AISC Design Aids for Bending (Long Version) CE311
RECALL: PREVIOUS CLASS W21x48 Flange Web
RECALL: PREVIOUS CLASS W21x48 Flange lp = 9.15 l = 9.47 lr = 24.1 Web lp = 90.55 l = 53.6
RECALL: PREVIOUS CLASS W21x48 Flange lp = 9.15 l = 9.47 lr = 24.1 Web lp = 90.55 l = 53.6
RECALL: PREVIOUS CLASS W21x48 Flange lp = 9.15 l = 9.47 lr = 24.1 Web lp = 90.55 l = 53.6
RECALL: PREVIOUS CLASS W21x48 Flange lp = 9.15 l = 9.47 lr = 24.1 Web lp = 90.55 l = 53.6
RECALL: PREVIOUS CLASS W21x48 Flange lp = 9.15 l = 9.47 lr = 24.1 Web lp = 90.55 l = 53.6
RECALL: PREVIOUS CLASS W21x48 Flange lp = 9.15 l = 9.47 lr = 24.1 Web lp = 90.55 l = 53.6
RECALL: PREVIOUS CLASS W21x48 Flange lp = 9.15 l = 9.47 lr = 24.1 Web lp = 90.55 l = 53.6
RECALL: PREVIOUS CLASS W21x48 Flange lp = 9.15 l = 9.47 lr = 24.1 NON-COMPACT Web lp = 90.55 l = 53.6 COMPACT Web
RECALL: PREVIOUS CLASS W21x48 Flange lp = 9.15 l = 9.47 lr = 24.1 NON-COMPACT Web lp = 90.55 l = 53.6 COMPACT Web Interpolation: Mp = FyZ = 5350 in-kip at lp = 9.15 Mn = 5305 in-kip at l = 9.47 Mr = 0.7FyS = 3255 in-kip at lr = 24.1
RECALL: PREVIOUS CLASS W21x48 Flange lp = 9.15 l = 9.47 lr = 24.1 NON-COMPACT Web lp = 90.55 l = 53.6 COMPACT Web Interpolation: Mp = FyZ = 5350 in-kip at lp = 9.15 Mn = 5305 in-kip at l = 9.47 Mr = 0.7FyS = 3255 in-kip at lr = 24.1
RECALL: PREVIOUS CLASS W21x48 Flange lp = 9.15 l = 9.47 lr = 24.1 NON-COMPACT Web lp = 90.55 l = 53.6 COMPACT Web Interpolation: Mp = FyZ = 5350 in-kip at lp = 9.15 Mn = 5305 in-kip at l = 9.47 Mr = 0.7FyS = 3255 in-kip at lr = 24.1
RECALL: PREVIOUS CLASS W21x48 Flange lp = 9.15 l = 9.47 lr = 24.1 NON-COMPACT Web lp = 90.55 l = 53.6 COMPACT Web Interpolation: Mp = FyZ = 5350 in-kip = 445.8 kip-ft Mn = 5305 in-kip = 442.1 kip-ft
RECALL: PREVIOUS CLASS W21x48 Flange lp = 9.15 l = 9.47 lr = 24.1 NON-COMPACT Web lp = 90.55 l = 53.6 COMPACT Web Interpolation: Mp = FyZ = 5350 in-kip = 445.8 kip-ft => Mp/W = 267 kip-ft Mn = 5305 in-kip = 442.1 kip-ft => Mn/W = 265 kip-ft
RECALL: PREVIOUS CLASS W21x48 Flange lp = 9.15 l = 9.47 lr = 24.1 NON-COMPACT Web lp = 90.55 l = 53.6 COMPACT Web Interpolation: Mp = FyZ = 5350 in-kip = 445.8 kip-ft => Mp/W = 267 kip-ft Mn = 5305 in-kip = 442.1 kip-ft => Mn/W = 265 kip-ft
RECALL: PREVIOUS CLASS W21x48 Flange lp = 9.15 l = 9.47 lr = 24.1 NON-COMPACT Web lp = 90.55 l = 53.6 COMPACT Web Interpolation: Mp = FyZ = 5350 in-kip = 445.8 kip-ft => Mp/W = 267 kip-ft Mn = 5305 in-kip = 442.1 kip-ft => Mn/W = 265 kip-ft HOLY $#@%! The Z-table Mp/W accounts for Local Buckling!!!
A Business Idea for this Class
Produce Charts: “e.g.; Mapp = 280 ft-kips, Lb = 15’
Produce Charts: “e.g.; Mapp = 280 ft-kips, Lb = 15’
Produce Charts: “e.g.; Mapp = 280 ft-kips, Lb = 15’
Produce Charts: “e.g.; Mapp = 280 ft-kips, Lb = 15’
e.g.#1: LTB Charts – pp. 3-96 Given: Pick lightest A992 W Mapp = 310 ft-kips Lb = 20 feet
e.g.#1: LTB Charts – pp. 3-96 to Given: Pick lightest A992 W Mapp = 310 ft-kips Lb = 20 feet
e.g.#1: LTB Charts – pp. 3-99 to 3-142 (Fy= ??) Given: Pick lightest A992 W Mapp = 310 ft-kips Lb = 20 feet Cb = 1 (constant end-moments)
e.g.#1: LTB Charts – pp. 3-99 to 3-142 (Fy= ??) Given: Pick lightest A992 W Mapp = 310 ft-kips Lb = 20 feet Cb = 1 (constant end-moments)
e.g.#1: LTB Charts – pp. 3-96 to Given: Pick lightest A992 W Yo! P. 3-122 Mapp = 310 ft-kips, Lb = 20 feet Given: Pick lightest A992 W Mapp = 310 ft-kips Lb = 20 feet
e.g.#1: LTB Charts – pp. 3-96 to Given: Pick lightest A992 W Mapp = 310 ft-kips, Lb = 20 feet Given: Pick lightest A992 W Mapp = 310 ft-kips Lb = 20 feet
e.g.#1: LTB Charts – pp. 3-96 to Given: Pick lightest A992 W Mapp = 310 ft-kips, Lb = 20 feet Given: Pick lightest A992 W Mapp = 310 ft-kips Lb = 20 feet
e.g.#1: LTB Charts – pp. 3-96 to Given: Pick lightest A992 W Mapp = 310 ft-kips, Lb = 20 feet Given: Pick lightest A992 W Mapp = 310 ft-kips Lb = 20 feet W18x76
e.g.2: Pick a Shape (Worry about Self Wt. at the end) Given: A992 Papp = 40kips 18 feet
Handy Cb Chart
Handy Cb Chart
W16x45
W16x40?
