HM20 Bolt in Beam & Column Bolting

my bet is its a spring bolt, like those used on uni-strut, but thats just a guess.

I don't think so, that is a 3/4" bolt and he says it is for a beam to column connection.

as I said, it was a guess I certainly am not sure of this application

HM-200 Chemical Anchor Bolt - Shanghai Horse Construction Co ...
Not a clue if this could be it. I'd just call it an anchor bolt.

these bolts are known as tension control bolts. see link for image and description and use http://www.structuralbolt.com/tca.php

hopes this helps

I would venture a guess that HM in this example vaguely refers to 'high modulus'.

Your description leads me to think of a steel column supporting a steel I-beam,but then a column could also be a RC affair eh?

For other than just being curious, you might check the drawing for a secifications reference page.

According to this page ... http://joints.en.cype.com/joints_bolted.htm there are distinct specifications for the bolts used with this type of construction.That leads me to believe the 'HM' reference is generic,leaving the interpretation up to the fabricator.

Not a good idea but a slick little test question.

HTH

J

P.S. I have both seen & smelled the HM20 bolts Lyn linked to.

Really stinky,sticky,spensive and something to be avoided if possible.The application was a custom fabricated ledger beam of HEAVY construction that was face mounted to a canted,verticle,concrete wall.

The beam was bolted in place,that is erected,braced & aligned into position then the holes drilled & cleaned (beam holes pre-drilled). With the glass tube(s) slipped into the hole the anchor bolt pre-assembled with nuts & washers were driven in with hammer drills.Keeping the oozing epoxy in place (horizontal mounting) while the bolt was driven home had a steep & messy learning curve.

When I worked with a structural steel company we used high strength friction grip bolts (HSFG) which were always torqued.

May be this drawing will give you more information

This is chinese design and beam is bolted to column for staircase-platform.

Please do ask if any additional information is needed.

The bolts shown on this diagram are the equivalent of 7/8" in 1" holes. We would use 15/16" holes. We would usually use 5/8" A307 bolts for stair but I think this is not just for stairs, there are some sophisticated welded connections there. We usually used A 325 bolts in the larger sizes, these days they seem to mostly be Tension control type.

I found this UK site that mentions HM bolts, but I couldn't download the whole thing, web is slow.

chandruu,

"Please do ask if any additional information is needed."

I have one question. Why have you not contacted the person who made the drawing, or the company it was made for.

At this point I assume that you are trying to steal the design and can't ask the legitimate owner for the information.

Once again, why didn't you call or e-mail the origin of the drawing and ask them??

Lyn,

I've already emailed to the company that made drawing. But so far there is no response from them. that's why i'm searching in this forum.

I'll post the reply as soon as i get.

Chandruu:

I tried to magnify your drawing, but I miss detail. Unless I see wrong it is HM22 in stead of HM20. And the hole is 23.5 mm?

When this is for a regular staircase, those bolts and beams are very heavy. What is the purpose? Does the platform carry a lot of weight?

I fail to see the total picture. You have more to show?

Tks.

I am not sure about the letter "H", but it could stand for either "Hexagonal [Head or Nut]. It could also suggest "High Strength". But for the "M", I am almost certain that it stands for "Metric". For the "20", it should be the diameter of the bolt in "millimeters". The bolt itself must be a close equivalent of a 3/4" diameter bolt "English" system. I hope someone out there can solve this "mystery". I consider this as very important,too.

The original post, together with #10, shows that this has nothing to do with concrete anchors. Right there, that makes several responses off topic. "HM20" looks like a generic classification, with some doubt about what the "H" means; however, it could be a proprietary designation. Either way, HM200 does not fit, unless by typo. Stuff that tops out at HM12 does not match. Etc. But then, as #1 noted, the Web is full of useless junk, which is still useless when imported into this thread.

None of this answers the OP, but, as previously noted, the author of the drawings and/or specs could be asked.

HM20 is exactly how you order a Hex bolts of 20 mm diameter in France and F- related suppliers. It is just missing the length expressed after X sign.

Example: HM20 X 40 mm is metric 20 mm with a length of 40 mm. Best wishes for 2014 to all.

Sorry for the delay guys...

Now i got reply from the design providers that HM is same specifications as HT bolts.

thank for all

Hi guys,

I got a reply from the designers that These HM is same as normal metric bolts, only H refers to their own designed bolt.Sorry for the delay, i almost forget to share with you. Thank for all who helped to clarify this .

Regards,

Chandru