Roof Structure of the Bell Tower of St. Michael’s Church in Vienna - Experiences with Obvious Need for Reinforcements

Abstract

In 2022, the rectory of the parish of St. Michael’s Church in Vienna was faced with a report on the overall health, as well as plan documents containing reinforcements of the historic timber structures as part of the bell tower. The report, signed by an engineering office following an on-site inspection by a carpenter, included a proposal for reinforcements. This measure is expected to prevent structural failure due to wind actions, such as rocking. Notably, the historic structure, built in 1596, has remained intact and without significant issues until the present day. Against the background of missing sound facts for decision-making, an agreement with all stakeholders on a more professional procedure for fact-finding was reached. A more comprehensive inspection on site and subsequent structural assessment revealed, that the timber structure was rather prone to slide than to rock and structural integrity could be proved by more accurate structural modelling and realistic loading scenarios according to the provisions of EN 1990 [2] and EN 1991-1-4 [3] Therefore, the characteristic of this monument could be preserved without further changes respective amendments.