W16x40: LTB: Mn/W = 159 (1.67) = 266 kip-ft But… Mp/W = 182.5 kip-ft So… LTB will not occur Mn/W = 182.5 kip-ft
Now, Check Self-Weight Msw = (0.040)(182)/8 = 1.62 kip-ft So, the total applied moment is M = 180 + 1.62 kip-ft = 181.6 kip-ft While, Mn/W = 182.5 kip-ft So, W16x40 works.
Awesome Design Aids and Limitations 1. Plastic 2.
Awesome Design Aids and Limitations The LTB Charts 1. Plastic 2. LTB 3. Flange Local Buckling
Awesome Design Aids and Limitations The LTB Charts Plastic, LTB, and Local Buckling are considered Limitations: 1. Plastic 2. LTB 3. Flange Local Buckling
Awesome Design Aids and Limitations The LTB Charts Plastic, LTB, and Local Buckling are considered Limitations: Fy = 50 ksi W and C shapes 1. Plastic 2. LTB 3. Flange Local Buckling
Awesome Design Aids and Limitations 1. Plastic 2. LTB 3. Flange Local Buckling
Awesome Design Aids and Limitations The Z Tables 1. Plastic 2. LTB 3. Flange Local Buckling
Awesome Design Aids and Limitations The Z Tables Plastic and Local Buckling are considered Limitations: 1. Plastic 2. LTB 3. Flange Local Buckling
Awesome Design Aids and Limitations The Z Tables Plastic and Local Buckling are considered Limitations: Fy = 50 ksi W and C shapes 1. Plastic 2. LTB 3. Flange Local Buckling
Awesome Design Aids and Limitations The Uniform Load Tables 1. Plastic 2. LTB 3. Flange Local Buckling
Awesome Design Aids and Limitations The Uniform Load Tables Plastic and Local Buckling are considered 1. Plastic 2. LTB 3. Flange Local Buckling
Awesome Design Aids and Limitations The Uniform Load Tables Plastic and Local Buckling are considered They automatically include beam self-weight! 1. Plastic 2. LTB 3. Flange Local Buckling
Awesome Design Aids and Limitations The Uniform Load Tables Plastic and Local Buckling are considered They automatically include beam self-weight! Limitations: 1. Plastic 2. LTB 3. Flange Local Buckling
Awesome Design Aids and Limitations The Uniform Load Tables Plastic and Local Buckling are considered They automatically include beam self-weight! Limitations: Uniform Loads Fy = 50 ksi W and C shapes Simply-Supported 1. Plastic 2. LTB 3. Flange Local Buckling
Handling “Word Problems” & Getting the Fast Answer 1. Plastic 2. LTB 3. Flange Local Buckling
Handling “Word Problems” & Getting the Fast Answer “Select a continuously supported W beam for a uniform load” 1. Plastic 2. LTB 3. Flange Local Buckling
Handling “Word Problems” & Getting the Fast Answer “Select a continuously supported W beam for a uniform load” Fast: Z-tables Really Fast: Uniform Load Tables LTB Chart? Meh. Lb=0, so you could find that position on the chart, but that’s like finding a needle in a stack of needles 1. Plastic 2. LTB 3. Flange Local Buckling
Handling “Word Problems” & Getting the Fast Answer “Select a continuously supported W beam for a point load” 1. Plastic 2. LTB 3. Flange Local Buckling
Handling “Word Problems” & Getting the Fast Answer “Select a continuously supported W beam for a point load” Fast: Z-tables Faster: LTB Chart Really Fast: Uniform Load Tables 1. Plastic 2. LTB 3. Flange Local Buckling
Handling “Word Problems” & Getting the Fast Answer “Select a W beam for a point load with Lb = 12 feet” 1. Plastic 2. LTB 3. Flange Local Buckling
Handling “Word Problems” & Getting the Fast Answer “Select a W beam for a point load with Lb = 12 feet” ~ Slow: Z-tables Faster: LTB Chart Really Fast: Uniform Load Tables 1. Plastic 2. LTB 3. Flange Local Buckling
Handling “Word Problems” & Getting the Fast Answer “Compute the allowable capacity of a built-up beam with Lb = 12 feet” 1. Plastic 2. LTB 3. Flange Local Buckling
Handling “Word Problems” & Getting the Fast Answer “Compute the allowable capacity of a built-up beam with Lb = 12 feet” Strictly hand-calcs 1. Plastic 2. LTB 3. Flange Local Buckling