Method and apparatus for pumping concrete to form structure at elevated

Abstract

A method and apparatus is disclosed for continuously pumping flowable concrete mix to elevated heights for introduction into forms used in the fabrication of annular structures such as concrete hyperbolic cooling towers. A tower crane is erected in the center of the circle for the hyperbolic structure and concrete conveying piping is provided for raising mix to a lateral conduit carried by a secondary boom suspended from the swingable overhead jib of the crane. A pumping unit at ground level forces concrete mix up the vertical piping on the tower and then through the boom supported conduit for delivery into the form structure. The jib and thereby the boom suspended therefrom are swingable through an arc of 180.degree. in one direction to cover one half of the form structure and then the jib and boom may be swung in the opposite direction through the remaining 180.degree. arc for introduction of mix into the form structure. The tower crane is of the type having a climbing cage permitting lifting of additional mast units to the top of the stack thereof using the jib as a lifting medium to increase the height of the crane. Corresponding pipe sections on the tower mast units allow delivery of concrete mix to increasingly higher elevations as fabrication of the hyperbolic structure progresses. The length of the secondary boom and thereby the laterally extending conduit supported thereby may be increased or decreased as necessary to accommodate the changing diameter of the hyperbolic concrete shell during construction.