Delayed catastrophe of a steel roofing structure of a shopping facility

Abstract

Abstract The work describes the actions taken as a result of an unforeseen disaster of a shopping facility that had been in operation for several decades. A considerable part of the facility's roof structure unexpectedly collapsed under the impact of a snow layer, whose thickness did not exceed the limit value specified in the current regulations. The roofing was made of steel segmental truss girders (4 × 6 m) with a span of 24 m, joined together by bolts and welds. After securing the facility against a possibility of further collapse, the extent of the damage was investigated. An attempt was made to identify faults in the structural elements and in the connections made several years earlier, as well as possible mistakes made during the modernization works several months before the disaster. The actual strength parameters of the steel structural elements and joints were determined. The effort of basic structural elements was analyzed, with particular emphasis on the state of connections of successive segments of the damaged girders. The causes of the disaster were determined. The work is concluded by presenting a concept and conditions for lifting and reconstructing the damaged roof. It is worth highlighting that the roof was lifted as a whole, without the need to disassemble purlins, steel sheets and insulation. The advantages and disadvantages of different types of butt joints used in the construction were evaluated. Making use of the results of the investigation, the recommendations concerning the design, construction and operation of public facilities were formulated and relayed to participants of the investment process.