Doctor of Philosophy
Civil and Environmental Engineering
El Damatty, Ashraf A.
Cable domes have been widely used in many architectural applications such as arenas, stadia, and religious facilities because of their light weight, attractive appearance, and adaptable forms. Yet, cable domes are very flexible and sensitive to wind loading. The main problem in traditional forms of cable domes with positive-Gaussian curvature is the potential instability under excessive loading due to slacking in cables and/or buckling in struts. This motived designers to develop new forms of cable domes with more stability and rigidity. The current study considers a new form of cable domes with double curvature (saddle-shaped dome) that is intended to have better stability and rigidity. However, its feasibility and stability need to be addressed before using it in practical applications. Moreover, accurate evaluation of wind pressure distribution on the roof is essential for understanding their aeroelastic behavior. A novel form-finding algorithm is introduced in this study utilizing NURBS curves to control the saddle surface curvature while searching for a feasible geometry and prestress distribution that gives the domes its stiffness before applying loads. A time-efficient optimization technique is then developed to optimize prestress level and cross sections to the minimum weight. The developed algorithms are employed to develop a large database of feasible and optimized domes considering different geometrical parameters. The database is employed to train surrogate functions that can be used by designers as a decision supporting tool in the preliminary design of double-curvature cable domes. The new form stability and rigidity under excessive loading is also investigated and compared with the traditional form with positive curvature. Finally, the wind-induced mean and peak pressure on double-curvature roofs are also reproduced using computational fluid dynamics simulations validated with wind-tunnel experiment considering a wide range of geometrical parameters. The adequacy of wind load provisions of Italian code for this new form with double curvature is also explored. The results demonstrated the capabilities of proposed algorithms in designing a feasible, more stable, and cost-minimized cable dome. The findings of this research are recommended to be considered when designing double curvature cable domes according to the current wind load provisions.
Summary for Lay Audience
Cable domes have been widely used in many architectural applications that require covering large areas without interior columns such as arenas, stadia, and religious facilities. They consist of cables and steel bars covered with light membrane. Their popularity arises from their light weight, attractive appearance, and adaptable forms. However, they are very flexible and sensitive to wind loading. The main problem in traditional forms of cable domes is the potential instability under excessive loading. A new saddle-shaped form has recently been developed in response to the demand for more stable, yet less costly cable domes. Before using this new form in practice, investigating its structural design as well as behavior under wind actions is required. This research proposes a new approach for designing a variety of geometries with the minimum weight. The stability and rigidity of selected geometries are studied and compared. The designed geometries are then incorporated in Artificial Intelligence-based models to provide designers with a fast simplified method that can be used as a decision supporting tool in the preliminary design of saddle-shaped cable domes. Finally, the wind pressure distribution on the roofs is simulated using numerical tools and compared to the current wind load provisions for similar topologies. The findings of this research show that the new form of cable domes is more stable and less costly than the traditional forms. Recommendations for designing saddle-shaped cable domes are also provided to compensate for the limited regulations in the current design codes.
Ahmed, Elshaimaa A., "Structural Optimization and Aerodynamic Behavior of Double-Curvature Cable Domes" (2024). Electronic Thesis and Dissertation Repository. 9898.
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Available for download on Friday, January 16, 2026