How to Read Structural Drawings ? | Q & A

Reading structural drawings is about understanding intent → translating it to site execution. Below is a step-by-step, site-oriented method interviewers expect fresh civil engineers to know.

1. Start with the Title Block (Never Skip This)

Check:

• Project name & drawing title

• Drawing number & revision (latest is critical)

• Scale

• Structural consultant name

• Applicable codes (IS 456, IS 13920, etc.)

Many site errors happen due to using old revisions.

2. Understand the Structural Layout / Grid

• Identify grid lines (A-B-C / 1-2-3)

• Note column locations with respect to grids

• Match grid dimensions with architectural drawings

Site use: Column marking and setting out.

3. Identify Different Drawing Types

Structural drawings are usually divided into:

• General Notes

• Foundation layout

• Column layout

• Beam layout

• Slab layout

• Section & detail drawings

• Bar Bending Schedule (BBS)

Never read one drawing in isolation.

4. Reading Column Drawings

Check:

• Column mark (C1, C2, etc.)

• Size (e.g., 300×450 mm)

• Reinforcement:

  • Number & diameter of main bars

  • Stirrups diameter and spacing

• Lap splice location

• Column schedule reference

Site tip: Always cross-check with column schedule.

5. Reading Beam Drawings

Check:

• Beam mark (B1, B2, etc.)

• Size (width × depth)

• Top and bottom reinforcement

• Extra bars near supports

• Stirrup spacing (closer at supports)

Rule of thumb:
More steel near supports = higher moment/shear.

6. Reading Slab Drawings

Check:

• Slab thickness

• Type (one-way / two-way)

• Main bars and distribution bars

• Bar spacing and diameter

• Cantilever slab reinforcement

• Slab panel marking

7. Understand Sections & Details (Very Important)

• Section drawings explain:

  • Reinforcement anchorage

  • Beam-column junctions

  • Staircase details

• Use sections when:

  • Drawing looks confusing

  • Execution is unclear

Sections clarify what plans cannot.

8. Read Notes, Symbols & Abbreviations

Common examples:

• Ø = Diameter

• @ = Spacing

• c/c = center to center

• T/B = Top/Bottom

• EF = Each Face

Never assume—read legend carefully.

9. Check Levels & Dimensions

• RL (Reduced Level)

• Plinth level

• Beam bottom & slab top levels

• Foundation depth

Levels control excavation and shuttering.

10. Bar Bending Schedule (BBS)

From BBS:

• Bar shape code

• Cutting length

• Quantity

• Weight

Site use: Steel ordering and bar cutting.

11. Cross-Check with Architectural Drawings

Always verify:

• Wall positions

• Openings

• Staircase & lift location

Structural drawings follow architectural intent.

One-Line Interview Answer (Perfect)

To read structural drawings, I start with the title block and grid layout, then study column, beam, and slab details with sections, notes, and BBS, and finally correlate them with architectural drawings for site execution.

Common Interview Follow-Up Questions

Q: What do you do if drawing and site condition don’t match?
A: Stop work and clarify with senior/consultant.

Q: Why are sections important?
A: They explain reinforcement anchorage and junction details.