Advanced Simulation
Across Europe - Germany included - bridges are aging. Many were built in the post-war economic boom and now carry traffic loads they were never designed for. Official sources describe an unfavourable age structure in the federal network, with many bridges now over 50 years old (see BMDV 2022 and BASt Brückenstatistik 2025). [1] [2]
According to the Deutsche Bahn (DB), as of 2023, there are approximately 25,216 railway bridges across the German rail network. Notably, over 11,000 of these bridges are more than 100 years old, highlighting the aging nature of the infrastructure. [3]
These structures, once marvels of engineering, are now reaching or have perhaps exceeded their intended service life. The consequences are real: restricted traffic, rising maintenance costs, and even closures.
In April 2024, the collapse of a section of Dresden’s Carola Bridge [4] was a wake-up call to the public and policymakers alike. It wasn’t just about one bridge. For many, this was a signal that decades of underinvestment, deferred maintenance, and heavier-than-anticipated traffic have pushed many parts of Germany’s infrastructure to the edge.
The good news? Not every aging bridge needs to be torn down.
Bridges of Hamburg
Preserving infrastructure is the smarter, greener choice
Both the financial and the environmental cost of demolishing and rebuilding a bridge is enormous. Replacing a mid-sized or large urban bridge in Germany typically takes 2–5 years and costs anything between €50 to €500 million (depending on size), not to mention the societal impact of traffic congestion, supply chain delays, and increased CO₂ emissions from detours and construction activity.
Instead, structural engineers are increasingly turning to detailed assessment and reclassification of existing structures. The goal: determine how much residual capacity remains, where reinforcement might be needed, and how to extend a bridge’s life safely and economically.
This shift in mindset - from “demolish and replace” to “evaluate and optimize” - requires modern tools. Specifically, it requires simulation software capable of advanced analysis scenarios that reflect the real-world complexity of aging infrastructure.
One such tool, that is at the forefront of this field is BRIGADE/Plus.
The complexity of modern bridge rehabilitation
Assessing an existing bridge structure is in many ways different from designing a new one. In new design, assumptions about material properties, loading, and construction sequence are well controlled. In the evaluation of existing bridges, engineers might have to account for a number of uncertainties and degradation effects, such as:
- Material deterioration, including cracks, corrosion of reinforcement, or creep deformation
- As-built deviations, such as misaligned supports or undocumented modifications
- Accidental loads or damage from collisions, fire, or settlement
- Time-dependent behaviour, including prestress losses and shrinkage
In this context, linear static analysis often fall short. Instead, engineers require a flexible toolkit to simulate or analyse:
- Nonlinear behaviour of both materials and geometry
- Post-buckling stability of slender elements
- Contact and separation in degraded joints or bearings
- Dynamic response under moving loads, including resonance checks
- Staged construction or repair sequences for reinforcement strategies
BRIGADE/Plus provides exactly that: a full-spectrum simulation environment, tailor-made for bridge engineers.
A bridge engineer’s toolkit – inside BRIGADE/Plus
BRIGADE/Plus is built on top of the trusted Abaqus FEA platform but customized specifically for bridge analysis. Here are some of the features that make it ideal for the assessment, rehabilitation, and upgrade of existing infrastructure.
1. Nonlinear material behaviour
With aging concrete structures, cracking, crushing, and stiffness degradation must be considered. BRIGADE/Plus includes the Concrete Damage Plasticity (CDP) model, which allows engineers to simulate:
- Loss of capacity due to cracking
- Load redistribution under non-linear conditions
- Performance under accidental or ultimate limit states
This model is particularly relevant for evaluating residual load-bearing capacity.
Analysis of the residual load-bearing capacity of the foundations at the Årsta Bridge (Stockholm Sweden) before reinforcement work was carried out.
2. Post-buckling and collapse analysis
When evaluating slender structural components (e.g., girders, deck slabs), buckling risk must be carefully assessed. BRIGADE/Plus supports both:
- Eigenvalue buckling to identify critical load factors
- Nonlinear RIKS analysis to simulate collapse behaviour beyond peak load
This enables engineers to test worst-case scenarios, including local failure in damaged structures and stability under asymmetric or staged loading.
