Replacement of the Reuss road bridge (Ottenbach)

Author: Diego Cedeno
Language: German

Abstract

The existing Reuss Bridge in Ottenbach is a prestressed concrete structure built in 1955 that connects the cantons of Zurich and Aargau across the Reuss river. After 70 years in service, the bridge no longer complies with current standards for traffic loads (SIA 261:2020), prompting the need for a replacement solution. This project aims to develop a preliminary design for a new bridge, providing a technically and economically viable alternative to the rehabilitation of the existing structure.

The proposed bridge concept consists of a continuous three-span steel-concrete composite structure supported on the existing piers. The superstructure consists of a reinforced concrete deck slab supported by twin weathering-steel plate girders. Partial demolition and reconstruction works are foreseen at the abutments and pier heads to ensure a functional and structurally sound connection with the new superstructure. The bridge ends are designed as semi-integral, featuring a continuous deck slab (without expansion joints) and longitudinal girders supported by bearings.

The new bridge will be constructed in successive phases. First, the steel girders are assembled and installed in three segments using mobile cranes. Once in place, the reinforced concrete deck slab is cast in situ in multiple concreting stages. Conventional formwork is fixed directly to the steel girders.

The total project cost is estimated at approximately CHF 3.7 million. This figure includes the construction costs of the bridge, planning, site supervision, and the legally required 7.7% value-added tax.

The chosen bridge concept reflects a minimal-impact design approach, structurally and visually aligned with the existing context. Its classical form and clean lines ensure functional integration and architectural continuity. In future project stages, an iterative process will allow the design to be refined by adjusting component dimensions and the construction process, resulting in an optimised final configuration for the replacement bridge.