Question

please help with number 1

A w14x120, W14x109, and a W16X100 are being considered as sections for the steel column with a length of 9 meters. The column is pinned at the upper end and fixed at the lower end. Use A36 steel. Fy 248 MPa. Use K(pinned) 1.0 and K(pinned-fixed) 0.7. If the total axial demand is 3500 kN, which among the sections is the most efficient? Use LRFD Section Properties: W14x120 1. Ag 22,800 mm2 d 368 mm bf 373 mm tw 15.0 mm tf 23.9 mm Ix 574x10 mm ly 206 x10 mm Kdes 39.1 mm Weight 179 kg/m Section Properties: W14x109 ly 186 x10 mm Kdes 37.1 mm Weight 162 kg/m Ag 20,600 mm 13.3 mm d 363 mrm bf 371 mm tf 21.8 mm Ix 516x10 mm Section Properties: W16x100 Ag 19,000 mm2 14.9 mm bf 264 mm ly 77.4 x10 mm kdes 35.3 mm d 432 mm tf 25 mm Ix 620x10 mm Weight 149 kg/m 2. If your selected column in Problem 1 is to be braced at mid-height, determine the new nominal capacity of the column. How much is the percent increase in nominal capacity? 3. If a built-up section can be used for the column in Problem 1 provided that there will be no bracings t-22 mm 8 mm 356 mm b, -375 mm a) What is the reduction factor Q due to slender elements? b) What is the axial capacity of the built-up section using LRFD? c) Calculate the weight per meter of the section in kg d) Which is more efficient, the built-up section or the W-shape section selected in Problem 1? Explain your answer e) Based on your answer in (d), would you always recommend column sections with non- slender elements?

Answer 1

vern LO i 니 x 120.ulu乍107 and a , uoi6x1bb aYe be, n conideed as Secon of the stee column 49 MPa A36 tee) The lesi conprecclve sen, ー>-he allowaLie Pnløc are detevmined ac folows Value obtain ed Lased on the states of flexua uig and flevuval- pplfcable limit

Column selecf.on-ASTM 수가 3 CNendle 6S tneY A1.CC. Manua) table -l »itth a eedve tength, the leasth chope oth an stenth 수어 Fo' built up çection bu㈥íng class C 려28 D x 164-62 Ag冫曰0,600 mm2

1u.99