. The Civil engineer and architect's journal, scientific and railway gazette. Architecture; Civil engineering; Science. two indefinitely thin flanges, but would be greatest in Ihe neighbonrhnod of Ihe vertical rib. Professor Moseley has throughout his investigation assumed that in the vertical section of a deflected beam the extension or compression is proportional to the distance from the neutral axis, and i' seems curious that he should have overlooked the fact that in a girder with wide flanges Ihe extension and compression of the flanges also would be, not uniform, but greatest in the neig
. The Civil engineer and architect's journal, scientific and railway gazette. Architecture; Civil engineering; Science. two indefinitely thin flanges, but would be greatest in Ihe neighbonrhnod of Ihe vertical rib. Professor Moseley has throughout his investigation assumed that in the vertical section of a deflected beam the extension or compression is proportional to the distance from the neutral axis, and i' seems curious that he should have overlooked the fact that in a girder with wide flanges Ihe extension and compression of the flanges also would be, not uniform, but greatest in the neighbourhood of the rib. M'ecomethen with the utmost security to this conclusion, that the strongest form of a beam is one in which Ihe material of Ihe flanges is collected as closely as possible to the upper and lower edges of the vertical rib. This form is very nearly approached in (he rails in most general use on our rail- ways, and may be easily imitated in the case of the Tubular Bridge. The accompanying diagram shows a section of the bridge with the principal portion of the material collected at the four angles. If we suppose these four masses to have circular sections, it is easy to calculate what diameter they must have in order to satisfy the conditions of the preceding investigation. It will be remembered that the sectional areas of the upper and lower plates were each taken at 18iJ square inches, and if the half of this area be as. signed to each side of the lube, the area of each of the circles represented in the diagram must be 90 square inches, and the diameter will consequently be about 10| inches. Let us take the diameter at one foot. Then the thickness of the solid masses at the angles will be equal to one-lhirlieth of the height of the bridge. These masses should not be united by continuous plates but braced together by a laltice of iron rods. There are many reasons for pre- ferring open lattice—they are chiefly these—superior sirength for equal weight of mat
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