# Integration of BIM Tools for the Facility Management of Railway Bridges
## 4 Development Method  
Figure 2 shows a proposed methodology for creating a BIM tool that generates automation between the parametric BIM model and a standardized database for the monitoring of railway bridges. The methodology consists of four stages: (1) Collection of the BIM model and creation of the automated spreadsheet in MS Excel(r); (2) Creation of algorithms for the export and import of information using Dynamo; (3) Development of a workflow for the BIM/data automation tool; and (4) Confirmation of the BIM/data automation as an initial step towards digital twins for the facility management of railway bridges.  
In the first stage, the damages to be inspected are defined along with their respective intensities and categories, parameters that are provided by the inspection standard. Thanks to the study of this monitoring regulation, it is possible to create an automated spreadsheet that will serve as a database, as it includes the intensities, categories, and parameters to inspect the bridge. This automated spreadsheet consists of dropdown lists for the intensities whose values vary depending on the damage situation of the elements. When an intensity is selected, the cell will obtain a color along with its respective intensity detail for each bridge element, ultimately providing the damage severity level, which is derived from a formula proposed for this research that weights all damage intensities of the element to give this value. This value determines the color that the element will have in the BIM model. Almost simultaneously, the BIM model of the infrastructure is parameterized in the BIM software for each bridge element with the damage intensity details, creating dropdown lists similarly to the spreadsheet. This ensures that when programming the automation between the automated spreadsheet and the BIM model, it is more accurate, avoiding errors, and ensuring that the information of the elements is consistent in both content and visualization during operation. In addition to parameterizing the model by adding the damage intensities, each element is assigned a variable named \"damage severity level\", where the value calculated by the proposed formula will be stored. Finally, to ensure that the elements obtain a color according to their damage severity level, filters are created in the BIM software so that based on these values, the element takes on its respective color, allowing the visualization of the damage level of each element and, consequently, the overall state of the railway bridge.  
The second stage focuses on creating algorithms to extract and import information between the parameterized model and the automated spreadsheet, using a BIM software extension that enables visual programming for this information exchange and flow, producing a bidirectional flow between both parts. Two separate programming files are created, one for extraction and one for import, but they are used together to generate the bidirectional flow.  
The third stage involves creating a workflow for the BIM tool, which consists of implementing the programmed algorithms in a specific order for data transfer, starting with data export from the model to the spreadsheet and then importing information back to the model from the spreadsheet. This workflow order is explained because the automated spreadsheet serves as the data collection point, where the damage severity level value is obtained and imported into the model, generating the color change of the elements depending on their structural condition. Additionally, this order is followed because it is easier to conduct field inspections with the parameterized BIM model in a viewer that allows selecting bridge elements and recording the damage intensity and/or comments, rather than carrying out the inspection with the spreadsheet.  
Finally, in the fourth stage, the BIM tool, consisting of BIM/data automation, is verified to ensure it functions without visualization, information, and/or programming errors, making it ready for use.  
Figure 2: Flowchart of the developed methodology.