Concrete cylindrical shell roofs prestressed within the shell surface.
Thesis DisciplineCivil Engineering
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
Cylindrical shells, constructed of precast concrete elements prestressed together by means of cables within the curved surface, are shown to have satisfactory and predictable behaviour under static load. By careful choice of prestressing layout, cracking can be delayed until a considerable surface load has been applied. An existing elastic analysis method for effects of prestress, based on the D.K.J. equation, is adapted to improve its accuracy and efficiency. A method is given for calculating the effect of the stiffness of the traverse on the distribution of anchorage force to the shell. This can be particularly important when the anchorage is placed close to the shell edge. Circular cylindrical shell roof models without edge beams and prestressed within the curved surface with both straight and draped cables were tested to failure. Four of the five shells were constructed from precast elements. Strain and deflection measurements were obtained for all shells and confirmed the reliability of the analysis method. A flexural beam type ultimate load analysis is devised which accurately predicts the ultimate loads of a range of shells including the model shells tested. This analysis is developed into a design technique. Some approximate methods are developed for the working load analysis of cylindrical shells prestressed within the shell surface.