Letter from the Secretary of war in response to Senate resolution of December 10, 1894, transmitting the report of the Board of Engineers and bridge-b . here, although the effect of the stretching of thosuspenders is illustrated at tho end of this appendix, but it may bo stated that theresultant effect is to confer upon the cable an increased facility of adjustment inform to tho requirements of avarying moving load, and hence, an enhanced capac-ity to receive such moving load directly through the suspenders withoutaction of the truss. The variations from tho exact treatment which involves thoc
Letter from the Secretary of war in response to Senate resolution of December 10, 1894, transmitting the report of the Board of Engineers and bridge-b . here, although the effect of the stretching of thosuspenders is illustrated at tho end of this appendix, but it may bo stated that theresultant effect is to confer upon the cable an increased facility of adjustment inform to tho requirements of avarying moving load, and hence, an enhanced capac-ity to receive such moving load directly through the suspenders withoutaction of the truss. The variations from tho exact treatment which involves thoconsideration of plastic deformation of tho members named results in formulaewhich, as the mathematical theory of tho combined elastic action of cables andbeams show, give greater bendingmoments and shears in the stiffening truss overthe greater part of the span than those which actually exist. All estimates ofmaterial for tho members affected will consequently bo on the safe side. Theinfluence of the elevation or depression of the cablo as a whole, due either to avariation in temperature or to elastic extension, is eliminated by the center The moving load will be taken on the left half truss A C, and the same notationas that given below fig. 1 in tho preceding section will bo used. Case I. In this case tho moving load w will bo taken as passing on tho truss from A andits variable length measured from that point will be represented by x\. Inasmuch as the pull exerted on the truss by the suspenders is upward and as thereis no moving load on B C, it is clear that the reaction R1 at B must bo downward indirection and that an equal downward reaction must bo exerted by the half truss ACouBC at C, the hinge point at tho center of the span. That downward reactionat C is a part of the requisite portion of tho moving load w X\ determined by the simple principle of the lever applied toAC= s as a span, while tho other part of 84 BRIDGE ACROSS THE HUDSON RIVER. that portion is carri
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Keywords: ., bookcentury1800, bookdecade1890, bookpublisherwashi, bookyear1894
