Anchor Bolts: A36 or A307? 1

[jopalu]

AISC 9th, says A307 has a higher Tensile strength, as well as higher allowable tensile and shear loads as compared to A36. I can find neither a Yield strength, nor an Ultimate value for A307. Why?

Other than the slight difference in values, what advantage does one have over the other?

Thank you ...

 

[Bagman2524]

I thought A307 is the bolt designation for A36 steel. A36 is for structural shapes.

 

[cvg]

Check PP 4-4, Table 1-C - it lists A36 for threaded round stock. I believe A307 is for bolts and studs only, not all thread.

 

[sundale]

I agree with cvg: A36 is all thread and a 307 is headed (bolt). I had a steel fabricator rub my nose in this distinction a few years ago and will not forget which is which.

The ASTM callouts for all thread anchor bolt type stock should be F1554, Gr. 36 or A36.

 

[UcfSE]

A307 has no specified yield strength, only tensile strength. The tensile strength for A307 is slightly higher than that for A36. You may find these strengths in the connections chapter of the AISC 9th.

 

[JStephen]

I was thinking that one of the grades of A307 (grade C, if I remember right) actually WAS A36- I'll try to check when I get back in the office.

 

[Dinosaur]

I recommend you look into ASTM F1554 Anchor Rods. This is the most up to date spec on anchor rods of which I am aware. These come in three strengths: 36ksi, 55ksi and 105ksi. Good Luck.

 

[JStephen]

A307- Grade A has minimum tensile strength of 60KSI.
A307- Grade B has tensile strength of 60KSI-100KSI.
A307-Grade C has "properties conforming to" ASTM A36- tensile strength of 58-80 KSI.

Yield is not listed for Grades A and B. There are hardness requirements for Grades A and B, as well as specified tensile requirements for each bolt size.

 

[jopalu]

I just got off the phone with Birmingham Fastener, Inc. which is one of the major structural headed bolt and threaded rod manufacturers of only a few in the nation that most of the nations fabricators will puchase anchor bolts from. I know this because I used to be an estimator at a local steel fabricator that used to purchase anchors from Nashville Bolt which is no longer in businesss, and now this fabricator uses Birmingham.

Apparently, as JStephen stated, MOST of the A307 bolts AND threaded rod is made from A36 steel. A307 Gr C, is a recommended specification that simply involves less certificationary paperwork that involves certain testing procedures which, unless required or specified by the engineer, can be avoided, thus costing less and producing virtually the same A307 material specification. Does anyone know anything more, either supporting, or contrary to this alleged claim by Birmingham Fastener?

Apparently, A36 and A307 are available in either threaded rod or headed bolts. AISC is not always accurate or current considering the 9th Ed. is over 15 years old...

We need to check with your local fabricator and national manufacturers to insure that our specifications and intentions compliment what is actually available and what the local fabricator is willing to work with, providing there is room for flexibility.

 

[jopalu]

JStephen,

Where did you get your info from? I can't find it in AISC 9th Ed.

 

[Bagman2524]

ASTM's website, astm.org, has the info provided by JStephen above. Just do a search on A307. The spec is titled "Standard Specification for CS Bolts & Studs 60,000 psi tensile strength. In addition to what JStephen has listed, Grade A is for general applications, Grade B is for flanged joints in piping and Grade C is for non-headed anchors

 

[JStephen]

I think the Grade C is intended for those cases where you use A36 rod and make custom anchor bolts out of it- typical for big anchor bolts. (IE, using round rod, threading one end, bending or putting washer plate on other end- not all-thread rod assemblies). The data above is from ASTM A307-04.

 

[vincentpa]

AISC has changed the name to "Anchor Rods" instead of "anchor bolts." AISC also punts on the design to ACI Appendix D. ACI 318 Appendix D refers to ASTM F1554 which gives three strenghts: 36 ksi, 55 ksi, and 105 ksi. ACI and AISC recommend designating the "Anchor Rods" as "ASTM F1554 Grade 36 (55 or 105)". For more information, see the new AISC Design Guide 7 Industrial Buildings, ACI 318 Appendix D, and PCA Notes on ACI 318. However, I'm sure by next week, they'll change it to something else.

 

[aiden]

A36 generally refers to Carbon structural steel, this could not be directly comparable to A307 which is for steel bolts and studs, each has different manufacturing processes and that metallurgical properties are slightly different.
an A36 steel can be threaded to make a bolt (irregardles of whether there is a head or just a stud) but its properties is still the same which is comparable to A307GrC.
there used to be a specs for threaded round stock (i cant remember) and its also comparable to A36 grade. this was mainly used for non-standard sizes (at present F1554 is being used)

A307 Gr. A are manufactured with specified strength 60ksi to be used for structural connections not requiring high strength bolts while Gr. B are mainly intended for piping flange connections without elevated temp requirements, high strength or environmental requirements.

- structural (design, detailing & fabrication)