Spider Fitting Glass Curtain Wall Test Prototype Page 3 of 14
Edward C. Robison, P.E.
10012 Creviston DR NW 253-858-0855
Gig Harbor, WA 98329 fax 253-858-0856
email: elrobison@narrows.com
SEISMIC LOADS:
Seismic loads typically are much less than wind loads
FP =[(0.4*aPSDSIP)/RP][1+2z/h). ASCE/SEI 7-05 13.3.1
The primary seismic concern is the curtain wall’s capacity
to accommodate the story drift of the building frame as
required in ASCE/SEI 7-05 13.5.9.
In accordance with ASCE/SEI 7-05 12.12 and Table 12.12-1
the allowable drift is dependent on the construction type and
occupancy category.
The highest allowable drift is:
Δa = 0.025hxx
Thus the maximum drift capacity of the curtain wall (I =
1.0) is:
Δa ≥ I*1.25*0.025hxx = 0.03125hxx maximum required
For the 20’ height Δa = 0.03125*20’*12”/ft = 7.5”
Δa ≥ I*1.25*0.010hxx = 0.0125hxx minimum required
For the 20’ height Δa = 0.0125*20’*12”/ft = 3”
Maximum tested = 4.5” = 0.01875hxx