| 摘要 |
In pulling or pushing steel tendons, such as strands of steel wire through ducts positioned in a concrete structural member, the ducts are sheathing tubes encased in the concrete of the structural member. To limit the friction acting on the tendon as it is displaced through a duct, forces acting in the axial direction of the duct or vibrations acting transversely of the axial direction of the duct are applied directly to the tendon. These forces are applied at recesses in the structural member accessible at its outside surface. The friction acting on the tendon is compensated by the axially directed forces and the application of vibrations greatly reduces the coefficient of friction. These forces acting on the tendon can be combined and are particularly useful for moving tendons around small radius curves and through large redirecting angles. |
