Research On Seismic Fragility Of Single-layer Reticulated Domes Based On OpenSees

Seismic fragility analysis of single-layer reticulated domes can be used to predict the probabilities of different damage levels under different earthquake intensity levels. It is a fundamental and important element in seismic reliability analysis of single-layer reticulated domes and other types of earthquake damage prediction. This dissertation presents a novel approach for seismic fragility analysis of single-layer reticulated domes based on Open Sees for the first time. An overview of work contained within this dissertation is illustrated below.1 The finite-element models of single-layer reticulated domes on Open Sees are built for the first time. A single-layer reticulated dome subjected to static load and earthquake is modeled in Open Sees and benchmarked against same models produced in SAP200 and Abaqus. Results highlight that the Open Sees model produces very similar responses compared to the well-established SAP2000 and Abaqus models, therefore Open Sees is considered suitable for seismic fragility analysis of single-layer reticulated domes.2 The theory and procedures of seismic fragility analysis of single-layer reticulated domes are introduced, and the overall-load-range dynamic response analysis has been implemented into an in-house developed MATLAB program. The influence of data fitting methods is also studied and results suggest that a linear regression is better than a polynomial regression for seismic fragility analysis and a minimum of 40 realizations is recommended.3 Effects of height-to-span ratio, load level and span are studied using the current seismic fragility analysis models. Results suggest that height-to-span ratio has relatively minor influence on the seismic fragility, and a height-to-span ratio of 1/5 offers the best performance. Load level is a very significant variable and the damage probabilities increase with load level at constant earthquake intensity level. Span is also a significant variable and damage probabilities increase with span at constant earthquake intensity level.4 The finite-element models of supporting structures–domes coupling systems are built in Open Sees, and the effects of rigidity of supporting systems on the seismic fragility of two coupling systems are researched. The results suggest that, the rigidity of supporting systems matters much in the seismic fragility of single-layer reticulated domes. Supporting structures with weak rigidity can reduce the damage probabilities significantly. With the increase of rigidity of supporting structures, the damage probabilities of different levels first increase and then drop again at constant earthquake intensity level. In design of engineering project, the supporting structures–domes coupling systems should be analyzed altogether to make sure the safety.