CSTM 201_QUIZ 4 STEEL STUDY GUIDE

Iron-carbon alloy/steel is priced by the ___ and detailed by the ___

ton, piece

What is steel?

Any of various iron-based alloys with less carbon than cast iron and more than wrought iron. Its strength, hardness, and elasticity vary with composition and heat treatment. It combines high strength and stiffness with elasticity, and is likely the strongest low-cost structural material available, by weight.

Benefits of steel:

Benefits:

Reduced construction time and building in all seasons

Large spans and bay sizes, so more flexibility for owners

Easier to modify and reinforce later

Relatively lightweight which can reduce foundation costs, durable, long-lasting, and recyclable

Steel is fabricated___

off-site

On-site erection is ___, which gives scheduling___

rapid, advantages

What are 2 disadvantages of steel?

Corrosion and loss of strength when heated in a fire

MasterFormat: Steel is in which division?

Division 05

STEEL CONTENT: CARBON CONTENT AND ALLOYS.

Mild and soft steel contain ___% carbon content

0.15-0.25

STEEL CONTENT: CARBON CONTENT AND ALLOYS.

Medium steel contains ___% carbon content and is ____; ASTM A36 (0.25–0.29%), yield 36,000 psi

0.25-0.45, most structural steel

STEEL CONTENT: CARBON CONTENT AND ALLOYS

Hard steel contains ___% carbon content

0.45-0.85

STEEL CONTENT: CARBON CONTENT AND ALLOYS

Spring steel contains ___% carbon content

0.85-1.8

STEEL CONTENT: CARBON CONTENT AND ALLOYS

What is carbon steel?

it is an unalloyed steel; other (residual) elements are kept below set limits rather than added on purpose

STEEL CONTENT: CARBON CONTENT AND ALLOYS

What is alloy steel?

Carbon steel with elements such as chromium, nickel, or molybdenum added deliberately for specific properties

STEEL CONTENT: CARBON CONTENT AND ALLOYS

What is HSLA steel?

One example is ASTM A572 which yields ____psi

High-strength low-alloy steel: engineered for higher strength, ductility, and corrosion resistance

50,000

STEEL CONTENT: CARBON CONTENT AND ALLOYS

More carbon means ___, but ____

more strength and hardness, less ductility and weldability

STEEL SHAPES:

What shape is this?

What is it used for?

W or WF (wide flange)

The most structurally efficient beam and column shape

STEEL SHAPES:

What shape is this?

What is it used for?

S (american standard beam)

Beams

STEEL SHAPES:

What shape is this?

What is it used for?

HP (high piles)

Transferring load from structure to foundation deep in the ground

STEEL SHAPES:

What shape is this?

What is it used for?

C (american standard channel)

Truss members, bracing, short-span beams, lintels

STEEL SHAPES:

What shape is this?

What is it used for?

L (angle)

Short beams, small loads, edge supports, floor openings, lintels, bracing, connectors

STEEL SHAPES:

What shape is this?

What is it used for?

HSS (hollow structural section)

Columns, bracing, exposed structure

STEEL SHAPES:

What shape is this?

What is it used for?

WT - Structural tee cut from a W shape

Chords, connections, miscellaneous steel

READING STEEL LABELS:

First number =

Second number =

Common fy =

Nominal depth in inches

Weight in lbs/ft

50 ksi

READING STEEL LABELS:

First number =

Second number =

Common fy =

Nominal depth in inches

Weight in lbs/ft

36 ksi

READING STEEL LABELS:

First number =

Second number =

Third number =

Common fy =

Leg 1 in inches

Leg 2 in inches

Thickness in inches

36 ksi

READING STEEL LABELS:

First number =

Second number =

Third number =

Common fy =

Side 1 in inches

Side 2 in inches

Wall thickness in inches

46 ksi

READING STEEL LABELS

First number =

Second number =

Common fy =

Outside diameter in inches

Wall thickness in inches

42 ksi

Nominal means:

approximate. Each nominal measurement is not the exact measurement of a cut.

