Robust Concrete Bridges without Bearings and Joints

Abstract

This paper presents design criteria for a more robust type of bridge, without bearings and joints. The conceptual design of the structure must be emphasised, to achieve greater efficiency and eliminate service-life problems. The guidelines of this approach include: (1) use of preventive measures to avoid unfavourable consequence; (2) early recognition of safety-relevant damage, to eliminate unforeseen failures; (3) 'friendly' reaction of structures to catastrophes; (4) slight deviations from calculations need not produce disproportionately large damage; and (5) restriction of the extent and intensity of scheduled effects, to achieve the planned service life of the structure and its essential parts with an appropriate amount of maintenance. Bearings and joints were first introduced in the mid-20th century, in reinforced concrete bridges, to reduce constraints and facilitate construction. They also resulted in modern concrete bridges having maintenance-weak points and an often unsatisfactory appearance. In comparison, monolithic structures have several advantages, and can be used as prototypes for robust concrete bridges. Their characteristics include: redundancy, compactness, stress-flow-oriented design, and replaceable elements. They are feasible today, and offer many ways of improving design and aesthetics.