A New Post-Installed Reinforcement System to Extend Lifetime of Existing Bridges and Tunnels as Contribution to Sustainability

Most of the infrastructure constructions in the industrialized countries were erected between 1960 and 1990 and are therefore now between 30 and 60 years old. In the course of recalculations of bridges, deficits in load-bearing capacity frequently arise due to aging of the structures, the increasing loads on these structures on the one hand and the changes in the design codes on the other hand. Studies showed deficits in the load-bearing capacity of existing structures especially regarding the shear load capacity. Often, a complete replacement of these structures is planned, which leads to high investment costs but also to massive traffic disruptions due to the complete or partial closure of the structure. Studies carried out showed the environmental impact of closing a bridge for one day and for one and a half years compared to the impact of demolition and rebuilding and the impact of strengthening of the existing structure. The comparison shows clearly that strengthening of existing structures is far more sustainable than building a new bridge. It can also be seen that the impact of pure demolition and replacement construction on the global warming potential is negligible compared to the impact of affected traffic. Therefore, in the last decade, research has been conducted at the University of Innsbruck, Austria, on new, efficient post-installed reinforcement systems with the help of which the lifetime of existing infrastructure buildings can be significantly extended. These new systems have to be installed in the existing structure as quickly as possible and without disturbing the traffic. This is the only way to keep traffic disruption and environmental impact to a minimum. In particular, the focus was on shear reinforcement with post-installed concrete screw anchors as shear reinforcement. The paper thus aims to show the positive effects of strengthening measures compared to rebuilding on global warming and minimizing the use of natural resources.