International Historic Civil Engineering Landmark The Iron Bridge Built by the Coalbrookdale Company 1779 Presented on the bicentenary of the bridge

The Iron Bridge - Tontine Hill, Ironbridge, United Kingdom

Lake Pontchartrain Causeway Bridge. The original 23.86 mile-long structure, which now carries the Southbound traffic, was designed by the firm of Palmer & Baker. When opened in 1956, the structure was the longest bridge in the world by more than 15 miles. In building the bridge, which took just fourteen months, assembly-line, mass-production methods were utilized for the first time in the construction of a bridge. It was designed to employ hundreds of identical, hollow concrete pilings, concrete caps, and pre-stressed deck sections manufactured at an on-shore facility and barged into place. Engineering News-Record acclaimed the project to be "a bold venture requiring unusual foresight, ingenuity and resourcefulness." Opened: August 30, 1956.

Causeway Toll Plaza, Mandeville, LA, United States

Conwy tubular bridge Erected 1846-48. Original clear span 400ft. Strengthened by intermediate piers 1899 Engineers: R. Stephenson (1803-1859), W. Fairbairn (1789-1874), E. Hodgkinson (1789-1861). Architect: F. Thompson (1808-1895) contractor: John Evans. Built for the chester-holyhead railway, which provided rail access to the sea crossing to ireland, this bridge was a forerunner to Robert Stephenson’s Britannia bridge over the Menai Strait. Conwy tubular bridge was the first railway bridge in which trains ran through the main girders. It represents a pioneering use of wrought iron for bridges and a major advance in the development of box-section girder elements.

Castle St, Conwy, United Kingdom

Conwy Suspension bridge. Erected 1822-1826, span 327ft. Since replaced and strengthened with side trusses ---. Closed to vehicular traffic 1958 . Engineers T Telford (1822-34) and W A Provis ( 1822-50) . Ironwork W Hazledine, T Rhodes, --- T Wilson. This was the major structure on the strategically important Randor to Chester road. Conwy suspension bridge, Telford’s most dramatic creation in the gothic style was built with the identical technology developed for the larger Menai bridge (1818-26) and still has its original iron chains.

, Conwy, United Kingdom

Menai suspension bridge. Erected 1818-26. Height 153ft. Length 1388ft. Main span 580ft. Deck strengthened 1840 & 1893. Ironwork replaced by steel-work & deck modified & widened for modern traffic 1939-41. Engineers: T. Telford 1818-34, W.A. Provis 1818-50, Sir B. Baker 1893, Sir A. Gibb & Ptnrs 1939-41. Masonry: J. Wilson. This was the major structure on the strategic road connecting London with Holyhead and by sea to Ireland. The bridge with its then world’s longest span greatly advanced suspension bridge development. The smaller Conwy suspension bridge (1826) built with identical pioneering technology still has its original ironwork.

, Menai Bridge, United Kingdom