Below we describe the functional use cases for the technologies known commonly as construction verification in plain English to help you understand it's practical benefits.
While some of these checks have always taken place on projects, traditional methods focus on specifics and cover only a small percentage of project work. Software supported verification unlocks new methods and applies these to whole projects but is reliant on both a 3D digital model and a way to position data collected on site to it with a known accuracy.
The spectrum of use cases is likely to grow, but at this point in time these three approaches for construction verification are currently achievable with existing processes and technology with appropriate planning and resources.
Progress monitoring
This process uses photography or laser scan data to track the progress of site work against a digital model.
It has a lower requirement of accuracy because it is primarily about establishing the presence of objects. This approach does require frequent collection of data to ensure a meaningful record.
Using this approach could allow a site to track the progress of planned work against real activity on site and anticipate emerging programme or logistical problems that otherwise remain unnoticed until they cause delays or disputes.
Accuracy of as-built conditions
Comparing laser scan data with models at or near the end of a project can serve to assist in the production of more accurate as-built information. This process can involve a series of scans throughout a site as a project reaches completion to capture what has been built and to make a comparison. The site may need to be scanned and re-scanned as works are concealed, for example when a suspended ceiling goes up.
Accuracy in as-built models should be defined by the reason for the as-built information. This could be to help an operative find and maintain a system concealed above a ceiling which arguably could meaning opening the correct ceiling tiles. Or to allow a client to know that the designed lettable area has been achieved in the completed project, in which case the expectations could be dependant on the square footage value.
Using this approach can support contractors or subcontractors when they are documenting the changes that have occurred during an installation to ensure the as-built record reflects what has been built.
Accuracy during construction
Like accuracy of as-built conditions, this process involves comparing models with laser scan data. However, to verify during construction many more increments of data collection are required throughout the project because this follows the construction as it occurs.
To be meaningful, data collected for this approach requires a high level of positional accuracy.
Using this approach can check the position of installations during construction and identify differences from the design. Establishing the impact of these differences can reveal future clashes with following work much earlier and prevent delay from re-work that would be required without this insight. This process also provides the information required for progress monitoring.