Question

Steel Design

3. Given a. W27X84 A992 Steel beam is simply supported over a 25' FT beam length. b. The compression flange of the beam is fully braced along the beam length. c. A uniformly distributed service dead load of 2.5 KLF. d. A uniformly distributed service live load of 3.5 KLF. e. A live load deflection limit of L/360. A dead live load deflection limit of L/240. f. Neglect the self-weight of the beam in all calculations. Determine: The flexural capacity (pMn) of the W27 beam showing full calculations The live load deflection and dead+ live load deflection of the W27 beam showing full calculations a. b. c. Determine whether or not the W27X84 meets the conditions required for strength and serviceability. If not, select the lightest beam available that satisfies both the flexural strength and serviceability requirements? Show full calculations.

Answer 1

GIVEN DATA Properties of Steel section Grade of steel Beam Section Span of the beam, Plastic section modulus Moment of inertia, Width/thickness ratios A 992 W 27x 84 25 ft Zx244 in 4 = 2850 in 4 b/2tf7.78 htw52.7 wo- 2.5 kip/ft W13.5 kip/ft Uniform service dead load Uniform service live load CALCULATIONS Yield stress of steel Modulus of elasticity 50 ksi E29000 ksi Maximum factored bending moment w, = 1.2 W D + 1.6 w - 8.6 kip/ft Factored udl Maximum bending at mid span due to udl 671.9 ft.kips heck for compact secti 65 9.19 1 OK 2t 640 90.511 OK Hence, the section is COMPACT heck for design capac Design strength of beam 0.9 x 244 5012 915.00 ft-kips > 671.9 ft-kips [:MJ Hence, SAFE Check for deflection Service live load w3.5 kip/ft 384EI 0.372 in< 0.83 in L/360] Hence, SAFE in defelection

Service deadlive load w6 kip/ft W- 1SwL 384EI 0.638 in 1.25 in [=L/240] < Hence, SAFE in defelection