US71955A - charles bender - Google Patents

Description

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Be it known that I, CHARLES BENDER, of New York, in the county and State of New York, have invented.- a new and useful Improvement in Suspension-Bridges; and I do hereby declare that ,the following is a full` and exact description of the same, reference being had to the accompanying drawings, audto the letters of` reference marked thereon.'

Y My invention refers particularly to the dilferentspccies of stitfened suspension-bridges, and its 'nature consists, first, in dividing or separating the beams or trusses at one or more points, and connecting them by yielding joints; further, in the attachment of the chains or cables to the beams or trusses of the bridge itself, instead of fastening the same to abutments'; further, in the manner of securing the ends of the bridge to the end piers vertically, and in such a manner as to allow for the expansion and contraction of the bridge; and, lastly,in attaching the beams or trusses to the central piers sidewise, and fastening them, at the same time, at one pier in such a manner as to prevent any horiz'ontal movement in the direction ofthe longitudinalaxis .of the bridge.

Figure I represents a longitudinal elevation of my improved bridge. b y b The remaining figures represent details, showing the .separate parts on an enlarged scale, and will be more particularly referred to in the description. y

In thcaccompanying drawings, A represents the end or 'shore pier, and B B the central piers. C ai-e longitudinal trusses, constructed in the usual manner, subject to many variations, to correspond with thc style and nature of the bridge. D, in Fig. I, represents. the yielding joints, at the point where the beams or trusses are separated. One of the many possible plans of strengthening and stifening this part of thebeamscr trusses, and ofjoining the same together by means of a strong bolt, E, is represented in Figure II.` l l The object of providing one or more joints in the whole length of the beams or'trusses is to preventetlicreby any danger from the unequal expansion resulting from the different materials used in the construction of said beams or trusses, as well as of the cables or chains, further to facilitate thereby the bendingiof thebrdge by changes of temperature, to equalize any irregularity at the points of support of the structure'on the piers, and likewise to facilitate and rectify thereby considerably the analytical calculation of the whole structure. The manner of constructing this joint, as well as the manner of strengthening the adjoining ends of the beams or trusses, is subject to many variations, and has to correspond with the style and nature of the bridge. In Fig. I this joint is represented exactly in the centre, between `the central piers B and B', but the same may be placed in different positions, and may even be arranged at two or more4 places,'according to the nature `and to the number ofthe spans of the bridge, and may be used for all descriptions of stitl'en'ed suspension-bridges. l

Between the shore pier A and the first central pier B, strong diagonaltrusses F F, shown atan enlarged scale in Figure III, sheet 2, are arranged in the truss-work of the beams, having at their point ofjunction, near the middle of the height ofthe longitudinal beams or trusses, astrong bolt, G, around which the cables or chains II are fastened. These trusses F transfer equally the horizont-al forces of thecables or chains to the chords of the trusses, while strong uprights, J, resist theivertical pressure acting in the systemof the trusses F.

It is not essential by what arrangement of details `the strains ofthe cables or chains are transferred tothe chords of the trusses or to the beams. The only taski to be fulfilled is the equal distribution of said strains, and 'the annihilation ofthe different secondary forces; and this may be effected by various arrangements ofthe different partsin a suitable manner. y i A The exact position of 'thc attachment of thc `chains or cables to the beams `or trusses depends likewise on cireumstanceaand may be either nea-rer to or farther away from the shore pier A and, in some cases, it may even be advisablelto extend the beams or trusses beyond the said shore pierA, andplacc the point of attachment of the chains or cables beyond said shore pier. Mathematical and analytical examina-tion in cachsngle ease will determine the most proiitable-positionof these points. i

By this arrangement of attaching the cables or chains to the beams cr trusses, a great saving is in most eases obtained, as I dispense thereby with a great part of the expensive masonry at present necessary, at each end ofthe bridge, to secure the ends of the cables or chains. y l

'lhc cables or chains II are carried on the top ofthe central piers B audl, and tllcbeam's or trusses 'C are suspended from the same in the usual manner. Below the ends of the bridge, rollers K arelplaced, provided with side flanges x a', itting over the surfaces of the plates n andante prevent Lanyside motion me thhgivgcmw tbc ends. The plate n is securely fastened tothe under sident` thebeams orV trusses, and the plate m is attached to the top of the shore pier A. The ends of 'the bridge areat the same time fastened down by heavy bolts S, arranged on each side of the roller K. The lower ends of these bolts-S are securely fastened in the foundation of the piers, and are provided with suitable joints, v to allow for the-horizontal motion of the beams or trusses, resulting from expansion or contraction, in consequence oftliccbange of. temperature.

This vertical anchorage of the ends of the beams or trusses of stitcned suspensiombridges to the endor shore piers, or near the ends et' the bridge, prevents any upward movement ot the trusscnds, in case of any overloadingr in certain contingencies.

This arrangement of fastening down the ends of the bridge is represented at an enlarged scale in Figure IV, in front view and cross-section. 4

To prevent the undulatory motion causedv by the wind, as well as for other rcasonsfhereafter mentioned,ll attach the outer beams or the cords of the trusses et' the bridge to the central piers opposite the middle ofthe same. Projections L are securely attached te the outside-ot the beams orltrusses C, at the desired position, which enter into suitable guideframes N, fastened to the piers (s'eelFigureV) in such a manner aste brace thereby the bridge against the piQrSLsHVci-ent'play being nlloW'cd'f-inoncor more of the same to allow "for the expansion or contraction ofthe beams lengthwise. In the framesN'i'astened to the piers, suitable plates w are arranged, against which the projoctionsL,attached to the beams C, are made to bear, said plates w being capable of being regulated, by means of set-scrows a a. On that pier which is either in the middlc'of-the bridge, or on that next to its centre, I attach these be'amsin such a'manner as not to allow for ,any long'ltu ldinal motion, whereby the differences of the length of tbc bridge, causedrby changes of temperature, are regu* '-lated, and brought to a certainty, on either sid'e of this point oi" attncliment. By this attachment of the beams or trusses, sidewise to the piers, `the prcssurecaused by the wiudis'partly annihilated, the side motion of the same caused by the n'ind is considerably reduced, and the piers themselves are strengthened, the pressure resulting from thosev causes, and which in otherY cases is all4 on the top'ot` said piers, where the cables or chains are supported, is brought thereby lower doivn, 'or nearer. to its`lase.

What I claim as my invention, and'dcsire to secure by Letters Patent, is f 1. The construction and arrangement of one or more yielding` joints, connecting the beams or trusses of stiilencd suspension-bridges, substantially as herein described.

-2. I claim the attachment of ther-.ends of the cables or chains, at or near the iirst or shore piers, to the longitudinal beams or trussestof stiencd suspension-bridges, substantially as set forth;

3. I claim the means and method by which the ends of the beams or trusses of stiifened. suspensionbridg'es are secured to the shore piers by vertical anchorage, and the arrangement of suitable 4joints v in said anchors,

substantiallyfor the purpose described. i

1l. I claim the means and method employcdto rcducc the side mot-ion, by attaching the longitudinal beams or trusses of stiencd suspension-bridges to the centrehlcrs sidewisc, said attachment being on one pier per.

fectly immovable in. any horinontal direction, while at the otl1`e`r 'piers/allowance is made for the variations of the length ofthe beams, substantially as set forth and described. y

n Y i CHARLES BENDER. Witnesses s HENRY E. Rennen, WILLIAM Dnnrnn.,

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