4715 x 2196 px | 39,9 x 18,6 cm | 15,7 x 7,3 inches | 300dpi
Data acquisizione:
8 agosto 2001
Ubicazione:
Dumfries, Scotland, UK
Altre informazioni:
Questa immagine potrebbe avere delle imperfezioni perché è storica o di reportage.
A beam bridge is a rigid horizontal structure that rests on two abutments at either end and may be supported by additional piers along its length. Steel is an important component of many bridges because it is lighter than reinforced concrete, can be fabricated off-site and lifted into position by crane. The drawback with steel beams is severe corrosion that, if untreated, will eventually cause the failure of the structure. Untreated steel must be regularly maintained and painted which can be very costly and difficult. Since the 1960s, following its introduction by the military and the rail industry, special weathered steel has been available to engineers that develops its own protection against corrosion. With repeated wet-dry rain cycles, the steel eventually gains an impenetrable and stable brown-black patina that is impervious to further corrosion, self-heals if damaged and needs no further maintenance. Unfortunately, weathered steel cannot be used in salt-laden coastal regions or on highways where de-icing salts are used because the salts attack the steel but, otherwise, the material has considerable economic and environmental advantages.
