30-08-2017, 01:23 PM
Peels, taut skin structures due to their geometry and small stiffness of skin flexion, tend to carry loads mainly by direct stresses acting on their plane. Surface funicular concrete Rectangular plant shells, double curvature with different rises are loaded to failure with a concentrated central force. Specimens of size 100 cm x 90 cm in plan with edge beam of size 4cm x 4cm are prepared with grade M30 concrete for which the mixing design is carried out by the Indian Standard method. The specimens are prepared in various increments and are cured wet. They are subjected to final loads and the corresponding stains and deflections are measured. Fault patterns are observed for shells with different rises. From the experimental investigations we arrive at a relation between the relation of amplitude to elevation and the final load. It is concluded that the final loads are a function of the increase of the shell.
Structures can be classified in many ways according to their form, their function and the materials from which they are made. A structure or structural element may be a fully three-dimensional solid object such as a monolithic pyramid or may have some dimensions smaller than a ball bearing. The shells belong to the class of structures of stressed skin that, due to their geometry and small stiffness to the flexion of the skin, tend to load loads mainly by direct stresses that act in their plane. Shells impart force through their shape as opposed to force through the mass. Concrete shells are structures that by their shape offer an exceptional load capacity. Concrete shell structures are capable of spanning great distances with a minimum amount of material. Reinforced concrete shell structures are widely used because they provide exceptional performance and architectural beauty. Although it is an elementary structure in nature, much remains to be learned about its application in the construction industry. Ideally, a concrete shell in its membrane state withstands the external loads by pure compression, unaccompanied by shear stresses so that tensile stresses are not developed. It is advantageous to select the shape of the shell in such a way that, under the loading condition, the shell is subjected to pure compression without bending. This can be achieved by forming the wrapper in the form of a catenary whose funicular shape corresponds to the dead weight. Shell's rectangular and square ground plans are very prevalent in modern construction and architectural practice.
Structures can be classified in many ways according to their form, their function and the materials from which they are made. A structure or structural element may be a fully three-dimensional solid object such as a monolithic pyramid or may have some dimensions smaller than a ball bearing. The shells belong to the class of structures of stressed skin that, due to their geometry and small stiffness to the flexion of the skin, tend to load loads mainly by direct stresses that act in their plane. Shells impart force through their shape as opposed to force through the mass. Concrete shells are structures that by their shape offer an exceptional load capacity. Concrete shell structures are capable of spanning great distances with a minimum amount of material. Reinforced concrete shell structures are widely used because they provide exceptional performance and architectural beauty. Although it is an elementary structure in nature, much remains to be learned about its application in the construction industry. Ideally, a concrete shell in its membrane state withstands the external loads by pure compression, unaccompanied by shear stresses so that tensile stresses are not developed. It is advantageous to select the shape of the shell in such a way that, under the loading condition, the shell is subjected to pure compression without bending. This can be achieved by forming the wrapper in the form of a catenary whose funicular shape corresponds to the dead weight. Shell's rectangular and square ground plans are very prevalent in modern construction and architectural practice.