Conception de piles de pont préfabriquées répondant aux exigences de performances parasismiques

In the current context where many bridges in Quebec are reaching the end of their design life, it is necessary to build new sustainable infrastructure that meets current and future needs. With a growth in population and an increase in vehicles on our roads, new construction techniques must be developed to minimize the impact of construction activities. The Accelerated Bridge Construction (ABC) aims to use precast elements and minimize the installation of reinforcements on site. Although this technique has been used for several decades for large structures, this construction method has gained significant popularity since the early 2000s. For regions, such as Quebec, where seismic design imposes requirements to ensure high ductility for bridge piers, the use of precast elements for foundation elements such as piers is a major challenge. Indeed, structures built using this technique have connection joints that are often the weak points. Therefore, it is essential to design earthquake-resistant field joints while maintaining the integrity of the structure. The advent of new innovative materials, such as high-performance fibre-reinforced concrete (UHPC), characterised by exceptional mechanical properties in traction and compression, has made it possible to successfully rehabilitate bridge piers with many deficiencies regarding seismic design rules and to provide them with ductile behaviour. For existing bridges, the concrete cover around reinforcements at the base of the piers is removed and substituted by UHPFRC. This technique makes it possible to connect the overlapping bars in UHPFRC and eliminates splitting failure of the overlapped bars. The success achieved in reinforcing existing deficient bridge piers has therefore been adapted to new structures. A research program conducted at Polytechnique Montreal aims to develop fully precast piers and abutments designed to offer seismic resistance that meets current performance requirements. In these application UHPFRC are used in the connection between the precast elements to ensure continuity when subjected to the most demanding conditions for seismic design.