Example of buckling analysis of existing steel bridge
3. Staged construction & repair sequences
When reinforcing an existing bridge, it’s crucial to simulate how the structure behaves before, during, and after each intervention step. BRIGADE/Plus allows users to:
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Activate/deactivate elements and supports in a step-by-step timeline
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Simulate segmental repair or cantilever strengthening
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Assess redistributed internal forces over time
This supports better planning, fewer surprises during fieldwork, and better alignment with as-built rehabilitation sequences.
4. Extended free body cut (FBC)
In real-world bridges, engineers often need to evaluate internal forces not just in global models, but in localized sections affected by damage or repairs.
BRIGADE/Plus offers a unique Extended Free Body Cut tool that extracts equilibrium-consistent internal forces (N, V, M, T) from any cross-section, regardless of mesh or element type. This is invaluable for:
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Creating section-specific load combinations
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Comparing simulation results to manual checks
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Analysing partial sections
You can read more about the Extended FBC functionality here: Extended Free Body Cut
An example of where the Extended FBC feature gives the bridge engineer a good understanding and overview of the structural behaviour.
5. Contact modelling for realistic load transfer
Bridge bearings, joints, and interfaces are critical and often degraded in aging bridges. With BRIGADE/Plus, engineers can model:
- Sliding or frictional contacts (e.g., bearings with wear)
- Contact damping in dynamic scenarios
- Rigid-to-flexible or flexible-to-flexible interactions
These features improve realism in models, especially for local analyses around damage zones.
6. Dynamic response of moving loads
Many German railway bridges must be evaluated for vibration and comfort criteria under high-speed trains. BRIGADE/Plus includes:
- Built-in HSLM-A vehicles for Eurocode-compliant railway analysis
- Simulation over a range of speeds to detect resonant peaks
- Automatic result envelopes for displacements, accelerations, and forces
- Efficient task handling via the BRIGADE Job Processor, which distributes load cases intelligently and supports parallel computation.
You can read more about the Best Practices for Dynamic Analysis of Bridges here: Best Practices for Dynamic Analysis of Bridges
Animation of the bridge’s dynamic response and the moving train load represented as concentrated loads.
Engineering smarter, not just harder
What Germany faces is not just a technical challenge, but a societal and environmental one. Every bridge that can be safely preserved through simulation, assessment, and reinforcement represents:
- Millions saved in construction costs
- Years saved in permitting and traffic disruption
- Thousands of tons of CO₂ not emitted
- A win for the public, for planners, and for the planet
But making that possible requires giving engineers the tools they need to confidently say what can stay, what must go, and what can be upgraded.
BRIGADE/Plus provides that confidence.
What Comes Next?
As Germany launches large-scale infrastructure programs through 2035, engineers and consultants will need to handle thousands of projects under tight deadlines. That means:
- Assessing hundreds of existing structures in parallel
- Running dozens of alternative analysis scenarios per structure
- Automating design checks and reporting
- Scaling across teams and regions
With its robust solver, bridge-focused user experience, and automation-ready architecture, BRIGADE/Plus is already in use by firms across Europe who specialize in bridge rehabilitation and safety assessment.
Conclusion
In a world where infrastructure is aging faster than we can replace it, we can no longer afford to treat every old bridge as a problem to demolish. We need to treat them as engineering challenges to solve. And that means having the right tools at hand.
BRIGADE/Plus is not jus an analysis tool. It is a decision-enabling platform that gives engineers a better understanding of the structure they are investigating.
If you're facing challenges with analysis of aging infrastructure, you are welcome to talk to us. We can supply the tools that let you find out what can be saved, reinforced, or optimized.
Here you can read how others have leveraged on BRIGADE/Plus (and BRIGADE/Standard) in their work with both new and existing bridge structures.
