Structural Components and Connections
Behavior and design of members and joints
Component questions test flexure, shear, axial compression and buckling, combined loading, development length, splices, bearing, bolts, welds, anchors, and connection limit states. For bolts, know shear, tension, bearing, and slip-critical behavior, plus thread condition. For welds, know fillet and groove types and effective throat. Eccentric connections require checking combined shear and tension, and prying action may govern. A connection is only as strong as its weakest limit state.
Traps
Thread condition matters: A325-N versus A325-X changes shear strength because threads may or may not lie in the shear plane. Check edge distance, bolt spacing, and bearing. For fillet welds, effective throat is 0.707 times the leg size. Do not confuse serviceability with strength. Also check block shear, tearout, and base-metal strength, not just bolt capacity.
Worked example: A 3/4-in A325-N bolt in single shear has Fnv = 54 ksi nominal and area 0.4418 in². Nominal shear = 54 × 0.4418 ≈ 23.9 kip. With φ = 0.75, design strength ≈ 17.9 kip. If threads are excluded from the shear plane, the applicable nominal stress is higher per code.
Rule of thumb: Fillet weld effective throat = 0.707 × weld leg size.