As-Built Drawing
Definition
A drawing that records what was actually constructed, as opposed to the approved design drawing. Discrepancies between the two are a common source of reduced structural capacity.
- Contrasts with
- Approved design drawing
- Records
- What was actually constructed
- Common issue
- Discrepancy with design reduces structural capacity
Common questions
Why do investigators compare as-built drawings against the design set at all?+
Field substitutions, undocumented changes, or contractor shortcuts often go unrecorded in the design drawings, so comparing the two can reveal whether a structural failure traces to a deviation introduced during construction rather than a design flaw.
What happens when no as-built drawing exists for a failed structure?+
Investigators then have to reconstruct as-built conditions through physical measurement, material testing, and sometimes demolition survey, which is slower and less certain than working from documented as-built records.
Related terms
- Alternate Load Path
- A route by which loads can be redistributed around a failed element without causing progressive collapse. Its presence or absence is central...
- Collapse Mechanism
- The kinematic sequence of element failures that produced the observed final geometry of the collapse, reconstructed by investigators from wreckage patterns and...
- Load Path
- The route forces travel through a structure from their point of application to the ground. When one element fails, loads redistribute onto...
- Progressive Collapse
- A failure mode in which local structural failure triggers a sequence of failures in adjacent members, resulting in collapse disproportionate to the...
- Tie-Force Method
- A prescriptive design approach requiring minimum tensile continuity across connections so that elements can hang or span around a failed support rather...