50 YEARS' SERVICE

Wanganui Chronicle, Volume 75, Issue 180, 2 August 1932, Page 6

50 YEARS' SERVICE

PATEA RAILWAY BRIDGE. NEW STRUCTURE DESCRIBED This week the last of a 50-year-old railway bridge north of Patea will be removed. It has been replaced with a new structure which has been in use since June 2. The old bridge was opened in 1881, which would place its building in .1880. In 18.6 the trusses were renewed with ironbark. Built of steel and concrete, the new bridge comprises three spans, a central 120 foot steel truss and two 60-foot spans at either end. Considerable difficulty was experienced with the foundations owing to the depth of the mud and silt on the river bottom. Two piers in the middle of the river are of the cylinder type, constructed of concrete, and are sunk 63 feet below rail level. Each has a cluster of ironbark piles in the bottom, making the bottom of the foundations 105 feet below rail level. The two abutments are supported on concrete piles. On the southern side the driving was very soft, necessitating splicing of 30-foot ironbark piles into the 40-fo3t concrete piles. This is described as a somewhat unique method of obtaining the required bearing to carry the load. The provision of the temporary work was found to be a job of some magnitude and for that purpose 75 foot and 80 foot piles had to be driven. Foundations were put in by contract. All the steel-work was manufactured in the department’s own workshops and was erected by the department's staff. The bridge was tested -with two Ab. engines and found satisfactory on June 26, since when it has been used for traffic.