‘short’  yield ‘in between’  inelastic buckling ‘long’  elastic buckling

Match these descriptions of column ‘slenderness’ and behavior:‘short’, ‘long’, ‘in between’inelastic buckling, elastic buckling, and yield ‘short’  yield‘in between’  inelastic buckling‘long’  elastic buckling COLUMNS 200

Name the three strength limit states for compression members (columns). Yield of the gross cross section, global buckling, local buckling COLUMNS 100

‘True’ column capacity does not match theoretical capacity based on Euler buckling and yielding. Identify two reasons for this. Reduced effective modulus due to inelastic behavior, residual stress, end restraint, initial crookedness, accidental eccentricity of load COLUMNS 300

USE AISC MANUAL Find the lightest A992 W14 for a 12’-0” column with a factored design load of Pu=2200 kips. Assume Ky=1.0 and Kx=2.0. AISC Table 4-1 KyL = 12’  try W14x193fPn=2330 kipsrx/ry = 1.60  KxL/(rx/ry) = 15’W14x193 still works and is lightest! fPn=2210 kips COLUMNS 400

What effect will modification of GA and/or GB to account for inelastic buckling have on the effective length, and why? The modification will decrease the effective length; consideration of inelastic buckling reduces G, increasing joint rigidity relative to the column, and therefore reducing effective length COLUMNS 500

For local buckling, we are concerned with ‘stiffened’ and ‘unstiffened’ elements. Define these terms. Stiffened – supported along 2 edges parallel to direction of compressive stressUnstiffened – supported along 1 edge but free on the other edge WILD CARD 100

Uneven cooling during hot rolling of structural shapes can result in this. Residual stress WILD CARD 200

USE AISC MANUAL In terms of E and Fy , what is the width-thickness limit, lr, for local buckling of the web of a W-shape in axial compression? lr = 1.49 √(E/Fy)Table B4.1a (Case 5) WILD CARD 300

When does AISC recommend that we ‘balance the welds’ and what does this mean? Cyclically-loaded axial members;configuring the weld group so that the c.g. of the weld group coincides with the c.g. of the member WILD CARD 400

Compression members with slender elements that are in the range of KL/r > 4.71√(E/QFy) have the same critical stress, Fcr, for design as compression members in that range w/o slender elements. Why? In that range of ‘slenderness’, global buckling will govern over local buckling WILD CARD 500

E60XX and E70XX are both matching weld metals for what ASTM steel? ASTM A36(≤3/4” thick, AISC J2.6) WELDS 100

What is the minimum length of weld for this end connection of flat-bar tension members with longitudinal welds only? W L Lmin=wAISC J2.2b WELDS 300

USE AISC MANUAL What is minimum size, ‘w’, for the fillet weld for this lap splice, and what is the reason for this limitation? PL ¼ x 10” PL ½ x 6” AISC Table J2.4 wmin = 1/8”A minimum size limitation is placed to prevent “too rapid” cooling of the weld. WELDS 200

For which limit states will the length of the weld, L, affect the capacity of this connection of a WT to a gusset plate? L Weld fractureBase metal – shear yieldBase metal – shear ruptureNet area fracture of the WTBlock shear of gusset plate or WT WELDS 500

SMAW SAW Submerged Arc Welds are more convex than Shielded Metal Arc Welds, and effective throat measures from root to face of weld (J2.2a); however, in practice, the same te is typically used. Is the effective throat thickness, te, for a SMAW the same as for a SAW? If no, why the difference? Note: this is “bonus” information, as it was not emphasized in lecture. WELDS 400

‘short’  yield ‘in between’  inelastic buckling ‘long’  elastic buckling