11.07.2015 Views

AISC LRFD 1.pdf

AISC LRFD 1.pdf

AISC LRFD 1.pdf

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

120 PONDING [App. K2.ered as consisting of secondary members supported on an infinitely stiff primarymember. For this case, enter Figure A-K2.2 with the computed stress index U s . Thelimiting value of C s is determined by the intercept of a horizontal line representingthe U s value and the curve for C p 0.The ponding deflection contributed by a metal deck is usually such a small part ofthe total ponding deflection of a roof panel that it is sufficient merely to limit itsmoment of inertia (per foot (meter) of width normal to its span) to 0.000025 (3 940)times the fourth power of its span length. However, the stability against ponding ofa roof consisting of a metal roof deck of relatively slender depth-span ratio, spanningbetween beams supported directly on columns, may need to be checked. Thiscan be done using Figure A-K2.1 or A-K2.2 using as C s the flexibility constant for aone-foot (one-meter) width of the roof deck (S = 1.0).Fig. A-K2.2. Limiting flexibility coefficient for the secondary systems.<strong>LRFD</strong> Specification for Structural Steel Buildings, December 27, 1999AMERICAN INSTITUTE OF STEEL CONSTRUCTION

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!