The extensive application of building information modeling (BIM) technology has brought opportunities and challenges to safety risk management in the field of prefabricated building construction. It is of great significance to provide timely information and knowledge for safety risk decisions in prefabricated building construction, and to display this information visually. In response, based on the ontology theory and using the Revit software, in this study we aimed to establish a monitoring system for the construction of prefabricated buildings, which was verified through a practical case. The results revealed that, first, ontology technology can be applied in the Revit software through plug-in integration, and knowledge regarding construction safety risk management in prefabricated building construction can be shared, reused, and accumulated using this system. Second, problems with the design and construction models of prefabricated buildings that do not meet the specification requirements can be detected by the monitoring system in the Revit software. Third, automatic risk identification and response methods using ontology theory and BIM technologies can effectively promote construction safety risk management performance in relation to prefabricated buildings. These findings examine the application of ontology to the field of prefabricated construction safety risk management for the first time, enrich the research on ontology technology, and contribute to safety risk management in the construction of prefabricated buildings.

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This paper is intended for bifurcation analysis of a nonlinear tractor semi-trailer vehicle model in planar motion and for investigating its stability under constant running conditions. Bifurcation analysis shows that bifurcation diagrams of a tractor semi-trailer are quite different from those of a single-unit vehicle. Some instability phenomena of the vehicle system such as jackknifing, sideslip, and spinning are explained by correlating them with the behaviour in the neighbourhood of unstable fixed points based on analysis of eigenvectors, phase trajectories, and status of lateral tyre force saturation. It is also found that yaw planar instability of a tractor semi-trailer is caused by lateral tyre force saturation of the tractor's rear axles and/or the trailer's axles. Moreover, the stability region in the state space is demarcated, and a stability index for evaluating size of the stability region in a feasible domain is proposed. Yaw stability under constant driving conditions is analysed by using the proposed stability index.

Project schedule management is an important part of prefabricated construction project management. General contracting is an effective way to promote the development of prefabricated construction. However, at present, from the perspective of general contracting, the risk factors affecting the project progress of prefabricated buildings are not clear, and the relationship between risks is not known. The purpose of this study is to study the composition, hierarchical structure and transmission path of schedule risk factors of prefabricated construction in general contracting mode, so as to help the general contractor formulate effective schedule risk avoidance measures. This study uses grounded theory to obtain 22 risk factors that affect the progress of assembly building projects, and the data are from expert interviews. Using Delphi method and interpretative structural modeling (ISM), these factors are divided into seven levels, and the ISM model of schedule risk factors is constructed. The research shows that there are 60 progress risk transmission paths, and four progress risk transfer chains are obtained. This paper also further analyzes and puts forward suggestions to avoid risks for each level. Doi: 10.28991/CEJ-2022-08-01-010 Full Text: PDF