Page 56 - Modern Steel Construction (April 2019)

Fig. 10. Example of bolt
spatial considerations. Fig. 11.

t-up of the web connection plate, as shown in Figure 10. This, in ematically) but the supporting member may be overstressed as well.

combination with relatively narrow beam anges, can cause bolt Loading for joint A-2 in Table 1 represents such a case.
fouling or entering and tightening issues. In this case, one pos-

sible solution is to use a longer pull-off for the beam ange bolt Table 1. HSS-beam-to-wide-fl ange-column
group (again, indicated in Figure 10). Just be sure to consider the moment connection design loads.
stability of the ange connection plate for pull-offs on plates in Joint A z V x V y M x M y M z

compression. Note there are myriad issues in regard to entering
and tightening. Figure 10 shows just one condition. Coord. (kips) (kips) (kips) (k-in.) (k-in.) (k-in.)
13. Keep analysis and boundary conditions in mind. You A-1 35 15 42 95 0.50 0.25
should always carefully consider the degrees of freedom required A-2 * * * * * *
for the desired structural behavior and performance during analy- *Provide available axial, shear or moment strength of HSS.
sis. Some commercially available software assumes no releases in
the default condition, so be sure to provide releases where appro- 14. Use extended shear tabs for connecting braced beams
priate. Figure 11 shows an example of a typical hollow structural to column webs. When installing a braced beam between two

section (HSS) beam-to-wide- ange-column connection. The column webs, the beam needs to be slid down. Due to the presence
loading chart in Table 1 suggests axial load, shears and bending of gussets, swinging a braced beam inside the column is a dif cult

moments for all three axes. Notice that the connection at joint A-1 task for the erector. And the presence of cap plates or stiffeners in
requires design moments of M y and M z equal to 500 lb-in. and 250 column webs can make installation nearly impossible. Extended
lb-in., respectively, in combination with the other required loads. shear plate connections offer many advantages like avoiding mem-
This can complicate connection design and drive up design and ber coping and less detailing erection and detailing required. A
effort time, as well as the cost of the steel package. For the typical major concern for the designer is to design an extended tab for
structure, releases are appropriate. If all of the degrees of freedom the moment at the group of bolts due to eccentricity and transfer
truly are required, so be it. only shear load at the center of the column—which makes the tab
When communicating connection loading information to the thicker and requires more bolts. If precise loads are supplied by
delegated connection designer, it is best to provide the loads required the engineer of record (EOR) these connections can be designed
from analysis. Simply requiring a connection to develop the strength lighter as compared to those designed for generalized UDL crite-

of the member being connected is not necessary in most cases. This ria. If extended tabs are speci ed at the start of the job, the beams
can be signi cantly exacerbated when no releases are provided. Not can be procured in lesser lengths (up to the column ange edge)

only is the member being connected overstressed (at least math- thereby lowering material requirements.
56 | APRIL 2019