NEW CITY BLOCK.

Auckland Star, Volume LXIX, Issue 128, 2 June 1938, Page 7

NEW CITY BLOCK.

MASSIVE FOUNDATION.

UNUSUAL CONSTRUCTION.

DEPARTMENTAL OFFICES. Mile upon mile of steel, tied together in a massive, immovable network and resting on unyielding concrete, gives an impression of immense strength in the foundations now being constructed for the Government's new eicht-storey departmental building in Jean Batten Place. For five months the work has been in progress, and to-day the huge raft-like structure on which the bigblock will rest is approaching the stage when it is possible to appreciate that this will be one of the strongest supports ever provided for an Auckland building.

Behind the hoardings which screen off the site from both Shortland Street and Fort Street the contractors have had to contend with many problems. When a beginning was made early last summer, heavy blocks of concrete were unearthed during the excavations, and had to be removed. Also, an underground stream was tapped, and water from the upper part of the city had to lie pumped into the city's drainage svstem.

As the first job in the construction, the site had to be covered with an , unbroken slab of reinforced concrete. 137 feet in length and from 54 feet to 01 feet in width. Thus the weight of the future building would be effectively distributed over the clay and pug of the old river bed and original foreshore of the harbour. Xext. It was necessary to surround the whole site with a steel fence driven down to the rock below.

Progress of Operations. Several of these operations are now proceeding side by side. The stream has been forced underground again by the I bed t>f concrete, and only seepage is now finding its way upwards. The steel work is being made ready for the pouring of many hundreds of tons of additional concrete, and the surrounding eteel fence is three-quarters completed. Driving ten of the sheet piles each day, to an average depth of 25 feet, the contractors are really building around the soft clay foundations a barrier against any future movement. By this method a heavy buiuling may b e erected on clay. sand, or similar shifty material with complete security. For the mathematically-minded, a few quantities may give a convincing idea of the size of the undertaking. In the excavations. 5000 cubic yards of mixed clay and rock were removed from the site. The structural steel to strengthen the concrete has a weight of 50 tons, and the surrounding fence will weigh a further 50 tons. In the hollow "raft" and the ground floor slab will be a total of 1900 cubic yards, or 2850 ton*, of concrete. So the aggregate weight of the foundations will be 3000 tons. At present the contractors are about ten days behind schedule, but it is expected progress will be more rapid now the initial diifficulties have been largely overcome. Probably the steel frame of the building will begin to j appear above the street level within three months, and the first floor level j will be reached towards the end <.f the 1 year. The work of adding the additional seven storeys and finishing the interiors and will be included in <i separate contract. „ It is unlikely that the ouildiug v. ill ' be completed and ready for .vcujtatkni until the end of 1»3!J or the beginning of 1940. The thoroughfare through .Tcaii Batten Place may be reopened l.efi.iv ,thc- actual completion, but it i> thought that tr;.flk- will have to be ■■whale) from the street until the liouv construction is iini.-Led. The for;ii.-:ii<-ii of a'roadway 2<ift wi.ie a.'.d :'■•■: ;.n i>- of Oft and Sft will t7i.ii rc>i ]: ■' μ-vit..; j weeks before t!i<- imiilir i> :i-.i!;i i!!>'wi'l l to use this tliMiugii i r.-> ivtv <vu ii Shetland and K»:l >trc(-l>.