This site was developed and is maintained by Nucor Corporation's Vulcraft Group as a service to our customers. If you have questions, comments, or suggestions concerning our web site, please let us know.
FAQs...
If your question isn't listed below, please ask us!
GENERAL QUESTIONS
1.
How do I become a customer of
Vulcraft?
2.
How do I find out what my
projected delivery date is for ordered material?
JOIST & JOIST GIRDER DESIGN
QUESTIONS
1.
Are
joists and joist girders designed to the AISC-ASD Code or AISC-LRFD
Code?
2. Do joist welds meet AWS D1.1 Code requirements?
3. How do you specify joist girders with different joist loads
or different joist
spacing?
4. What information is required to specify bowstring Joists?
5. When should a KCS series joist be specified?
6. Can bridging be removed when it interferes with other trade
work?
7. Are there special bridging requirements for bottom chord
bearing or
cantilever joists?
8. Does Vulcraft have recommended moment connection details
for joists
and joists girders?
9. Are there special requirements for long top chord
extensions on K-series
joist?
10. Can you design joists for a moving point load at top and
/or bottom
chords?
11. Why does the diagram for the joist substitutes with a
cantilevered end
show the cantilever and the main-span
being the same length?
12. Are there special design factors that must be considered
for scissors and
arched joists?
13. Can joist seats be used to transfer lateral loads into the
supporting
structure?
14. How much axial load can joist girder seats transfer into
the supporting
structure?
JOIST & JOIST GIRDER LOADING QUESTIONS
1.
How
should special loads for joists or girders be specified?
2. If special loads are required, do equivalent K or LH
designations need to
be given?
3. How can the capacity of an existing joist be determined?
JOIST & JOIST GIRDER SIZE
QUESTIONS
1.
What is the maximum length
and/or depth of a joist or joist girder that can be
delivered in one piece?
2. What is the minimum length joist that can be built?
COMPOSITE JOIST QUESTIONS
1.
What design information is required to specify a composite joist?
DECK QUESTIONS
1.
Is
Vulcraft 3N-deck Factory Mutual approved?
2. Does Vulcraft supply insulation for deck?
MISCELLANEOUS QUESTIONS
1.
What information does the Vulcraft joist tag show?
2. What paint options are available for joist or deck?
3. Why is the weight per foot of the same joist different
between the load
tables and the Economical Joist Guide?
4. Why is there a 550 pounds per foot capacity limit in the
K-series joists?
5. Why is there not a chart to show the maximum duct openings
for the
LH-series joists?
GENERAL QUESTIONS
1. How do I become
a customer of Vulcraft?
You must contact the Vulcraft sales office nearest you. Vulcraft reserves the right to qualify customers.
2. How do I find out what my projected delivery date is for ordered material?
When an order
is placed, it is scheduled in a specific Fabrication week. Once
the material is fabricated, our shipping department will call you
and set up a specific day for delivery. We can not determine an
actual delivery date until the material has been fabricated.
[
back to top ]
Joist & Joist Girder
Design Questions
1. Are
joists and joist girders designed to the AISC-ASD Code or AISC-LRFD
Code?
Joist and joist girder design conforms to the Steel Joist Institute specifications, Allowable Stress Design only.
2. Do joist welds meet AWS D1.1 Code requirements?
Joist welds conform to the Steel Joist Institute specifications, Allowable Stress Design only.
3. How do
you specify joist girders with different joist loads or different
joist
spacing?
In this situation, a special load diagram must be provided showing the required loads and their location on the girder.
4. What information is required to specify bowstring Joists?
In addition
to loading information, the joist depth at the ends and center and
the bend radius for the top chord must be provided.
5. When should a KCS series joist be specified?
When point load locations vary between joists or the locations for point loads are not known, a KCS series should be used. The KCS series joist can also be used when non-uniform loading conditions exist. The specifying professional must calculate the maximum moment and shear caused by the various loading conditions and select the KCS series joist that provides the required moment and shear capacity. This information is more specifically addressed in the Vulcraft Steel Joist and Joist Girders catalog.
