Tag Archives: sturdi-wall brackets

The Case of the Frost Heave and a Pole Barn Porch

Allow me to preface this post about a frost heaved porch with a reference to Sherlock Holmes.

Sir Arthur Conan Doyle’s Holmes and Watson solved fictional criminal dilemmas with deductive reasoning. In my cases, nearly 40 years of experience (plus knowing and relying upon input from many brilliant engineers) allows me to recommend solutions with a fair degree of certainty as to their outcome.

Reader RICHARD in WOOD STOCK brought to me this interesting case:

“My concerns pertain to my 50 foot by 72 foot pole barn which was built in 2008.
The barn has a brick paved porch that wraps around the length of the barn on the south side of the building. The interior of the barn has a cement floor, poured at the time of construction.

The barn has been very stable and sturdy since it was built, that is until this winter.
Shortly after the subzero weather we had in northern Illinois back in January, I was checking the barn for any issues and noticed that the pavers at the end of the porch had heaved up and the soffit of the porch was no longer level. Upon closer inspection I found that the two last support poles for the porch appeared to have heaved up causing the porch to lift and pull away from the barn to the point of wrinkling the steel siding. I have been closely monitoring the situation and have noted that the porch continues ton move up and farther away from the barn. M

Mike the Pole Barn Guru responds:

I’d say Richard is probaby correct as to heaving cause. His building might get some degree of return to normalcy after Spring thaw, however probably not back to straight and level.

Without involving services of a geotechnical engineer, who could actually do an onsite evaluation – about best I can offer will be how I would probably attack this challenge. I’d temporarily support the porch in the heaved column area. Cut both of these columns off at grade. Excavate ground below columns to remove embedded portions. Excavation needs to be deep enough so bottom of hole will be 1.5 times frost line depth below grade (probably around six feet). Place an appropriately sized Bigfoot® (https://bigfootsystems.com) in excavation bottom with a Sonotube® (https://www. sonotube.com) above. Use Sturdi-wall Plus wet set brackets (https://www.hansenpolebuildings.com/2017/05/sturdiwall-brackets/) in top of concrete poured in Sonotubes® to attach remaining portion of columns. All of these above suggestions, as well as proper sizing of Bigfoot and diameter of Sonotubes®, should be confirmed by a Registered Design Professional (RDP – architect or engineer), ideally whomever designed your building originally. Moving ground water away from your building will also prove to be an excellent idea to reduce or eliminate future challenges from frost heaves.

 

For extended reading about Bigfoot® Systems and Sonotubes® please see https://www.hansenpolebuildings.com/2018/05/bigfoot-systems/  and https://www.hansenpolebuildings.com/2013/11/sonotube/

Dry-Set Column Anchors

I’ve always been a fan of the traditional pole building foundation process. Face it – it is fairly low tech. Most folks have the ability to dig or auger a hole in the ground, stand a pressure preservative treated column in the hole and pour ready-mix concrete under and around the base of the column to resist the applied forces.

However not everyone has this luxury – in some cases, an adequate concrete slab or foundation wall is pre-existing.

Along comes the post-frame solution, brackets such as the Perma Column drill set Sturdi-Wall (https://www.permacolumn.com/drill-set-models) or AJ Manufacturing’s Niagara Column Bracket™ allow for the utilization of existing concrete. By being retrofit products, they take away the possibility of error caused by concrete crews improperly setting bolts or brackets.

Properly installed Sturdi-Wall brackets do not have the ability to resist bending moments about the base, as they are a pinned connection. To share my moments read https://www.hansenpolebuildings.com/blog/2012/09/bending-moment/

Concrete Bracket - Drill-SetIn order for the dry-set column anchors to function as designed, the pole building they are to be utilized in should use means other than the bracket itself to resist rotation. This is where the beauty of proper diaphragm design comes into play. Whether from adequately tested and fastened steel roofing and siding panels, or the utilization of structural sheathing such as OBS or plywood, the structural diaphragms can pass wind loads from the laterally loaded surface into the ground, or another diaphragm which eventually passes the applied load into the ground.

Sturdi-Wall brackets should NOT be used in a pole building which does not have adequate diaphragms, such as a roof only structure, unless the loads can be adequately transferred by a system of permanent cable X-bracing or similar.

Already have existing concrete? Then dry-set column anchors may be just the solution.

Dear Guru: Should I Use Concrete Sonotube Foundation?

Welcome to Ask the Pole Barn Guru – where you can ask questions about building topics, with answers posted on Mondays.  With many questions to answer, please be patient to watch for yours to come up on a future Monday segment.  If you want a quick answer, please be sure to answer with a “reply-able” email address.

Email all questions to: PoleBarnGuru@HansenPoleBuildings.com

DEAR POLE BARN GURU: I am planning to build a post-frame house 32×40. I built a 16×16 post-frame barn last Summer as practice and found that I hit bedrock at 2 to 2.5 feet. I know that most post-frame buildings require a 4 foot hole with a concrete footing to keep the post from settling, while also providing lateral strength. I don’t seem to need the depth for settling issues since I’m building on bedrock, however, I lose the lateral strength of a deeper hole. Is there a way to add lateral strength? Also, since I’m not getting that support from a deep enough hole, would it be better to use a concrete sonotube foundation with sturdi-wall brackets to mount my posts?

Thank you – DIGGING IN DOVER

DEAR DIGGING: If you think about it, a sonotube filled with concrete and a bracket on top, is going to provide less lateral resistance than a column in a hole filled with concrete. Depending upon building dimensions, exposure to wind and soil conditions above the bedrock, it is very possible increasing hole diameter and using a complete concrete encasement could do the trick.

As you firm up your plans, we can provide a preliminary hole layout. From this, you can dig the holes and give an exact measure to what point solid bedrock is encountered. This will allow for a design to be created which will minimize the amount of digging and concrete, without negative effect upon your structure.

DEAR POLE BARN GURU: 30×48 pole bldg. was just completed. The 4×6 posts were set on cement cookies 16″ x 4″ every 8′ and then packed with dirt. Is it too late to remedy this situation? Should I dig down to each cookie and pour some cement to encase each post?  The bldg. was just completed last week, so dirt is still freshly packed. What do you suggest? EVENTFUL IN EVANS CITY

DEAR EVENTFUL: It is not too late, but it will involve work which could have easily been avoided. The concrete cookies are not going to be adequate to prevent settling and they do nothing to prevent uplift.

I’d start digging. Make sure the bottom of the hole (directly above the cookie) ends up larger in diameter than the area closer to the surface. You should probably go to two foot diameter and then pour at least 18 inches deep of premix into the hole.