Concrete Shell Roofs Research Articles

Free Vibration Characteristics of Shell Roofs

The equation of motion of cylindrical shells is written using Donnell-Karman-Jenkins (DKJ) theory; and a Levy-type solution is used for computing their natural frequencies and model shapes. The method is applicable to shells simply supported on rigid traverses on the curved edges which have arbitrary support conditions along the longitudinal edges. Five cases of characteristic roots arise depending on the value of the natural frequency. Complete expressions for forces and displacements are presented for all the cases. The method has been used to compute the natural frequencies of a shell simply supported on all edges. Values are obtained that are identical with those obtained by the Navier type solution. A shell with edge beams has been analyzed. Its frequencies observed on a reinforced concrete shell roof model have been compared with theoretical values and found to agree closely.

2029 逆型円筒殼の応力解析(構造)

2029 逆型円筒殼の応力解析(構造)

THE MINIMUM WEIGHT DESIGN OF CLOSED SHELLS OF REVOLUTION

If bending stresses are negligible and clastic instability effects are absent the minimum weight concrete shell roof to cover a given circular area, carrying only its own weight, is shown to be a constant thickness dome, designed so that the meridional compressive stress is constant. The detailed shape is given, and the minimum weight proposition is restated to overcome the difficulty of ensuring only membrane stresses in the extremely flat shell designs which would otherwise result. The displacements are calculated, on the basis of perfect elasticity, and from them the bending strains, which are shown to be negligible for any normal shell roof. Some additional information is given on shells carrying a uniformly distributed load in addition to self-weight, but the minimum weight design is not established.

2030 逆型円筒殼の実験(構造)

2030 逆型円筒殼の実験(構造)

Ultimate strength theory for short reinforced concrete cylindrical shell roofs

Summary The theory proposed by Professor Baker in Magazine of Concrete Research No.4, in which he provides a simple method for designing shell roofs including prestressed shells, is extended to include shells in which longitudinal slab bending is not negligible.

A plastic design theory for reinforced and prestressed concrete shell roofs

Summary: A theory is proposed which provides a simple method for designing shell roofs, including prestressed shells. This method takes into account the effect of the plasticity and cracking of the concrete as the ultimate load is approached. The theory considers two possible limits of shear stress distribution across a transverse section, and it is shown that the bending moment does not vary greatly between these limits. The theory is intended as a basis for experimental work which is to be carried out in the near future at Imperial College.

Cost of Long-Span Concrete Shell Roofs

Cost of Long-Span Concrete Shell Roofs

ABSTRACT. CONCRETE SHELL ROOFS WITH FLEXIBLE MOULDS.

Keywords CONCRETE, SHELLS, ROOFS, FLEXIBLE, MOULDS, SIMPLIFIED, CONSTRUCTION, METHODS, CORRUGATED, FABRICS, SCAFFOLDING, REINFORCEMENT... Show All