Browsing by Author "Volkmann, Janeke Franziska"
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- ItemImplementation of the Fire Beam Element (FBE) in OpenSees for the analysis of structures in fire(Stellenbosch : Stellenbosch University, 2018-12) Volkmann, Janeke Franziska; Walls, Richard Shaun; Stellenbosch University. Faculty of Science. Dept. of Civil Engineering.ENGLISH ABSTRACT: Fire safety design for buildings has become an increasing concern worldwide, especially after disasters such as the World Trade Centre collapse and the more recent Grenfell Tower re. In such cases, structural re engineering plays a crucial role in the inherent re resistance of a structure. Traditionally, prescriptive methods were used to achieve re resistance. These methods, however, are largely based on singleelement tests in a standard re and therefore do not consider critical global building behaviour. Consequently, performance-based design methods are becoming accepted as the more scienti c approach to the design of structures in re. The Fire Beam Element (FBE) method is such a performance-based approach that simpli es a structure into a skeletal frame consisting of only beam and column elements. The work in this thesis employed the FBE method, modelled it in the OpenSees software environment, and subsequently applied it the context of global structures with restraint. To validate the developed model, benchmark case studies were sourced from literature and conducted in order to ensure that the model behaved accordingly. These case studies comprised a steel beam with high axial and bending forces, two simplysupported composite beams and a 2D steel frame, respectively. The second case study con rmed that even composite cross-sections can be modelled using a single beam element the model produced results similar to that of more a complex 3D shell model. The nal case study demonstrated that complex behaviour such as non-linear heating, restraint and buckling were captured by the model the latter two phenomena have not been considered in previous FBE work. A sensitivity analysis of the FBE model found that the e ect of increasing the mesh size of a cross-section does not increase the computational run time exponentially, thereby illustrating the developed models ability to handle more complex analyses. Furthermore, the e ciency of the FBE model allowed for a temperature sensitivity study to be conducted, and as temperature changes have signi cant e ect on structural behaviour, this would potentially be useful in design. In future, if the FBE method is developed in 3D, it could be linked to the Slab Panel Method, and presented as a possible analysis tool for structural re design of entire buildings.