Summer Theatre

Montevideo, the capital city of Uruguay, has an open air Summer Theatre located at a public garden, Parque Rodَ, close to the shore of Rيo de la Plata river. The authorities of the City of Montevideo decided to replace the 45 years old metallic acoustic shell by a new shell of reinforced brick and requested our office to project a shell of about 600 m2, which should cover the stage of the theatre and should fit the existing colourful open tribune. It was designed as a conoidal vault of reinforced brick. In addition to self weight, wind pressure and other stresses, the vault should be able to bear hanging devices for illumination, acoustics, curtains, etc., totaling 72 tons. The ruled surfaced was generated by the movement of a straight line along two catenary arches. A finite element program was used for designing, which dealt with curves with different degrees of approximation to catenaries. A special formwork was projected, consisting of nine rows of steel towers that supported a wood and timber superstructure. Modular steel towers were designed to be reused in following works. The masonry consisted of hollow bricks (25 cm × 25 cm × 17 cm), manufactured in Montevideo. Steel bars were placed in the 2 cm thick joints between bricks and in the external mortar layer. In order to increase steel protection against corrosion, the mortar for the joints and for the external layer was designed with low water/cement ratio. Laying out the curved surface and positioning the joints on the formwork presented considerable difficulties. Organisation of labour force in two shifts with complementary tasks brought economical and time benefits. The project was prepared in 2006. The construction took 4 months, it finished in December 2006. This paper presents the process of design and construction of the shell.