WORLD’S BIGGEST BRIDGE

Taranaki Daily News, 4 January 1929, Page 9

WORLD’S BIGGEST BRIDGE

HUDSON RIVER STRUCTURE

SOME ASTONISHING COMPARISONS.

THE LARGEST SPAN 3500 FEET.

Of 3500 feet, which xs of the longest suspension bridg . d istimr The bridge is being designs and constructed under tile directi ™ ° O. H. Ammann, chief engineer of bnd o of the Port of New York Authorivy, a Cass Gilbert, architect. Some layfflfen have; questioned the feasibility of constructing such a Io » bridge. Mr. Ammann in his first pio gresf report on the Hudson River bridge says: “Engineers familiar with the con struction of large bridges have P olllt^ d out from time to time that the ieasi bility of the building of as long a span as 3500 feet and more is essentially a question of economy, and that the span length and size of a bridge have nothing whatever to do with its safety, either during erection or after completion. The feasible limit of span is reached when the amount of metal required to carry a given load becomes excessive in cost, and not because the safety is impaired. The physical limit of span is reached when no. amount of metal, can safely carry more than its own weight. The latter limit can be mathematically determined for the safe strength of any given material, and has been calculated by various authorities at 10,000 feet or more.” The location of the JEludson River bridge is well suited to a suspension bridge on account of the high. land. on .both sides of the river at this point, which makes it possible to construct a bridge with comparatively short . approaches. The side spans of this bridge are 050 feet long and the total length, including the approaches, is 7800 .feet The width of the bridge floor is US feet, and there will be a central roadway 40 feet wide for four lanes of .traffic, two side roadways each 24 feet wide accommodating two lines of traffic, two foot walks each 11 feet 6 inches wide and a lower level for either four or six lines of rapid transit as the conditions require. The bridge floor will be supported by four wire cables each 36 inches in diameter. The cables will be supported by steel and masonry towers 210 feet by 65 feet at the base and 635 feet above the -water. Each of these towers would be as high as Paritutu, the central span would stretch from the New Plymouth Post Office to Eliot Street,' and the height of the roadway above the water would be about four times as high as the New Plymouth Post Office tower, while the total length, including the approaches, w/iuld stretch from Eliot Street to beyond Morley Street. These comparisons will give an idea of the vast size of the structure.

Realising the monumental size and the conspicuous location of this bridge, the Port of New York Authority is paying special attention to the architectural treatment of the entire structure and tlie approaches so that it will be handed down to posterity as one of the great monuments of the -world.