Full scale laboratory test of trough bridges

Improving current loads standards and regulationswith a more realistic evaluation of the capacity of reinforced concrete trough bridges.

Goal

The scope of this project is to improve current loads standards and regulations by providing a more realistic evaluation of the capacity of reinforced concrete trough bridges. The methodology that will be used include testing of two real scale bridges in the lab, development and testing of scaled down bridges, finite element analysis and evaluation of structural reliability. The project will also deal with finding the actual distribution of the train loads in the bridge. The experimental campaign includes the following tests to evaluate the load at service and fatigue limit state.

Project status and results

In 2022, the casting of two real scale trough bridges finished, and activities related to procurement of equipment to carry out the testing in 2023 took place. Controlled laboratory experiments assess structural performance, focusing on the slab and beams' stiffness loss, cracking, and force redistribution are ongoing. The bridge has been subjected to dynamic tests up to 10 million cycles, replicating 50 years of service traffic. Fatigue verifications based on Eurocode EN1992-1-1 and fib Model Code 2020 have been performed alongside reliability analysis using the First-Order Reliability Method (FORM) to evaluate structural safety levels and derive partial safety factors. Results show evident fatigue damage in the slab's tensile zone, and stiffness degradation.