ETC Structural Analysis & Load Calculations Flashcards

What is allowable stress design (ASD) in structural engineering?

Answer: A design method that limits working stresses to a fraction of the material's yield or ultimate strength

ASD ensures that stresses under service loads do not exceed allowable values set well below the material's failure stress, providing an inherent safety margin.

In reinforced concrete design, what is the purpose of stirrups (shear ties)?

Answer: To resist diagonal tension forces and prevent shear-compression failure

Stirrups are closed or U-shaped transverse reinforcement bars that resist diagonal tension cracking caused by shear forces in concrete beams.

What does moment of inertia of a cross section govern in beam design?

Answer: The resistance of the cross section to bending and deflection

The moment of inertia measures how the cross-sectional area is distributed relative to its neutral axis, directly controlling bending stiffness and deflection.

What is the role of a transfer beam in a structural system?

Answer: To collect loads from columns or walls above and transfer them to fewer supporting elements below

Transfer beams redirect vertical loads from upper columns or load-bearing walls that cannot continue to the foundation, carrying those forces horizontally to other supports.

What is the purpose of a diaphragm in a building structural system?

Answer: To distribute lateral (wind or seismic) forces to vertical resistance elements like shear walls

A structural diaphragm (floor or roof deck) acts as a horizontal plate that gathers and distributes lateral forces to shear walls or moment frames.

What does structural redundancy mean in building design?

Answer: Having multiple load paths so that failure of one element does not cause total collapse

Structural redundancy provides alternative load paths so that if one member fails, forces redistribute to others, preventing progressive or disproportionate collapse.