Elevated way at Krahnenberg

Abstract

A bypass on the general highway is now being built near Andernach, Germany. It is about 1100 m long, and includes an elevated way. The design has been influenced by the poor soil resistance, and the fact that the road is built on a mountainside. The elevated way runs along a curve, with a minimum radius of 475 m, and is subdivided into 34 sections, each 31.75 m long. The deck consists of a box girder, separated into two compartments, and is of prestressed concrete. The deck cantilevers on each side of the longitudinal structure, and has a total width of 18.20 m. This allows for two separate pavements, a central separating section, and two lateral sidewalks. The construction procedure was significant. Owing to the nature of soil, and the need to avoid heavy concentrated loads, the traditional system of formwork was substituted by the Gerber procedure. This consists of 4 metal open girders which rest on the columns, which had been previously constructed. These beams, which are capable of conforming to the curvature of the road, are moved along the axis of the deck, with the aid of hydraulic jacks, as the process of concreting proceeds. A crane, with an operational reach of 35 m served to supply the materials and formwork at the various construction points.