Joint Design & Load Calculations Flashcards
7 cards from real CFS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Joint Design & Load Calculations flashcards as text
For a bolt group loaded in-plane by a force not through the centroid, the instantaneous center of rotation (ICR) method is used to:
Answer: Determine the critical bolt load by accounting for bolt deformation and rotation
The ICR method accounts for realistic bolt deformation patterns under eccentric loading to find the most critically loaded fastener in a group.
The 'proof load' of a fastener is best defined as:
Answer: The maximum load the fastener can withstand without permanent deformation
Proof load is the tensile force that a fastener must support without taking any permanent set (deformation), and it defines the upper limit for preload.
Which of the following best describes 'galling' failure in a fastener joint?
Answer: Adhesive wear and surface tearing between mating metal surfaces under high contact stress
Galling is a form of severe adhesive wear where metal transfers between mating surfaces (e.g., bolt and nut threads) under high contact pressure, often leading to seizure.
In a tension-critical structural connection (e.g., AISC), the design tension strength of a bolt is taken as a fraction of its ultimate tensile strength. What fraction does AISC LRFD use (φ)?
Answer: φ = 0.75
AISC LRFD uses a resistance factor φ = 0.75 for bolt tension, reflecting the greater variability and consequence of bolt tensile failure.
The 'prying action' in a bolted T-stub connection causes:
Answer: An amplification of bolt tension beyond the directly applied external load
Prying action occurs when a flexible fitting flexes and levers against the connecting surface, adding an additional prying force Q to the bolt tension beyond the direct load.
Minimum edge distance for a fastener hole is primarily specified to prevent:
Answer: Shear tearout (block shear) through the material edge
Minimum edge distance prevents the material from tearing out (shear tearout failure) between the fastener hole and the edge of the member under shear load.
In a welded-and-bolted combined joint, current AISC specifications for static loading generally require:
Answer: Welds to carry the entire load; bolts are ignored unless slip-critical
AISC does not allow load sharing between welds and snug-tight or pretensioned bolts in bearing because welds are stiffer and attract load first, so welds must carry the full load.