The outside dimension of the embdded tube will match the inside dimension of the 3/16" square tube post. The square tube post will slide into the one foot stumb and will be bloted using 2 5/8 bolts. In case of seismic activity the square tube will engage the foundation laterally through a one foot of 1/2" inch tube rather than through the weld bead.

The reason I am not trusing a weld for a 3/16 to a flat bearing plate is my assumption that the system is as strong as its weakest point. This weld will give in to lateral forces in case of large seismic activities. Earthquakes are getting bigger and bigger and we have a large one expected to hit California (Hayward Fault) any time in the next 40 years.

 

[paddingtongreen]

I still don't understand, why would the weld be the weakest link? "Matching" weld metal has a higher yield point. A complete penetration weld will be stronger than the tube, and you could reinforce that with a fillet weld if you wanted to.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[beton1]

Besides what paddingtongreen states, you will now have 'two bolts' subject to shearing or the tube material tearing. Isn't a 'real anchor bolt' arrangement the way to approach this? Seems like reinventing the wheel. My .02$

 

[Teguci]

Stiffener plates at each corner? The box within a box is not KISS and is inadvisable.