OPEN WEB JOISTS:

What are these arrows pointing at?

What does it do?

The open web joist which allows mechanical services to pass through

OPEN WEB JOISTS:

The ceiling can be attached to the ___ chords, suspended below them for more service space, or left off to ___ the joists and deck

bottom, expose

OPEN WEB JOISTS:

Fire-resistance rating depends on the rating of the ___ and ___ assembly.

floor, ceiling

OPEN WEB JOISTS

Joists bear on ___ or ___ concrete ___, or on steel beams or joist girders (heavier versions of open-web joists).

masonry or reinforced, bearing walls

DECK TYPES: Form decking

What it does

Typical depths and spans

Permanent formwork for a reinforced concrete slab until the slab can carry itself and its live load

9/16 in. for 1′-6″ to 3′;

1 in. for 3′ to 5′;

2 in. for 5′ to 12

DECK TYPES: Composite decking

What it does

Typical depths and spans

Acts as tensile reinforcement for the slab, bonded by embossed ribs; shear studs welded through the deck to the beam give composite action

1-1/2 in. for 4′ to 8′;

2 in. for 8′ to 12′;

3 in. for 8′ to 15′

DECK TYPES: Cellular decking

What it does

Typical depths and spans

Corrugated sheet welded to a flat sheet, forming raceways for electrical and communications wiring; can serve as an acoustic ceiling

1-1/2 and 2 in. for 6′ to 12′;

3 in. for 10′ to 16′

DECK TYPES: Masterformat group:

05 30 00

RED =

PURPLE =

GREEN =

BLUE =

YELLOW =

ORANGE =

Girder

Diagonal bracing

Beam

Column

Shear wall

Moment-resisting frame

PARTS AND THEIR ROLES: Column

Carries load down to the foundation; sits on a regular structural grid

PARTS AND THEIR ROLES: Girder

Spans column to column

PARTS AND THEIR ROLES: Beam

Frames into girders

PARTS AND THEIR ROLES: Connections

Use transitional elements (angles, tees, plates); often bolted or welded

PARTS AND THEIR ROLES: Bearing plate

Spread a column or beam load where steel bears on concrete or masonry

PARTS AND THEIR ROLES: Plate girder

Built up from plates or shapes. Cover plates on the flanges increase section modulus; stiffeners

resist web buckling

LATERAL SYSTEMS: Shear wall

How it resists wind and earthquake load

A solid wall panel resists lateral load (wind, earthquake, soil pressure) in its own plane

LATERAL SYSTEMS: Moment-resisting frame

How it resists wind and earthquake load

Rigid beam-to-column connections resist sway through bending

LATERAL SYSTEMS: Diagonal bracing

Braces triangulate the bay and carry load in tension or compression

STEEL ERECTION

• The AISC Code of Standard Practice holds the ____

responsible for the means, methods, and safety of erection

• A qualified ____ inspects and rigs every load

• Connectors install at least ___ bolts per connection while

hoisting; the rest go in after the frame is plumbed

• Multiple-lift rigging reduces the number of ___ lifts

erector

rigger

two

crane

CHRISTMAS TREEING

• Maximum of ___ pieces

• Pieces must be of similar ___

• Decking ____ are prohibited

• Workers must be ____ in the procedure

• The assembly must be professionally ____

• The crane ____ must allow it

5

type

bundles

trained

engineered

manufacturer

TEMPORARY BRACING

goes in before the frame is plumbed and keeps it stable until the permanent lateral system

is in place. In a braced frame it comes out after final bolt-up. OSHA limits unfinished bolting or welding to ___

floors or ___ft above the last permanently secured floor.

four, 48

CONNECTIONS: BOLTING AND WELDING: Type 1: rigid frame (moment)

What is its behavior?

Lateral stability?

Holds its original angle under load; transfers moment and shear

The frame itself provides it

CONNECTIONS: BOLTING AND WELDING: Type 2: simple frame (shear)

What is its behavior?

