A307 vs A325 bolt 4

[upk]

About 3 years ago while casting the upper part of a building. I asked in this forum whether to use A307 or A325 bolt for future roofing addition. Someone recommended A307 over A325.. I couldn't find the thread pertaining to it and the exact reason but it's something along the line of the A325 being high strength and more brittle in connections.. so I used A307. But reviewing their strength now.. I seemed to regret choosing A307.

I'd like to know what application do you exactly use the A307 bolt over A325? Does the A325 require special torqueing in the nuts or longer embedment length.. is there special reason to use the A307?

 

[hokie66]

Just to clarify, and then I am finished with this thread, A307 is NOT "POORLY SOFT", whatever that means. I think jrisebo was being facetious.

You can knock A307 bolts around a bit, but a better solution is to ream (read drill) out the holes in your base plate to give you reasonable tolerance. Were you able to get the epoxy out?

The existing A307 bolts in the corner of the columns, directly adjacent to the corner reinforcement, will take a lot more load than your drilled in anchors.

 

[Ron]

My turn.....

Read Ron's hokie66's post and take it as gospel.

upk...you are obviously not a structural engineer. While I admire your attempts to get things right, you do not have the technical background to adequately implement the advice you've been given here. Please get some competent engineering involvement in this and other similar projects before someone gets hurt or killed. You mentioned that the design engineer was 22 years old. If that is true I would certainly not want him designing critical portions of a structure without more senior engineering overview and supervision.

A307 bolts are fine for anchor bolts. Stop bucking that premise. A325 is a BOLT! It is not a threaded rod and does not serve as an anchor bolt. Yes, it looks like a screw.....a big one.

 

[upk]

i'll go to the structural company and visit the president now.. one of his team asked why I didn't use A325 as metal plate anchor bolt as this was supposed to be standard for high strength in the industry.. that was why they ignored the lowly A307.. at least I know how to ask them later.. many thanks for all the assistance...

 

[upk]

Ok.. had a meeting with the most senior structural engineer of one of the country's biggest structural firms (who did the original building and roof design).. they showed me their manual of high strength steel they used in design of anchor bolts which they specify as A325.

(or see

http://www.pbase.com/techroof/image/161568806

if it won't load)

Upon calling the suppliers.. they fabricate anchor bolts with J end of any length using A325. I asked them if they have other material for high strength bolts.. they said they only have A325 and 4140 but the 4140 is rarely used.. anyone knows if 4140 is good for anchor bolts for my future reference?

This is one of the suppliers I called

http://www.weiku.com/products-image/14671581/A325-Anchor-bolts.html

By the way.. why can't you use the A325 as anchor bolt officially? In the Philippines. We don't have any so called f1554 gr 36 or Gr 55..

How do you recognize an f1554 vs an A325 by physical appearance.. can you recognize which by just looking?

Btw.. they okayed after checking the computations the bigger metal plates with additional bolts my contractor did.. and the poor A307 may be sufficient for my application and they specify high strength A325 in steel columns in low to high-rise buildings.

 

[upk]

Edit.. the supplier said their a325 is made from 1045 steel... so maybe it should be called 1045 steel.. not a325 (which is only reserve for bolts with head?) that can cause confusion.. googling 1045 steel:

http://www.azom.com/article.aspx?ArticleID=6130

So is the f1554 gr 55 made from 1045 steel?

(is a325 made from 1045 steel or from a325 steel or what steel?)

 

[hokie66]

The page you posted is a bolt specification, not specifically for anchor bolts, or holding down bolts as we call them in Australia. A325, or its close metric equivalent Grade 8.8, can be used for anchor bolts, but this is a high strength steel. Rarely is a high strength steel needed for anchor bolts, as the mode of failure is almost invariably the concrete, not the steel. Therefore, A307 or Grade 4.6 anchor bolts are very common and should be used when strong enough, because they are more ductile. J-bolts fabricated in A325 may be available where you are, but I wouldn't trust them because A325 is too brittle to be bent in that way.

 

[JStructsteel]

Also J bolts are not the best application anymore.

Just make sure you dont go in this building when finished, especially during an earthquake.

 

[upk]

Thanks Hokie and others. It finally all made sense.. when bolt is mentioned earlier.. I thought anchor bolts is being meant. But like the word "men" to stand for humankind.. adding a "wo" to "men" become "women".. the meaning changes.. so bolts is general terms and anchor bolt is part of the genetic bolts like women are part of men (meaning human).

I bought the different bolts to try to distinguish them (see picture above). I don't have any a325 anchor bolt.

The store says the left one is the A307.. is there any steel even weaker than the A307? because there is lurking fear it may be weaker.

I also understand from Hokie:

1. Why structural engineers didn't emphasize to use grade of steel in anchors because concrete failure occurs first before the yield strength is reached.

2. Two years ago when the engineer told me to add anchors and didn't specify grade. I asked the store what was available. They mentioned A307 and a325. And I asked here at eng-tips which was better. Someone answered A307. So I got the A307 two years ago and days ago when I visited the store and the owner said they had both A307 and high strength a325.. I seemed to regret why I didn't get the a325.. i forgot why I got the a307 and tried to find the thread but couldn't.. this was why I posted days ago to request enlightenment. Now I'm enlightened.. and feel better for not making mistake in buying a307 two years ago.

 

[BadgerPE]

The attached article might bring some additional clarity to the topic for you.

 

[JStructsteel]

You mean A325

 

[TLHS]

hokie, you wouldn't be able to get a J-bolt in A325, because the A325 spec is specifically for hex headed bolts. If it's rod or anything other than a hex headed bolt it isn't A325.

If it's something other than a hex head bolt with the same material specs, it's A449. It apparently has lower quality control requirements than A325, though.

http://www.portlandbolt.com/technical/specifications/astm-a449/