6. Can bridging be removed when it interferes with other trade work?
Bridging may not be removed as a general rule. However, in certain instances, the Vulcraft engineer may be able to recommend modifications to the bridging requirements. Review any conflicting conditions with the Vulcraft engineer to determine what options are available.
[ back to top ]
7. Are
there special bridging requirements for bottom chord bearing or
cantilever joists?
There are special bridging requirements when bottom chord bearing is required or a joist has a full depth cantilevered end condition. A row of diagonal bridging is required to be located near the support for lateral stability. This bridging must be installed as the joists are set in place.
8. Does
Vulcraft have recommended moment connection details for joists
and joists girders?
The most efficient detail allows for the top moment plate to be welded to the top chord of the joist or girder and the cap plate of the column. This requires the joist or girder seat to be supported by a haunch or seat angle. Additionally, the bottom chord extensions must be welded to the stabilizer plate on the column. The size of the top moment plate, seat angle or haunch, stabilizer plate and all required welds are to be determined by the specifying professional. For recommended details, refer to the Vulcraft Steel Joists and Joist Girders catalog.
9. Are
there special requirements for long top chord extensions on K-series
joist?
Typically bearing seats deeper than the standard 2 ½" seats are required. When the extension gets beyond 1’-6", seats depths up to 5" or more may be required to design the extension for the required load. Long top chord extension conditions should be reviewed with a Vulcraft engineer for guidance on the required seat depth.
[ back to top ]
10. Can you
design joists for a moving point load at top and /or bottom
chords?
Yes, the joist design is based on the worst condition for each member in the joist for the load applied anywhere along the length of the joist.
11. Why
does the diagram for the joist substitutes with a cantilevered end
show the cantilever and the main-span
being the same length?
By balancing the lengths, the force is applied to the supporting joist would be balanced by the applied load to the joist for the same loading condition. It is possible to have different lengths of the cantilever and the main-span; however, the supporting joist design must be reviewed.
12. Are
there special design factors that must be considered for scissors
and
arched joists?
These types of joist configurations will produce a horizontal force at the supports. The ability of the supporting structure to resist this horizontal load must be considered by the specifying professional.
[ back to top ]
13. Can
joist seats be used to transfer lateral loads into the supporting
structure?
Joist seats can be designed to transfer lateral loads into the supporting structure, however there are limitations. This issue must be looked at on a case by case basis and should be reviewed with a Vulcraft engineer.
14. How
much axial load can joist girder seats transfer into the supporting
structure?
Axial loads
can be transferred into a column through the joist girder seats.
The magnitude of load that can be transferred depends upon the
chord and seat member sizes used in the girder. This information
is more specifically addressed in the joist girder section of the
Vulcraft Steel Joist and Joist Girders
catalog. As with any special
condition, this issue should be reviewed with a Vulcraft engineer.
[
back to top ]
JOIST & JOIST GIRDER LOADING QUESTIONS
1. How
should special loads for joists or girders be specified?
The clearest way is to provide load diagrams or joist load schedules.
2. If
special loads are required, do equivalent K or LH designations need
to
be given?
If desired, the specifying professional may request a standard joist that has been determined to be adequate to support the special loading condition. When this is done, the special loading condition should not be provided.
Alternatively, the actual loading requirements, including the special loading conditions, may be specified and the joist will be designed for those specified loads.
[
back to top ]
3. How can the capacity of an existing joist be determined?
The first information to look for is the manufacturer's name, job number, and mark number from either the metal joist tag found on the joist or the erection placement drawings for the building. The manufacturer can usually determine the loading the joist was designed for with this information.
