Wood moment connection? 3

[rsagret]

Can a moment connection be made between a steel post and an LVL, flitch beam or any other wood member to be used as the main lateral resisting system of a one story residential building? There is no room for shear walls and steel frame is not an option. Anyone able to give me some direction on the this....Thanks

 

[DaveAtkins]

I would start by trying a steel cap plate on the post, with lag screws into the bottom of the beam. Moment at the connection will cause withdrawal in one of the lag screws. If that doesn't work, perhaps a steel saddle on top of the post will work. With this option, the lag screws are in shear.

DaveAtkins

 

[rsagret]

I am somewhat concerned about the connection loosing over time as well as the actual moment capacity that can be achieved with the connection. I was told that is not really good practice to use wood in a moment connection, do you think differently?

 

[RARWOOD]

Generally moment connections are avoided in wood design for the reasons you list, in addition to other factors. The main problem is the amount of slippage that occurs in the joint before the fasteners take up their load.

There are some cases where moment connections are required. The most common example is large radial arches, where the arches are spliced so that they can be shipped in smaller sections. It is my understanding that the Chicago Bears Training Facility has glulam radial arches with moment splices.

The use of a LVL or glulam with the column is a possible solution, depending on the magnitude of the moment that needs to be developed. You should consult the current AITC Timber Construction Manaula along with previous editions.

 

[phdunn]

Simpson Stong Tie has devices intended to overcome the shrinkage problem. Essentially every shear wall is moment connected at it's base, so wood connections are used all the time for wind and seismic loads. I would not depend on loading a moment connection for dead loads due to creep and shrinkage.
Also, wood shrinks least along it's length, so I would add steel straps to the top and bottom of the LVL which would be welded to the steel post