huangyhg

astm a513 guardrails
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,
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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.
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.
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.
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
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%)fff">
[color red]i'd use 29,000 ksi for e[/red] ???????
hope this helps
robert kazanjy

looks like it (a513) lies in between a36 & a572, comparatively speaking. for certainty, check it out directly from astm.
also, is this for transportation project? if so, check aashto for spec. on guardrails.
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

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