Structural and Technological Aspects of the Historical Floors Replacement

Abstract

The article presents structural and technological problems resulting from the use of historical floors in the process of planned renovation and modernization. In the three-story building, built at the end of the nineteenth century, there was significant damage caused by warfare. At the stage of post-war reconstruction, some structural elements were adapted to new functions. Structural walls, made of ceramic bricks, were suitable for further use, without the necessity of additional reinforcement. Damaged fragments of the floors were reconstructed. Due to the elevation of the street level, the rebuilt ceiling above the ground floor was weighted with a 600 mm layer of brick debris or crushed brick. In an additional layer, water-supply systems were located. In the following years, the building was superstructured by one storey. Structural walls made of ceramic bricks were covered with channel plates. After several decades of usage, the user decided to change the function of the rooms, which involved transferring additional loads to existing structural elements, i.e., floors, walls and masonry spot footing. As a result of the research, calculations and consultations with the conservator, it was recommended to strengthen the existing channel floor. After additional tests involving the trial loading of floors, they were qualified for modernization without the necessity of additional reinforcements. During demolition works aimed at replacing the elements of sanitary installations, significant damage to steel beams, which were the supporting structure of floors above the ground floor, was identified. As a result, all works were stopped and the concept of using existing floors was abandoned. On the debris layer, used as a formwork, a newly designed beam-and-slab floor was made, and then the stone vaults and the debris-ceramsite filling were demolished and utilized. At the request of the conservator, fragments of destroyed steel beams were left as a so-called “witness” of the history of the building. The authors of the abstract draw attention to the significant problem associated with the use of several hundred-year-old structural elements in the processes of modernization of objects. In the analysed case, conducting meticulous calculations and tests consisting of a trial loading of a degraded structure did not result in obtaining the results qualifying the structure for replacement. At the stage of construction works, the potential danger was identified. This leads to the conclusion that the process of modernization of historical buildings must be carried out under the constant supervision of construction designers and architects.