STRUCTURAL SYMBOLS – I
Structural drawings should reflect the rigid line control for the produced drawing. Structural drawing technique refers to a style or quality of a drawing imparted by the individual drafter to the work. It is characterized by crisp black line work, lettering, consistency, and uniformity.
The development of good detail drawings is a real engineering accomplishment and art. Students should develop a stylized drawing technique that conforms to the rigid conventions of line drafting with added variations of artistic techniques to produce a very individualized finished drawing.
Lettering
Lettering heights will be in accordance with the commendations of the ANSI Standards. General lettering and dimensioning use 3/32″.
Drawing Numbers
All drawings will be numbered using the standard description for structural drawings. All drawings are numbered repeatedly with the related drawing letters preceding the number as like
S- Structural steel (S-1, S-2, S-3, etc.).
R – RCC (R-1, R-2, R-3, etc.).
X – Fabrication (X-1, X-2, X-3, etc.).
A – Architecture (A-1, A-2, A-3, etc.).
Drawing number should receive the greatest emphasis and have a height greater then 1/4”.
Drawing Scales
The standard unit of structural measurement is “FEET”. The scale is always noted as FEET and INCHES. Such as 1/8″ = 1′ -0” or 1/4″ = 1′ – 0″. The word SCALE is always written to identify what is being read, for example: SCALE: 1/8″ = 1′ -0″.
Any scale specified on an “Architect’s Scale” can be used on structural drawings. Generally plan views and elevations are drawing using a scale of 1/8″ = 1′ -0″ or 1/4″ = 1′ – 0″. Connection details use scales of
1″ = 1′ – 0″, 1 1/2″ = 1′ -0″ or 3″ = 1′ – 0″ for smaller details. Shop drawings use a scale of 1″ = 1′ – 0″ for beams 21″ or less and a scale of 3/4″ – 1′- 0″ for beams greater than 21″.
Titles
All entities on a drawing must have a title whether it is a elevation, symbols legend, section, plan view, detail, note column, etc. Titles should be lettered catchy to viewer’s eye. Normally the lettering is between 1/4″ and 3/8″ high. To intonation the titles even more they are underlined. Underlining can consist of a single line, a double line, or a combination of thick and thin lines. The underlining can be centered with the lettering, be flush, or be broken as shown when using circle call‑outs. A few examples of titles and underlining are shown below.
Section Marks
Section marks are used to indicate where sections are being taken or cut. Structural drafting practices are very similar to that used in engineering drawing. Because of the complexity of structural drawings cutting plane lines are generally omitted and only the arrow indicating the direction of sight of the section view is shown. The section call‑out consists of a 1/2″ diameter circle, an arrow indication the direction of sight, and two numbers. The upper number/letter indicates the name of the section on the sheet and the lower number refers to the sheet where the section view is drawn.
The lettering in the section call‑out circle is always horizontal regardless of the direction of the arrow. The arrow is a 45 degree line, tangent to the circle.
The arrow can be left open or colored in. The short line segments extending from the circle represent the cutting plane line. They can be single lines, double lines, or alternating thick and thin lines to conform to the overall drawing style.
