CD Drafter Structural & Mechanical Systems Flashcards

In structural drafting, what does a dashed line running along the center of a beam or column typically represent?

Answer: The centerline or neutral axis of the member

A centerline (long-short-long dash pattern) marks the axis of symmetry or center of structural members such as beams and columns.

What type of structural connection allows rotation between members but resists shear and axial loads?

Answer: Pin connection

A pin connection resists both shear and axial forces but allows rotation, making it a common idealized support in structural analysis.

On a mechanical assembly drawing, what does a balloon with a number inside, connected by a leader line, indicate?

Answer: A part number referencing the bill of materials

Balloons on assembly drawings identify individual parts by their item number, which corresponds to rows in the bill of materials.

A W8×31 designation on a structural drawing refers to:

Answer: A wide-flange I-beam with a nominal depth of 8 inches and weight of 31 lb/ft

Wide-flange (W-shape) designations use depth in inches × weight per linear foot, so W8×31 is 8 inches deep and weighs 31 lb/ft.

What is the function of a gusset plate in a structural steel connection?

Answer: To reinforce and transfer loads between connected members

Gusset plates are flat steel plates welded or bolted at joints to distribute and transfer loads between intersecting structural members.

In a piping or mechanical system drawing, what does a 'P&ID' stand for?

Answer: Piping and Instrumentation Diagram

A P&ID (Piping and Instrumentation Diagram) shows the piping, equipment, instruments, and control loops of a process system.