26 February 2026
New methods for estimating the remaining service life of concrete bridges
Many concrete bridges in Sweden are approaching or have already exceeded their original design service life. In her doctoral thesis at Luleå University of Technology, Silvia Sarmiento shows how combining full-scale experiments, probabilistic analysis and numerical modelling can provide more reliable assessments of the remaining service life of existing bridges.
“To determine how long a bridge can continue to be used safely, we need to address uncertainties in materials, loads and degradation processes,” says Silvia Sarmiento, PhD candidate in Structural Engineering at Luleå University of Technology.
Integrating experiments and modelling
In the thesis Remaining service life estimation of existing concrete bridges through probabilistic and reliability analyses, she studies two representative bridge types: a prestressed concrete bridge that has already been demolished and a reinforced concrete railway bridge constructed as a test object. Sensor measurements and load tests are used to calibrate finite element models, which are then linked to reliability-based analyses.
“By combining experimental data with probabilistic methods, we obtain a more realistic understanding of how structures age and how reliability levels decay over time,” she says.
The work also includes the development of efficient computational approaches that reduce the need for extensive simulations, making the methods more practical for real-world applications.
Silvia Sarmiento has defended her dissertation in Structural Engineering.
Societal value for infrastructure management
The research provides clear societal benefits for the management of road and railway infrastructure. Improved estimates of remaining service life enable more targeted maintenance planning, reducing the risk of unexpected failures as well as premature replacement of structures that still have capacity.
The methods offer decision-makers stronger support when prioritising maintenance actions, which is increasingly important as large parts of the infrastructure network age simultaneously and available resources are limited. In the long term, this can contribute to improved traffic safety and more sustainable use of public infrastructure investments.
“With better decision support, resources can be used where they have the greatest impact while maintaining a high level of safety,” says Silvia Sarmiento.
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