What carbon range is typical for steel?
About 0.1% to 1.7% carbon.
How does cast iron compare to steel?
Cast iron has about 2.5% to 4% carbon and is strong, hard, and brittle; steel has less carbon and is strong, semi-malleable, and ductile.
What is the difference between BOF and EAF steelmaking?
Basic oxygen furnace steel uses about 25% to 35% recycled steel plus virgin ore, while electric arc furnace steel uses about 90% to 100% recycled steel and is common for structural shapes and reinforcing bar.
Why is EAF steel considered more sustainable than BOF steel?
Its embodied energy is about one-half to one-third that of BOF steel because it uses much more recycled content.
What are common structural steel grades and yields from the slides?
A992 is 50 ksi yield and A36 is 36 ksi yield.
How are W-shapes designated?
By nominal depth in inches and weight per foot.
Which steel sections are commonly used for columns versus beams/girders?
Columns commonly use W-shapes or HSS; beams and girders commonly use W-shapes and sometimes open web steel joists for lighter floor/roof framing.
What is an advantage of open web steel joists over hot-rolled steel sections?
They weigh less for an equal span and can also make it easier to pass services through the open web.
What is the maximum span rule of thumb for steel joists?
The maximum span is about 24 times the joist depth.
What are the two main methods of force transfer in bolted shear connections?
Bearing connections transfer shear through the bolts, while slip-critical connections transfer shear through friction between contact surfaces.
What are the three column-to-beam connection types?
Rigid (moment) Type I, simple (shear) Type II, and semirigid Type III.
How can lateral stability be provided in a steel-framed building?
By moment connections, braced frames, rigid column bases, or tying the frame to shear walls such as stair/elevator cores.
What is the basic sequence of structural steel erection after foundations are ready?
Set columns on anchor rods/base plates, plumb up the frame with temporary bracing, perform final bolt-up/welds, install decking and shear studs, then place reinforced concrete slabs.
What are common fireproofing methods for steel?
Spray-applied fireproofing, gypsum board encasement, concrete encasement, intumescent paint, and rated suspended ceiling assemblies.
What is galvanic action?
Accelerated corrosion of the less noble metal when dissimilar metals are in contact in the presence of an electrolyte.
