In the course of the condition investigations for the 2020 planning, structural engineers had determined that the tower was not stable. Overloaded pillars and arches in the basement and on the ground floor threatened to fail. The STSG had to react with an immediate closure and initiated emergency stabilisation to ensure stability and restore access to the books as quickly as possible. The focus was on three free-standing pillars and three wall pillars made of natural stone. They received steel chords that were additionally encased in concrete. This allows them to reliably transfer the enormous loads back to the foundations. In order to be able to completely enclose the wall pillars, the southern cellar wall had to be exposed from the outside.
The main causes of the damage are alterations made to the static structure as early as the 17th century, material fatigue in the historical supporting structures and the heavy loads caused by the rich library holdings. These problems must now be fundamentally repaired in the medium term, and the emergency stabilisation measures were only the first step in this process. Structural engineers, surveyors and wood protection experts are now examining the masonry and the wooden structures in detail in order to be able to plan the renovation that was planned from the beginning.
Meanwhile, the Gotha Research Library of the University of Erfurt is facing a major challenge. Now that the book collections are accessible again, their removal from storage must be planned - an important prerequisite for the renovation, but also for the examination of components that are currently out of place. With 300,000 volumes in the tower, of which 4,500 shelf metres must first be cleared out, this is not only a logistical task, but must also be done under static supervision. If the load is removed too quickly or unevenly, the building structure would relax uncontrollably and could suffer additional damage. Clearing is expected to begin in autumn 2021.
The renovation of the east tower is part of the ongoing 60-million-euro renovation of Friedenstein Palace and the ducal park, which is funded half by the federal government and half by the state. Despite the extensive construction work, significant parts of the castle are open to visitors.