In the course of building maintenance, the recording of the actual condition as well as the documentation of the planned and executed work is of key importance. Building diagnosis data can be implemented in BIM in an interface-open way. This creates a kind of digital building book that bundles all relevant data in an IFC file and can represent it clearly. The data is secure, compact, and freely available to all parties involved.
With thorough planning, BIM models sometimes describe the target state extremely precisely. However, the actual state after construction has hardly ever found its way back to the corresponding model. Accordingly, the model is primarily suitable for planning a new building, but less so for planning any maintenance measures that may be necessary later. To change this and thus avoid the technical loss of value of the BIM model after the construction phase, the Institute for Building Materials Research (ibac) at RWTH Aachen University is researching measures for BIM-based building maintenance.
Ideally, building diagnosis provides information on the following component properties:
- concrete cover
- reinforcement layer
- carbonation depth
- chloride content
- corrosion probability
- crack pattern
- damaged areas
An appropriately enriched model offers significant possibilities for automating and supporting maintenance planning and execution, e.g., through user-friendly access to diagnostic data. For example, the corrosion probability can be stored and visualized in the BIM model as a result of a two-dimensional half-cell potential mapping.
In the example, the free BIM viewer BIMvision (Datacomp) was used. The objects can be colored according to their attribute value via the “Advanced Reports” plugin. Based on the condition recording, the components can now be efficiently assessed for their repair needs. Diagnostic results can be variably shown and hidden. Individual properties or their combinations can be viewed. Two-dimensional scans can be displayed in superimposed layers. In addition, Advanced Reports can be used to export the diagnostic data from the BIM model into tables.
In addition to the measured variables such as the carbonation depth, other (calculated) information can also be displayed, such as the 5% quantile of the concrete cover of the front reinforcement layer. The three-dimensional visualization enables immediate identification of damage cases and causes. If, for example, the concrete cover is very high on one side of the column and very low on the opposite side, then the reinforcement cage was probably not centrally placed during installation.
For further information, please refer to the open-access publications of the research (https://doi.org/10.3390/constrmater2040020, https://doi.org/10.3390/civileng4010012) or to Hendrik Morgenstern (morgenstern@ibac.rwth-aachen.de).