This study investigates the feasibility of blending tire-derived waste with soil for use in integral-bridge abutment backfills. Reduced-scale physical models were constructed using an instrumented rigid box with a movable wall that reproduces the cyclic movements of an integral abutment subjected to thermal oscillations. The testing sequence included a series with eight tests with mixtures of tire buffings and sand as backfill material. Tire buffing contents from 0 % to 40 % by weight were examined under lateral displacement amplitudes of the wall equal to 0.4 % and 1 % of the backfill height. Results indicate that tire buffing-soil blends may be a technically viable option for integral bridge approach backfills because they can lower the lateral load acting on the abutment. Yet, the tire buffing content must be carefully selected to prevent excessive deformations that could impair structural performance.
The necessity for sustainable construction often leads to lightweight, large-span timber structures, which however exhibit a higher susceptibility to vibration. Within the presented ongoing research project, the focus is set on the vibration behaviour of existing timber pedestrian bridges aiming at determining, understanding and ultimately influencing the damping properties. This paper includes: (i) a brief state of the art literature review; (ii) a description of the project research framework; (iii) the experimental configuration, instrumentation and loading protocols; (iv) the system identification; (v) main conclusions and future research activities.
Due to serious damage to one of the piers of the concrete bridge, part of the road junction between Sofia Ring Road and one of the biggest boulevards in the city, there was a need for inspection, condition assessment and suggestions for refurbishment of the structure. The paper describes the activities related with the processes where except traditional engineering approaches – FEM analysis and details for strengthening, are involved new technologies for digital inspection – LiDAR scanning, Photogrammetry, Digital twin, BIM. Different solutions are proposed to the Owner of the bridge where the Key performance indicators (KPIs) from COST Action 1406 are considered.
Prestressed concrete is among the most used types of structural materials. Bridges with longer spans can be easily designed from individual segments which are subsequently connected by post-tensioning. In recent years, we have witnessed several failures of early post-tensioned bridges consisting of several segments (usually three or five). The significant decrease in prestressing resulted in the joints opening between the segments. As a result, our research focuses on an alert system based on up-to-date FBG sensors which monitor the joints in real-time. In the experiment, two types of sensors for joint monitoring were used. First, binary (tear) sensors that monitor the joint activity and second, sensors for continuous monitoring of joint opening. Moreover, the FBG strain gauge was used in the experimental campaign too. Before applying such a system, laboratory measurements were performed on post-tensioned segmental beams. The specimens were subjected to four-point bending loading scheme to verify the efficiency and accuracy of the newly designed sensors. Finally, the experimental program supported by the nonlinear numerical analysis confirmed that such sensors can be used on existing bridges. The coincidence of the results from the experiment and numerical modelling was good. Thus, such real-time monitoring will help the administrators of bridges manage them and react immediately after reaching the alert system's thresholds.
Scour is a primary cause of bridge failure during floods, yet its prediction is complicated by hydrological uncertainty and layered soil erosion. This study develops a life-cycle fragility assessment framework for bridge pile foundations subjected to flood-induced scour. A Seasonal Autoregressive Integrated Moving Average (SARIMA) model is used to estimate long-term scour depth from incomplete hydrological records. A three-dimensional finite element model (FEM) of the pile–soil system is then established to simulate structural behaviour. By integrating probabilistic scour evolution, time-dependent fragility curves are derived to quantify structural degradation over time. Results reveal that scour develops rapidly in the first 60 years and later stabilizes. The proposed framework provides a robust basis for risk-informed design and long-term resilience of bridge foundations exposed to flood hazards.
