WBS with example, levels and code

A Work Breakdown Structure (WBS) is a hierarchical, deliverable-oriented breakdown of the total project scope into smaller, manageable parts. Each level adds detail, and each item carries a code.

Four-level WBS of a rural road with a bridge project

Level 1  1.0 Rural road project
Level 2    1.1 Preliminary works
Level 3      1.1.1 Survey and design
Level 4        1.1.1.1 Topographic survey
Level 4        1.1.1.2 Geotechnical investigation
Level 3      1.1.2 Land and permits
Level 2    1.2 Road works
Level 3      1.2.1 Earthwork
Level 4        1.2.1.1 Clearing and grubbing
Level 4        1.2.1.2 Cutting and filling
Level 3      1.2.2 Pavement
Level 4        1.2.2.1 Sub-base and base
Level 4        1.2.2.2 Bituminous surfacing
Level 2    1.3 Bridge works
Level 3      1.3.1 Substructure
Level 4        1.3.1.1 Excavation and foundation
Level 4        1.3.1.2 Abutments and piers
Level 3      1.3.2 Superstructure
Level 4        1.3.2.1 Girders
Level 4        1.3.2.2 Deck slab
Level 2    1.4 Closure
Level 3      1.4.1 Testing and handover

Levels and coding

The code shows the parent of each item (1.2.1.1 belongs to 1.2.1, which belongs to 1.2). Cost, duration and the responsible person are attached at level 3 or 4.