Lateral stability?

Resists only shear; free to rotate under gravity load

Needs shear walls or diagonal bracing

BOLTS:

A325 and A490

high-strength bolts, 1/2 to 1-1/2 in. diameter; most common sizes 3/4, 7/8, and 1 in.

BOLTS:

Bearing joint

load transfers by bearing on the bolts.

BOLTS:

Slip-critical joint

load transfers by friction in the joint

BOLTS:

Shear plane

where the connected pieces try to slide past each other. A bolt carries more with its threads excluded from the shear plane, but the most common bolt (A325, 3/4 in.) is usually installed with threads included.

BOLTS:

Snug-tight

a few impact-wrench hits or an ironworker’s full effort on a spud wrench

BOLTS:

Pretensioned

a calibrated wrench tightens to a specified tension

BOLTS:

Stick-out

positive or zero is acceptable; negative is not

WELDS:

Weld symbols

On fabrication and erection drawings give the weld type, size, length, and spacing.

Basic types: fillet, groove (butt), plug, and slot.

WELDS:

Bolting vs welding

Bolting is generally faster and has no weather restrictions

Welding can make a joint stronger than the base metal but is weather-sensitive, especially in the field.

WELDS:

Weld size

Must match the drawings. Fillet welds up to and including 5/16 in. are usually single-pass; larger fillets and bevel groove welds need multiple passes

FIRE, CORROSION, AND SPECIALTY STEELS: FIRE

Steel is incombustible, but it softens and loses strength above about ___°F

• Building fires are not hot enough to melt steel, but they can weaken it enough to ___

• Fire-resistive construction requires steel to be ____, _____or ____

• Taller buildings (the lecture uses “over three stories”) need the ____

protected long enough for everyone to get out

1,000

Fail

Coated, covered, enclosed

Frame

FIRE, CORROSION, AND SPECIALTY STEELS: CORROSION

• Unprotected steel ___ (oxidizes)

• It must be ___,___, or ____

Corrodes

Painted, galvanized, chemically treated

Which fire protective coating is this?

How does it work?

Concrete encasement

Fully surrounds a column or beam

Which fire protective coating is this?

How does it work?

Enclosure board

Build a fire-resistive box around the member

Which fire protective coating is this?

How does it work?

Metal lath + plaster

Build a fire-resistive box around the member

Which fire protective coating is this?

How does it work?

Spray on

Coats exposed members

Which fire protective coating is this?

How does it work?

Sheet metal enclosed + loose fill insulation

Slows heat transfer to steel

Which fire protective coating is this?

How does it work?

Water

Slows heat transfer to steel

SPECIALTY STEEL: Stainless steel

Key property?

Typical use?

12% or more chromium; highly corrosion-resistant

Exposed, corrosion-prone applications

SPECIALTY STEEL: Weathering steel

Key property?

Typical use?

Forms a protective, adherent oxide coating in weather, so painting is not needed against most atmospheric corrosion

Exposed structures where painting is undesirable

SPECIALTY STEEL: Tungsten steel

Key property?

Typical use?

10–20% tungsten; hardness and heat retention

High-temperature tooling and components

LIGHT GAUGE METAL STUD FRAMING

• Common in ___ l work because metal is ___,

which reduces the amount of combustible material in the

building

• Studs stay straight: they do not ___ or ____

• Used for ___,___,___ and other ____

• Wood studs cost ___ as material; which is cheaper overall is

debated

• Parts include top and bottom plates, common, jamb, and jack

studs, lintels, trimmers, and nogging

commercial, noncombustible

warp, rot

walls, ceilings, soffits, interior framing

less

1:

2:

3:

4:

5:

6:

7:

8:

9:

10:

11:

12:

Top plate, diagonal brace, jack stud, lintel, head trimmer, bottom plate, common stud, jamb stud, secondary jam stud, still trimmer, jack stud, nogging