Transforming the Static System of Prestressed Concrete Bridges Using UHPFRC

The rehabilitation of existing bridges should always be the first investigated solution because it usually reduces construction costs, environmental impacts, and traffic disruption. Nonetheless, bridges are too often replaced due to the lack of effective structural strengthening schemes. The latter reason is particularly true for short-span, simply supported structures that cannot plastically redistribute additional loads. Ultrahigh-performance fiber-reinforced cementitious composites (UHPFRCs) and their technology offer new solutions for enhancing the performance of existing reinforced concrete bridges. The UHPFRC technology allows for the rehabilitation and strengthening of the deck and girder of bridges due to its high mechanical properties and high durability. Conventional UHPFRC interventions are realized by casting an additional layer on the deck, but this solution enables only limited improvement in the case of simply supported structures. This manuscript presents the innovative strengthening concept for short-span concrete bridges with UHPFRCs, consisting of clamping supports to modify the boundary conditions and, thus, the static system. This intervention was recently realized on a prestressed concrete bridge with a single span of 35 m built in 1958 in Switzerland. The bending structural capacity increased by 47%, allowing for the widening of the deck from 5.3 to 7.9 m. Load tests were performed before and after the intervention, and data collected validated the strengthening scheme. Life-cycle cost and environmental analysis showed significant savings (42% and 55%, respectively) compared to the previously proposed deconstruction-reconstruction solution. This case study demonstrates the potential of this strengthening strategy for managing short-to medium-span bridges, respecting sustainable and cost-effective infrastructure management.