A LARGE UNDERTAKING.

Otago Daily Times, Issue 13985, 19 August 1907, Page 3 (Supplement)

A LARGE UNDERTAKING.

THE GRAFTON BRIDGE. •• AUCKLAND, July 31. - The Grafton bridge, the contract tertii for which w two years, and which is to bo built of fcrro-concretlj, will have the greatest single s'paii; in tiio world, and in engineering and architectural circles iU construction will bo looked forward id with interest. Residents of solitliem cities can scarcely, realise how far behind the. time Auckland really is in many respects. The great distrid of Grafton, one of the faehioridblo residential, areas, would be 10 lriiiiutes' walk hi a straight lino, but owing. to tlio Cemetery Gully it is a good half-hour's walk; TJie ..Grafton bridge; which is to span this gully, will ccst £40,000 and absorb' 1400 tons, of cement. The main arch will bo the.crowning feature.of the structure, and will bo visible from North Shore across Waitemata Harbour. The span of the main (troll is, 32'0ff, arid for length,is not cqualle<l by any masonry work in the world. Tlio nearest span to it is on a bridge at Planon (Sajtbny), with a length of 295 ft, arid another notable bridge is near the River Isar, in Bavaria,' whero . there are two arches each 215 ft long. The local structure will have minor decorative arches; designed to roliefo the plainness; after the style of tlio old Roman aqueducts. The main arch lakes a very wido sweep, nearly completing a semicircle; as' will bo understood whcii it is mentioned that while the width, is 320 ft tho depth is over 100 ft. At both ends between the aroh and tile approaches arb two heavy and stately piets, treated so as to adiieve tho desired architectural .effect- Then two approaches at either end take the shape of straight, girders, carried oil. plain piers. Front the Symdnds jtrcet sido the approach contains twd spans of 35ft..,each. and, four spans' of 70fl. each,, aiid is 200 ft longer tlidn the approach on the Grafton road side; which contains two spans bf 75ft each. 1 Tlio height of the piers will vary according to tho descent of the gully, biit all go 'down fo a rock .foundation, which iri eoine cases can only bo secured by excavating to a depth, of 40ft.. The total length bf tho bridge will be _910 ft and the height from the top of the roadway to the deepest part of the guiy 147 ft. Abalustrodbig sft high has betii prdvideel,.fbf .tlio full length of the striictliTe. As IKb carriageway between the kerbs is 24ft wide, .th'ere will be araplo rboiii for three lines of traffic; .and; .in addition, there are, two sidewalks 6ft wido for pedestrians. The whole structure will be built entirely of concrete, arid is calculated to absorb no less than IMO tons of cement, besides many thousand feet b[ steel for rein ; forcemerii purposes.