# Three Finite Element Models of the openLAB Research Bridge

## Abstract

From May 5 to May 7, 2025, extensive experiments were conducted on the openLAB research bridge. The test program was structured as follows:

* Day 1 (2025-05-05): Static and dynamic measurements in the reference state
* Day 2 (2025-05-06): Loading of the bridge using hydraulic jacks up to the ultimate limit state
* Day 3 (2025-05-07): Localized damage to the prestressing tendons (cutting wires at multiple locations)

This dataset includes three finite element (FE) models of the openLAB research bridge which were used to simulate the load tests conducted on Day 2. The load was applied locally to the prestressed element (PE) 2.1 (span 2, PE axis 1) using two hydraulic jacks, incrementally increasing the load up to a total of 400 kN.
The three FE models were independently developed using different FE software solutions and feature different element types:

* FE model 1: ATENA, volume element model
* FE model 2: DIANA FEA, volume element model
* FE model 3: SOFiSTiK, combined beam-shell element model

The dataset includes all necessary input files to recreate the FE models in their respective software environments and reproduce the simulation results of the load tests.


Related resources:
* Digital documents of the openLAB and BIM models: [Digitale Unterlagen der openLAB Versuchsbrücke (Stand 2025-11-29)](https://doi.org/10.25532/OPARA-1010)
* Experimental regime and environmental data: [Experimental procedure for the tests on the openLAB from 2025-05-05 to 2025-05-07](https://doi.org/10.25532/OPARA-1012)
* Load and deflection: [Monitoring Data of the openLAB Research Bridge – Load Test on PE 2.1](https://doi.org/10.25532/OPARA-852)
* Distributed strain measurements: [Distributed fiber optic sensor data of the openLAB loading tests from 2025-05-05 to 2025-05-07](https://doi.org/10.25532/OPARA-1011)
* Crack pictures and surface crack widths: [Photographic documentation of crack development on the openLAB during the loading test on 2025-05-06](https://doi.org/10.25532/OPARA-898)

## Repository Structure

**Note:** In all cases, a valid license is required to use the FE models and run the FE simulations.

### 📁 01_ATENA

The directory `01_ATENA` contains the GiD project (`./786.gid`) with the associated input files required to build and run the ATENA FE model.

#### Input file overview:
* `*.geo`: Geometry information
* `*.msh`: Mesh information
* `*.mat`: Material information
* `*.cnd`, `*.lin`, `*.prb`, `*.rdr`, `*.tree`, `*.uni`, `*.vv`: GiD internal project files
* `*.bat`: Optional solver launcher scripts

To open the FE model, use the Software GiD and select the project file (`./786.gid`). The geometry, mesh, material, boundary condition and monitor points will load automatically. The ATENA model parameters can be viewed in 786.inp or through GiD’s ATENA interface.  To reproduce the nonlinear analysis, an ATENA solver is required.
The subdirectory `./786.gid/ATENA_calculations/` contains simulation data of the last load step. Note that full ATENA simulation step files are not included due to size constraints.
Additionally, the file `./786.gid/ATENA_calculations/monitors.csv` contains displacement data of selected monitor points of all load steps (e.g., for load application point x = 24.3 m).
The FE model was created with **GiD version 16.0.8** and calculated with **ATENA version 6.0.0.24064**.

### 📁 02_DIANA-FEA

The directory `02_DIANA-FEA` contains `*.txt` files to create the openLAB research bridge using the FE software DIANA FEA.

#### File overview:
* File 01: General settings of DIANA FEA.
* Files 02–04: Geometric model (derived from the as-built documentation and assembly drawings)
* File 05: Material definitions for concrete, prestressing steel, and reinforcement.
* File 06: Geometric properties of the reinforcement (bar diameters).
* Files 07-08: Support conditions of the foundations as well as the connections of the bearings on axis 30 and the railway sleepers to the superstructure
* File 09: Applied loads
* File 10: Assignment of material and geometric properties to objects
* File 11: Meshing procedure
* File 12: Analysis settings for nonlinear FE analysis  

The terminology follows the commands of DIANA FEA, although some designations (e.g., for concrete types or reinforcement elements) are derived from German language. 
The FE model was created with **DIANA FEA version 10.10**.


### 📁 03_SOFiSTiK

The `open_LAB.dat` file in the directory `03_SOFiSTiK` contains the input data for the SOFiSTiK FE model. The file is written in the **CADINP-command language** and is designed to be executed using the SOFiSTiK Text Editor (_TEDDY_).
The file is written in German CADINP syntax. English comments have been added for accessibility. These comments explain the purpose of each section, command, and parameter.
To build the FE model and start the simulation of the load test open the file in a compatible _TEDDY_ version and execute all modules. Ensure that all modules are activated beforehand.
After running the script, a `*.cdb` database is created for post-processing.
The `*.dat` file was created in **SOFiSTiK version 2024-4**.


## Availability, Copyright and Funding

This dataset is available as open data.

**Authors:** Eisermann, Cedric and Sprenger, Bjarne and Lila, Kleo and Schnellenbach-Held, Martina and Marx, Steffen
**DOI:** https://doi.org/10.25532/OPARA-1030
**Licence:** http://creativecommons.org/licenses/by-sa/4.0/

This research was funded by:
- Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) as part of the priority program 2388 “Hundred plus – Extending the Lifetime of Complex Engineering Structures through Intelligent Digitalization” (central project: 501804558, subprojects: 501496870 and 501808860)
- Federal Ministry of Transport, Germany, as part of the research project ANYTWIN ("Development and standardization of methods for measurement-based structural safety assessment of highway bridges and integration into digital twins"; funding reference: 01F2248B)
