long span steel joists

huangyhg

long span steel joists
hi guys,
what is difference between "open web steel joists(owsj)" and "long span steel joists(lssj)" other than the difference of span?
what is min span requirement for lssj? or when we have to have lssj?
thanks,

it's all dependent on your loading.  long-span joists are  stronger.  in my vulcraft catalog's "economical joist guide", 22' is the first span for which an lh joist is listed.
one difference to consider is in the detailing.  long-span joists have a 5" standard seat depth, vs. 2 1/2" seat depth for k-series.
rholder98,
does the depth of joist shoe depend on loading or type of joist( owsj or lssj)?
to my knowledge, this shoe depth is just to clear web from beam and to reduce eccentricity at top chord/web junction.
another: lh joists can have loads greater than 550 plf.  k-series cannot.
lokstr:  the seats are based on the type, which you select based on loading.  k-series seats require minimum 2 1/2" depth.  lh minimum is 5" deep.  the depths shouldn't vary with loading, but will vary with increased slope.  and you can specify custom seat depths, as long as you don't try to get smaller than the minimum.  this is important to keep in mind if you are mixing the two different types of joists.  to keep a level roof or floor, you would need to drop the supports 2 1/2" at lh joists, or specify a deeper seat for the k series.
ucfse:  excellent point.  that's a critical difference.
rholder98,
thanks for great info.