The importance of the four-eye principle and site supervision

The issue of site monitoring of infrastructures come forward on the agenda of owners, planning engineers and users as a result of several unfortunate events - also in Germany.

Case studies are presented related to the hurricanes Lothar and Wiebke, damage events from the harsh winter of 2001/2002 with lots of snow, and caused by the buildup of ice and the formation of water pockets. The examples of rising structures show, why the causes of damage were the combination of a partially inexistent "Four-Eye Principle“, lacking site supervision, and poor execution of the works. The examples also illustrate that not only steel and timber roof structures, but reinforced-concrete and prestressed concrete structures, too, are not preserved from damage.

Finally, the potential danger existing in our buildings and the need for building checks throughout the entire life time of a building will be treated.