On Tubular Girder Bridges ...: With an Abstract of the Discussion Upon the Paper

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W. Clowes and sons, 1851 - Bridges - 56 pages
 

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Page 48 - That, as it has been shown that, to resist the effects of reiterated flexure, iron should scarcely be allowed to suffer a deflection equal to one third of its ultimate deflection, and since the deflection produced by a given load is increased by the effects of percussion, it is advisable that the greatest load in railway bridges should in no case exceed one sixth of the weight which would break the beam when laid on at rest in the centre.
Page 12 - And, in conclusion, considering that the attention of engineers has been sufficiently awakened to the necessity of providing a superabundant strength in railway structures, and also, considering the great importance of leaving the genius of scientific men unfettered for the...
Page 12 - London, 1849. :PucJun-5 _Strips superintendence of an engineer of admitted skill and extensive practice, was declared by one of the Inspecting Officers of the Railway Board, to be unfit for the public service, because it did not conform to the rules, which, in the Report of the Commissioners, were expressly declared to be applicable to cast iron only. The actual consequence of this decision, or rather of this application of an antiquated formula to a modern invention, was, that the public had already...
Page 11 - A society for the general advancement of Mechanical Science, and more particularly for promoting the acquisition of that species of knowledge which constitutes the profession of a Civil Engineer, being the art of directing the great sources of power in Nature for the use and convenience of man...
Page 55 - But in order that there may be no question as to the amount of load, it will be well to submit for the consideration of the Commissioners, similar results obtained with weights, concerning which no question can arise, as they can be made of loads in use at the present day upon railways in the kingdom, and may therefore reasonably be expected in the» course of the public traffic to come upon this bridge. " Weight of permanent load as reduced by Mr.
Page 12 - for the purpose of inquiring into the conditions to be observed by engineers in the application of iron in structures exposed to violent concussions and vibration.
Page 50 - ... he had reexamined the tubes with reference to their workmanship, and found he was fully borne out in the expression of a want of confidence in it, as the riveting was certainly very imperfect, and the joints were not accurately, or very judiciously made, and the top of the girders was considerably out of line, both horizontally and vertically, therefore in his opinion the opening of the line would be attended with danger " by reason of the insufficiency of the work.
Page 24 - If the continuous beam were hinged at the points of contrary flexure, and so divided into three independent beams, the previously existing conditions would remain unaltered. This being the case, it would be an evident error, if in calculating the strength of such a beam, AB only were taken as its length. In order to check, practically, the calculated position of the point of contrary flexure, the experiment was tried on a large wooden model, by loading it, first with such weights as represented the...
Page 56 - ACCIDENTS 101 possess ample strength, and all this in consequence of the attempt to introduce the system of centralisation and of Government supervision, which was found to be so pernicious in continental states, and the employment of officers who possessed undoubted skill for their own...
Page 26 - ... the deflection to the same amount as had, in the continuous beam, been produced by the weight representing 400 tons, and the proportion borne by the weight requisite to produce a given deflection in the detached beam, was to that requisite to produce the same deflection in the continuous beam as 65J to 120.

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