SCIENTIFIC AMERICAN ESTABLISHED 1845 NEW YORK SATURDAY SEPTEMBER 3 1904. the history of the city's abortive attempt to build a suspension bridge across the East River at a point adjacent to the present Brooklyn Bridge; and we think that the average citizen of New York would have found that story positively entertaining had it not been so completely humiliating to his civic pride. In illustrations of the substitute plans which are pro posed by the present Bridge Commissioner. no attempt was made to criticize the engineering features of these plans and this not for the reason that they were by any means beyond criticism but because we felt that the time was not then ripe for such discussion. Judged purely from the msthetic standpoint the new design if we except the anchorages is pleas ing particularly as comparA with the recently completed Williamsburg Bridge. The improvement is due to the very shallow depth of the stiffen ing truss which runs at the floor level from end design what it gains in appearance from this shallow truss it loses in structural efficiency. The object of such a truss is to prevent local sagging of the cables under a concentration of load at any point in the bridge where it may occur; but the ability of a truss to resist this bending is proportionate to its the cube of its depth. Hence other things being equal the shallow truss such as here proposed will be a weak truss unless indeed it be made extraordinarily heavy and an immense amount of steel material be massed into the upper and lower lines of the trusses or what are technically known as the top and bottom chords. But if such a massing of material be made in order to com pensate for weakness due to shallow depth the truss the increased weight of the trusses; consequently the bridge becomes proportionately heavy and costly. Now this decreased strength and stiffness or greatly inareased weight anl cost as the case may be does not appear in such a dainty little drawing of the bridge as was show
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