If this information cannot be found, field measurements must be made. The top and bottom chord angle sizes must be measured along with the joist depth. An approximate capacity of the joist can be determined by calculating a section modulus with this information and using a reasonable value for allowable compression.
Additional
information for evaluating existing joists may be found in the "Sixty
Year Manual",
available through the
Steel Joist Institute.
This manual contains all of the Steel Joist Institute's
Specifications and Load Tables starting with the Institute's
inception in 1928, continuing through 1988. A section of practical
information is of great assistance when analyzing existing
structures. Included is a listing of various building documents
required and what use they can be, building site information and
equipment needed, step-by-step investigative procedures, and other
time saving data.
[
back to top ]
JOIST & JOIST GIRDER SIZE QUESTIONS
1. What is
the maximum length and/or depth of a joist or joist girder that
can be delivered in one piece?
Vulcraft’s fabrication ability on depth and length of joists typically exceeds that which may be legally permitted for delivery. Please contact the Vulcraft location that will be fabricating your project to discuss any restrictions.
2. What is the minimum length joist that can be built?
From a
practical and economical standpoint, Vulcraft does not recommend
using joist for spans less than 6’-0". For spans 6’ or less
Vulcraft recommends using the VS (Joist Substitute) series.
[
back to top ]
COMPOSITE JOIST QUESTIONS
1. What
design information is required to specify a composite joist?
Joist depth, span and adjacent joist spacing (for exterior and interior conditions), deck type, slab depth above deck, concrete unit weight, concrete F’c, stud diameter, stud length and composite design loads. Composite design loads include:
- Non-composite Dead Load (concrete, joists, deck and bridging)
- Construction Live Load (A suggestive minimum is ½" additional concrete plus five 200 lb. Workers.)
- Composite Dead Load (Includes partitions, mechanical, electrical, fireproofing, floor covering and ceiling.)
- Composite
Live Load (Reduced design live load applying applicable code
reductions.)
Refer to the current Vulcraft Composite Joist catalog for a more complete discussion of this issue.
[
back to top ]
DECK QUESTIONS
1. Is
Vulcraft 3N-deck Factory Mutual approved?
Yes it is. Please see our Vulcraft Deck Catalog for more information.
2. Does Vulcraft supply insulation for deck?
Vulcraft does not supply thermal insulation.
For accoustical deck, the Vulcraft price includes the glass fibre sound absorbing batts delivered to the
job-site by our supplier.
[ back to top ]
MISCELLANEOUS QUESTIONS
1. What
information does the Vulcraft joist tag show?
The metal tag wired to each joist shows the job number, mark number and plant location. The bundle tags shows standard erection warnings, plant location, job number, list number, part quantity, part number, paint color, date and time built.
2. What paint options are available for joist or deck?
Joists and joist girders are provided with no paint or either a red or gray shop primer.
Deck is provided with either no paint, red, gray or white shop primer, or galvanized
NOTE: Availability of red paint is limited to certain Vulcraft
divisions.
NOTE: The shop primer is not intended to be a finish coat and
must not be expected to perform like one.
Please contact the Vulcraft location that will be fabricating your project to discuss available paint options.
3. Why is
the weight per foot of the same joist different between the load
tables and the Economical Joist Guide?
The weights shown in the load tables are from the Steel Joist Institute and are based on the average weight of that joist for the industry. The weights shown in Economical Joist Guide are the based on Vulcraft only.
[ back to top ]
4. Why is there a 550 pounds per foot capacity limit in the K-series joists?
The Steel
Joist Institute limits the capacity of standard K-series joists to
550 pounds per foot. It is possible to get a K-series joist with a
capacity greater than 550 plf; however, this joist must be called
out as a special and a loading diagram provided.
5. Why is
there not a chart to show the maximum duct openings for the
LH-series joists?
There is no chart because the panel sizes for these joists have many factors that will govern how the panels are set. Specific requirements for clearances in a given joist should be reviewed with a Vulcraft engineer.
[ back to top
]