Understanding LRFD and ASD: Key Problem Solutions Explained
School
University of Dayton**We aren't endorsed by this school
Course
CEE 411
Subject
Economics
Date
Dec 10, 2024
Pages
3
Uploaded by GrandFlowerJackal15
Problem 6-1 LRFD P =1.2(135)+1.6(205) =490k Assume £ =60 B ¢F, =34.6ksi Table 4-14 P, 490 = =14.16in’ e ¢F, 34.6 ASD P =135+205=340k Assume 5 =60 B F a" =23.0ksi Table 4-14 B, 340 . -4 -2 _1478in’? e F, 230 Q Try W10x 60 (4 =17.7 in’. r, =2.571n) c r ¢F, =26.88ksi Table 4-14 ¢P =26.88(17.7)=4758k <490k NG L 18(12 . — = (—7) =84.05 (F, =50ksi) =17.89 ks1 Table 4-14 el e ~=17.89(17.7)=316.7k <340k NG o) Try W10x68 (4=19.91in’, r, =2.591n) c r 2.59 ¢F, =27.08ksi Table 4-14 ¢P, =27.08(19.9) =5389k >490k |Use W10x 68, LRFD) L _18(12) =83.40 (F, =50ksi) =18.02ksi Table 4-14 N O | =~ =18.02(19.9)=358.6k >340k OK Use W10x 68, ASD| Problem 6-6 LRFD P, =1.2(90)+1.6(140) =332 k (Use W10x 49, LRFD| ¢P, =382k >332k Problem 6-9 LRED P =12(145)+1.6(150) = 414 k L =12(15)=18ft W10x54 LRFD ¢P =422k > 414k =P, ASD P =90+140=230k L =181t From AISC Table 4-1a Use W10x49. ASD £=254k>230k Q ASD P =145+150=295k L =12(15)=18 ft WI10x60 ASD i=316k>295k=Pa Q
Problem 6-16 (a) LRFD ASD Problem 6-14 P, =12(150)+1.6(225) = 540k P, =150+225=375k L =KL=10(20)=20f L =KL=1.0(20)=20f LRFD Solution Size 9F, Ril w8 (None work) Size Q P =1.2(165)+1.6(250) =598 k W10x77 s48k W8 (None work) . W10x88 423k F. =50ksi K =06 — W12x65 42k v x 5 L =251 W14x82 545k otk _ - . HP12x 74 599k W14x90 583k Try(L,), =0 (continuously braced by wall) PR 81k HPI2x74 398k HP14x 73 453k Table 4-la W12x50 ¢Pn =657k >598k HSS 9x9x2(67.82 1b/ft) 585 k 5 39k 8 HSS 9x9 x— (67.82 Ib/f) T, 1 8 — 264 HSS 10 x10x —(62.46 Ib/ft) 583k : 388 k r, 2 HSS 10x10x—(62.46 Ib/f) B 3 & HSS 12 x12x>((58.10 Ib/ft) 596 k 397k ) L 0.65(25 8 HSS 12x12x~{(58.10 Ib/ (L), equlv=( )x _ 065 ) _6.16f 3 ] S - HSS 14 x14 x — (68.31 Ib/ft) 721k 3 480 k - 8 HSS 14 x14 x = (68.31 Ib/ft) r, HSS12.75%0.50(65.48 Ib/f) 645 k 8 W12x50 (Z, ).v =6.16'——¢F, =592k <598k NG [HSS16.00x0.312|(52.32 Ib/ft) sesk H5514.00x0.375(34.62 Ib/f) 275t 76 T - 2 HSS 18.00% 0.375(70.66 1b/ft) 715k [HSS1600x0312)(52.32 Ib/f) Try W12x53 ==2.11 7, =523m A4A=156m HSS 18.00 % 0.375(70.66 Ib/ft) 516k > y - =248in (b) LRED AsD ¥ P, =1.2(75)+1.6(220) = 442 k P, =75+220=295k ) L 0.65(25 L =KL=0.65(16)=10.40 ft L, =KL =065(16)=1040ft (L,), equiv = (L), = (25) =7.70 ft n 2.11 B y Size ¢P. Size Q y WSx 48 187 k W8x48 324k 451k W10x45 300k W X 5 — 5 | WI10x45 |Use W12x53 ¢P, =634k >598k| OK e wor | Wit et Alternate Solution W14x48 464k W14 48 ;gz : HP10x 4] 458k [HP10x 42 (L), 0.65(25)(12) S A = =37.28 HP12x53 606 k HP12x353 403k - 5. 1 295k ¢F;, =40.64 ksi Fv =50 ksi 1 536 k 1 357k ’ HSS 8x8x - (48.85 Ib/ft) H558x8><5(48-85 Ib/ft) ¢P = ¢F,,Ag =40.64(15.6)=634k - 1k HEQ Qv Qv 3747 70 Thif 484k HSS 9x9x > (42.79 b/f) A eew— . W
(©) 5 540 k 5 350k HSS12x12 x— (48.86 1b/ft) HSS12x12 x— (48.86 1b/ft) HSS 8.625 % 0.500 (43.43 1b/ft) 467 k HSS 8.625x0.500 (43.43 1b/ft) 311k HSS 9.625x0.500 (48.77 1b/ft) 541 k HSS 9.625x0.500 (48.77 1b/ft) 360 k HSS 10.00 % 0.500 (50.78 Ib/ft) 566 k HSS 10.00 % 0.500 (50.78 Ib/ft) 377k |[HSS10.75x0.375|(41.59 1b/ft) 472k |HSS10.75x0.375| (41.59 1b/ft) 314k LRFD ASD P =1.2(100)+1.6(200) = 440 k P, =100+200=300k L =KL=0.825)=20ft L =KL=08(25)=20ft £, Size ¢F, Size Q W8 (None work) W8 (None work) W10 x 68 478k W10x68 318k sg2k [W12x65 360k W14 x 68 440k WI14x74 320k HP12 <63 498 k HP12x63 332k HP14x73 681k HP14x73 453k 461k 5 HSS 8x 8%~ (59.32 Ib/ft) HSS 8 x 8% = (59.32 Ib/ft) 8 8 307k HSS 9% 9% — (55.66 Ib/ft) HSS 9% 9% (55.66 Ib/ft) 2 483k 2 322k HSS 10 10x§ (47.90 Ib/ft) 452k |HSS10x10 x% (47.90 Ib/ft) 300k 5 HSS12x12x % (48.86 Ib/ft) 492k HSS12x12 “Te (48.86 1b/ft) 327k HSS 10.00 % 0.625 (62.64 Ib/ft) 531k HSS10.00x0.625 (62.64 1b/ft) 353k HSS10.75x0.500 (54.79 1b/ft) 491k HSS10.75x0.500 (54.79 Ib/ft) 327k HSS12.75x0.375 (49.61 1b/ft) 400k HSS12.75x0.375 (49.61 Ib/ft) 327k HSS14.00x0.312|(45.65 1b/ft) 470 k HSS 14.00 x 0.312| (45.65) 313k HSS 16.00%0.312 (52.32 Ib/fr) 565 k HSS16.00x0.312 (52.32 Ib/ft) 376 k