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Abstract
The first part of this article presents the feasibility study of a new structure for a 10-m-span bridge deck, taking into account the possibilities offered by new and high-strength materials and the advantages of a traditional environmental-friendly material. This 10-m-span element is formed by wooden beams braced at the ends, on supports atop a thin slab (7 cm thick) made of pre-cast ultra-high performance fiber-reinforced concrete, and fiber-reinforced polymer at the bottom of the wooden beams. The issue of connecting the ultra-high performance fiber-reinforced concrete to the wooden beams of high but possibly mismatching performance is addressed. An adhesive connection has been considered, following an increasing trend for composite structures where materials savings and optimal performance are searched in every component. The second part of this article presents the vibration-based damage monitoring. Small localized damages are hardly detected by global monitoring methods. The effectiveness of vibration-based detection depends on the accuracy of the modal parameter estimates and is limited by the low sensitivity of the modal parameters to a local stiffness reduction. A local reduction of stiffness related to frequency changes less than 1% was successfully detected on the bridge mockup after loading up to the serviceability limit state (SLS). Such a small decrease in the stiffness was not detected by the monitoring of the static load-deflection measurements but was confirmed by nonlinear local strain measurements. Statistical subspace-based damage detection successfully detected the change of the modal parameters of the investigated structure. Further analysis with a finite element model was conducted for assessing the consistency of the expected location and extent of the damaged elements.