The doctoral thesis of the student Aqeel Muhammad Hammoud from the University of Basra, College of Engineering, Department of Civil Engineering, entitled Seismic Analysis of Reinforced Concrete Shell Roofs, was discussed. The thesis included: the forces resulting from these seismic loads are enough to cause high stresses that are beyond the strength of the shell, causing cracks to form or the parts of the shell to break apart. When these stresses occur, the shell will often break apart or crack. Most of the cases, the concrete shells were highly durable in their resistance to earthquakes due to the nature of their curved shape and lightweight, which gives them great stiffness and stability. It was found that the finite element method would be the most effective way to study this problem.
Eight types of reinforced concrete shells were studied, including short, medium, and long cylindrical shells, double curvature shells, concrete domes, conical domes, hyperbolic paraboloid shells, and finally folded plates. These concrete shells are exposed to the Landers and El Centro earthquakes, and concrete shells have been compared with their response to the Halabja earthquake that occurred in Iraq in 2017.
Where the results showed that the long cylindrical concrete shells are highly responsive to the deformations and stress exerted on them by the earthquakes affecting them. The least effect of these earthquakes was in the double-curved shells and domes, as well as in the conical domes. Knowing that the effect of the Landers earthquake is the most effective in most of the cases used, and the least is the effect of the Halabja earthquake. Since the stresses exerted by earthquakes and self-weight are relatively low. in most cases, rebar is required at a minimum, due to the requirements of thermal shrinkage and expansion.
