REINFORCED CONCRETE

Evening Post, Volume CIV, Issue 46, 23 August 1922, Page 11

REINFORCED CONCRETE

TALLEST BUILDING IN 'AMERICA Aooordmr to "Oonorete," thsre ha* jntt been completed in New York an eifhteenRtory building in reinforced oonexete, and known as the ''Hide and Leather, Build-1 ing " This constitutes the tallest buildingof it* type in the United States of America, and provides a notable example of ooncrete both as a structural and architectural building material From basement floor' to roof the total height is 223 ft The building is square in plan of 75ft side, and is divided into bays each way of about 18ft square The whole structure, which includes a 10,000 gallon water tank on the roof embodies no structural steel or brick Situated on what is ' known as "The Swamp," its foundations are of especial interest Thess are of the "Protest" type selected as the only possible, in view of the fact that the bearing strata consisted of 100 ft ot sand of varying,' qualities underlyingstrata of muck and peat In this system sectional precast ooncrete piles are driven by hydraulio pressure as the building" progresses The piles are driven in in stages as the weight upon them increases, and only attain their final position when the frame of the building m oomplete I Thoir efficiency depends upon the "bulb of pressure" that is the portion of the strata which actually carried the load It is found that if points of equal pressure are joined the shape is (that of a bulb, the cohesion of the particles of the material of 1 which sustains the load It is known that piles which have successfully withstood certain test loads often settle whench much smaller loads are later applied Success depends t upon the maintenance of the bulb ones it is form To carry out the system shallow pits are excavated at the locations of walls and columns Cvhnders of steel1 casing sft lonp and 20m diameter are irrouried tin may be required by the final load and filled with concrete Tfcev are surmounted by wood blocks to 4;ho height of the under* vde of th 6 future concrete cap or column footing !Tbeso<capß are then placodi in position and the erection of trm biuMim* proceeded with, thus* savmir time while thf foundation* ere bemtr finished The cylinders are then jaclc«J down by hv rlraulic rams in successive staves as the building proceeds further sections of cas mcr and ooncrete beinir added to main tniin the oontmuity' of the pile Wtiw the pile has reached its final position* the pressure which is already upon it through ' a hydraulic ram is then transmitted through an, I beam cut to lenpth .and wedped';n between th# mle and the concrete cap This method »npea« to be the only one which "ould haro been adopted nnd the building, the first all concrete skyscraper, will probably be 1 forerunner of many more-of the same type ' '