ASTM A513 Guardrails

[StructuralEngGuy]

Hi everyone,

I've been given a steel shop drawing for guardrails to check. I noticed the steel fab is using 1-1/2" diameter ASTM A513 grade tubes. I looked in my steel manual and could not find this grade of steel. A quick google search for the yield strength gives a range of 30-80 ksi. Anyone use this grade before and know what the yield strength is? I'm trying to see if it would be acceptable to resist handrail loads.

Thanks,

 

[kslee1000]

I have never ask why, but I think there must be reasons that AISC specify certain metals as structural grade material, and left out rest majority of metal products. Find out.

 

[Ron]

SEG...check with the fabricator. That tubing is available, as noted in a variety of yield strengths. The fabricators I deal with use a 50 ksi yield material (pretty much the only way you can get a 1-1/2 inch tube to handle the lateral loads). Anything over a 4-foot spacing gets close.

Ask them to submit mill certificates or at least a purchase order for your documentation, showing the 50 ksi material.

 

[bridgebuster]

What do your plans & specs call for or is the design left to the discretion (or imagination) of the contractor?

NYSDOT specs generally require 50 ksi for tubes used as part of a guide rail systems.

 

[kslee1000]

Is yield the only concern in specifying, selecting structural material? Or there are something else need to be concerned with (other than cost)?

Range of Yield Strength of a few Metals:

Aluminum - 40 to 70 ksi
Bronze - 25 to 100 ksi
Copper - 8 to 110 ksi
Nickel - 20 to 90 ksi
Steel - 30 to 100 ksi
Steel Wire - 40 to 150 ksi

 

[kslee1000]

A web search turns out a discussion record below.

"ASTM 513 has a Type 1 or 2...the Fy & Fu depend on the alloy (C1010 or C1020), the tube OD & the wall thickness

the following material properties ranges apply

for 1010

Fu - 45 ksi to 48 ksi
Fy - 35 ksi to 40 ksi

for 1020

Fu - 55 ksi to 50 ksi
Fy - 36 ksi to 40 ksi

tubes .75" OD & smaller have the higher strengths & lower elongations (~15%)

.75" OD & larger with heavier walls have the lower strengths & higher elongations (~25%to 35%)

I'd use 29,000 ksi for E[/red] ???????

hope this helps
Robert Kazanjy"

 

[kslee1000]

Looks like it (A513) lies in between A36 & A572, comparatively speaking. For certainty, check it out directly from ASTM.

 

[kslee1000]

Also, is this for transportation project? If so, check AASHTO for spec. on guardrails.

 

[COEngineeer]

Are you sure you are not only checking the connection to the concrete or something like that? Usually DOT projects have certain guardrails they want to use but I never check the actual guardrails, I just check for example the bridge supporting the guardrails.

Never, but never question engineer's judgement