Retrofit strategies for mitigating progressive collapse of hybrid and traditional cable domes: Fid-Bau Portal

Retrofit strategies for mitigating progressive collapse of hybrid and traditional cable domes

Asghari, R. / Abedi, K. / Chenaghlou, M.R. / Shekastehband, B.

Abstract This paper is concerned with the retrofitting of hybrid cable domes against progressive collapse using viable proposed strategies. Hybrid cable domes as the composite forms of tensegrity rings and cable domes with appropriate structural efficiency offer promising alternatives for traditional cable domes with rigid compression rings. A hybrid configuration, namely, a hybrid cable dome with a tensegrity ring and a traditional Levy cable dome with a rigid ring, is assessed against progressive collapse using the Alternate Path (AP) method. The studies were carried out in two phases. In the first phase, using static and dynamic alternate path analyses, the progressive collapse of the structures due to loss of critical members was assessed. In detecting critical members, two criteria were employed based on the members' demand and frequency of damaged structure. According to the obtained results, lower hoop cables were identified as critical members whose sudden loss resulted in progressive collapse. In the second phase, the effectiveness of four proposed retrofit strategies, entitled employing force limiting devices (FLDs), strengthening critical struts, adding an inclined bracing cable net in hoops, and using a network of bottom cables, were evaluated aimed to improve progressive collapse resistance. Based on the results, the proposed network of bottom cables was determined as the best retrofit method for mitigating the progressive collapse of hybrid and traditional cable domes.

Highlights • In this paper, a new hybrid cable dome together with a traditional cable dome was considered for the progressive collapse resistant design of them. • In first phase of paper, using static and dynamic alternate path analyses and also frequency analyses, the definite critical members are detected. • In the second phase, four different retrofitting methods are evaluated to resist the progressive collapse and provide safe alternate load paths. • Using of FLDs or strengthening of critical struts, do not provide a safe alternate path. • Adding cross bracing cables between the struts of any hoops or adding a bottom cables net provided a safe and reliable alternate load path.