The Merksem Viaduct on the R1 around Antwerp, constructed between 1965 and 1969, is undergoing changes as part of the Oosterweel project. To make room for a new tunnel, the existing southwestern viaduct will be demolished, leading to displacement and additional lateral forces and bending moments in the pile foundation. Due to uncertainties about the pile foundation, the structural safety was questioned. The solution involved applying a ring of jet grout columns around the existing foundation. This paper details the geotechnical and structural design approach for the jet grout ring, emphasizing the multidisciplinary process and the effective design method provided. The design ensures the stability of the viaduct during the construction of the new tunnel. It also addresses the challenges of force transfer between the existing structure and the new jet grout ring. The approach aims to maintain the integrity and safety of the viaduct throughout the project.
Dam et al. (Wed,) studied this question.