Structural Steel

Question 1

Analysis and design process aims

Answer 1

The analysis process is aimed at establishing the demand, and the design process is aimed at ensuring
sufficient capacity.

Question 2

Elastic Modulus E

Answer 2

= 200 GPa
= 200 kN/m2
* 1000 N/mm2 = MPa

Question 3

At ultimate stain how much elongation is there

Answer 3

22% - grade 300 steel

Question 4

Plate thickness on yeild stress

Answer 4

Thinner plate sections = higher yeild stress

Question 5

Nominal section moment capacity Ms

Answer 5

largest moment that the section can resist

Ms = Zeff * fy

Question 6

Plastic limit Yep

Answer 6

Slenderness limit such that the section can reach full plasticity before buckling occurs

Question 7

Yield limit Yey

Answer 7

Slenderness limit that the section can reach yield stress before buckling.

Question 8

Section Capacity

Answer 8

strength of a very small length of a member / maximum capacity of the structural section.

Question 9

Member Capacity

Answer 9

strength of the member / strength of the beam allowing for its length and lateral restraint conditions

Question 10

Critical flange

Answer 10

The flange which would deflect the furthest laterally during buckling. Typically this is the compression flange, however in the case of a cantilever beam it is the tension flange.

Question 11

what does member moment capacity depend on?

Answer 11

• cross section properties
• bending moment pattern
• degree of restraint
• effective length
• load height

Question 12

why are restraints classified as full partial or lateral

Answer 12

based on how well they restrain the critical flange against lateral movement, and the whole cross- section against twisting.

Question 13

What does effective length for a beam depend on?

Answer 13

• Lateral-torsional (twist) restraint
• y-axis rotational restraint (warping) - - load height relative to the shear centre.

Question 14

Why are steel beams more venerable to having issues with vibration

Answer 14

The beams have much longer spans than timber beams and are much lighter than concrete beams

Question 15

What variables govern deflection?

Answer 15

• Span (L) of the member
• Load – point load (W kN), or udl (w kN/m)
• Elastic Modulus of the material (E)
• Second Moment of Inertia or Bending Stiffness (I)

Question 16

why is it important to understand joint conditions?

Answer 16

• Global stability of the structure
• How the structure will deform
• The distribution and type of force demand on the structural elements
• The demands on the joints/connections.

Question 17

bolt types

Answer 17

• structural bolts
• fully tensioned bolts

Question 18

weld types

Answer 18

• fillet weld (cheap, weak, bad for fatigue)
• incomplete penetration butt weld (weak, bad fatigue, no ductility)
• complete penetration butt weld (expenny, develops full strength of weakest member, best for fatigue)

Question 19

web side plate WP-NC

Answer 19

carries verticle loading, limited axail load capacity, faliure mode is web plate in-plane yeilding and bolt hole elongation, no design moment capacity

Question 20

flexible end plate FE-NC

Answer 20

carries verticle loading, faliure mode is end out of plane bending, reasonable compression capacity, no design moment capacity

Question 21

column end plates

Answer 21

depending on number of bolts will be a pinned or fixed connection

Question 22

gusset plate connection

Answer 22

for diagonal member

• Transfers axial force in gusset into vertical and horizontal forces in beam and column
• Typically designed so the effective centrelines of the brace force meets the intersection of the beam and column centreline

Question 23

bolted moment end plate

Answer 23

• Connection can be designed to be weaker or stronger than the beam
• Failure mode is by endplate and or column flange out of plane bending
• Bolt or weld failure suppressed
• Complex load paths and design procedure

Question 24

bolted moment resisting splice

Answer 24

to connect 2 beams

• Flanges resist moment-induced and direct axial forces
• Web resists shear and moment due to eccentric shear transfer
• Bolt and weld failure suppressed

Question 25

column splice

Answer 25

* Flanges resist moment-induced and direct axial forces * Web resists shear and moment due to eccentric shear transfer * Bolt and weld failure suppressed * Compression forces can be resisted by end bearing

Question 26

steel to concrete wall connection

Answer 26

typically primary/secondary beam to weld plate connection

Question 27

Compact Ys

Answer 27

Section able to reach and sustain fully plastic moment Mp without local buckling.

Question 28

Non-Compact Yep

Answer 28

Local buckling starts after yielding but before fully plastic moment is achieved. Moment capacity exceeds yeild limit My but is less than Mp.

Question 29

Slender Ys>Yey

Answer 29

Local buckling occurs before yield stress reached (elastic failure). Moment capacity less than yield moment My.