Column base plate A. bolt in canada

[dgkhan]

I am aware of that in USA we need minimum 4 anchor bolts for steel column base plate as per OSHA. Any one knows what is requirement in Ontario, Canada. Any local code reference will be appreciated.

 

[kslee1000]

I think it is time to call the local building authority, or get a copy of local/national building code.

Per my understanding, OSHA requires 4 bolts is out of concern of framing stability during erection/construction, for which has caused many tragic events, and lifes. It is worthy to take note on that when deal with steel constructions.

 

[BAretired]

I don't know if there are any code requirements regarding the number of anchor bolts in a baseplate. Usually, four is minimum but for minor columns bearing on narrow foundations, two anchor bolts may be used.

Best regards,

BA

 

[beton1]

I agree with BA; I live and work in Ontario and have seen
and used two anchor bolts often. I am unware of any specific code requiring '4 anchors'.

 

[dik]

There is no requirement in Ontario, Manitoba or Saskatchewan for 4 anchor rods. I don't know what the situation would be if someone were injured and it was shown that for safety reasons 4 would be required and is common to other jurisdictions.

Dik

 

[amustEIT]

When the column is only carrying vertical gravity loads.
The connection is required only to hold the parts in line, and two anchor bolts are generally sufficient

 

[ali07]

We provide both 4 and 2 Anchor Bolts in our schedule drawings. Contractors most of the time for 2 or more than 2 stories go for 4 anchor bots for practically holding the columnn at site or due to construction loads during erection. For single story except at vertical brace locations, they usually follows 2 anchor bolts at most of the location. Most of the time, practical considerations are more important than codal requirements.

 

[kslee1000]

ali07:

I agree with you on practical vs code. However, if you are in the US, beware the consequences of tragic events that involving OSHA violations. (Note: some of OSHA regulations are mandatory, some are not. Visit its website to post a question, or check with persons that familiar with OSHA rules.)

Does Canada have government agency similar to OSHA?

 

[beton1]

For kslee; Yes, in Ontario there is the "Occupational Health and Safety Act and Regulations for Construction Projects" ie., 'Green Book'; Construction Safety Association of Ontario is generally geared for contractor training. The Ministry of Labour (say equivalent to a State agency) for Ontario has the enforcement power and has officers who do site (random?) visits. In the instance of this thread (about anchor bolts, and temporary/erection stability),it generally falls under the responsibility of the steel erector/faricator to install temporary bracing etc. and to work safely etc. If something drastic happens, then there might be a new regulation; similar to tower crane collapse(s) in NYC.

 

[kslee1000]

beton1:

Thanks for the info.
OSHA has broad powers to enforce its regulations over every industrial settings, construction works, and pollution issues. Many of those regulations are not in the code, but to be complied. Otherwise the business may face hefty fines, or litigation brought by the government.

Regarding the 2 bolts/4 bolts issue, I vaguely remember there were several steel structure collapses during erection, that injured, or caused death of several construction workers. I believe the main cause of most collapses was lack of, or inadequate, lateral bracing/support, however, the 2 bolts pattern was cited along many other deficiencies, but was deemed easier to amend to be fool-proof. Thus given the birth of 4 bolts mandate. Well, I guess this mandate have caused heart burns and headaches of the pre-fabricated building manufactures, and the engineers that have to deal with them. I haven't heard any such (collapse) event lately, maybe it does improve construction safety.

 

[ali07]

But on the other hand, be careful 4 bolts attract moment, good for structure unless the connection of column to base plate and foundation/pier is designed for that, which actually most of the times assumed as pinned.

 

[kslee1000]

ali07:

Good point. Inevitably, 4 bolts pattern will draw some moment, however, it is far from fixed condition. Remember that only a small amount of rotation is needed to classify the connection as pinned. I could be wrong, 4 bolts pattern is used quite frequently and designed as pinned support, even prior to OSHA mandate. To increase moment capacity, it will require much more to accomplish that. But you are right, be prudent when column size vs base layout is close to the boder line.

 

[BAretired]

The only reason to use more than two anchor bolts on a baseplate is to develop restraint at the base of a column. There are many cases where two anchor bolts are adequate.

During the erection process, columns are not fixed at the base. Whether two, four, six, eight or twelve anchor bolts are specified, standard practice is to provide steel shims under the center of the column with no nuts on the anchor bolts. During erection, columns are not fixed against rotation at the base. The erectors are assumed to know what they are doing and provide the necessary bracing to stabilize the structure during erection.

Building code administrators should enforce the building code. OSHA should enforce safe construction practices but should not be permitted to meddle in building code matters (in my humble opinion).

Best regards,

BA