The General Situation. The sructural steelwork trades and professions have probably felt the effect of the recent general business depression more than any of the other leading industries in this country. Harold V. Crabtree
Sir,-In the March number of the Institution's journal a letter appears under the signature of Mr. G. Robertson, asking for an amplification of the explanation given in reply to his query on the danger of the action of creep in portal frame bridges during the discussion of my paper on the Creep of Concrete under Load.
MAJOR DU PLAT TAYLOR (President., British Section, Sociee des Ingenieurs Civils de France), before proposing a vote of thanks to Mr. Gueritte, said that it was a great pleasure to the members of the British Section to come and join in the meeting of the Institution, and he hoped this system of exchange might long continue. It was a great pleasure to him also to propose a vote of thanks to his old friend, Mr. Gueritte, for a very interesting paper, on which he would like to make one or two remarks.
THIS scheme has been carried out by the L.M.S. Northern Counties Committee, in conjunction with the Government of Northern Ireland, to expedite the service to Derry and Portrush and relieve unemployment. It involves a new line about 28 miles long, which crosses several public roads and numerous streams. All bridges, both over and under, are carried out in reinforced concrete. At one point the existing railway crosses a deep glen by means of a 2-span masonry arch, but the new loop line crosses a tan angle about 200 ft.farther up stream, involving a viaduct structure about 630 ft. long. Immediately at the Belfast end of this structure the down line to Larne will pass underneath the new viaduct, and cross the glen on a line approximately parallel to the existing 2-span arch. This necessitated a second viaduct about 400 ft. long, which is known as the Down Shore Viaduct. (The up shore line is carried on the existing 2-span masonry arch.)
Although articles published in The Structural Engineer normally deal with large scale engineering, it is thought that a brief account of certain R.C.C. work carried out during recent operations on the North West Frontier of India, may be of interest its comparative insignificance being perhaps somewhat atoned for by the fact that difficulties inherent in active service conditions give even small engineering tasks a distinctive character. J.W. Hay
In all the structures with which it is proposed to deal it is assumed that the displacements caused by the application of loads are so small that in calculating the forces in the various parts of the structure its initial form may be assumed. In most structures this may be done without appreciable error and, as a consequence, we may express any static function H, such as a reaction R, a force S, a bending moment M, a shearing force Q, deflexion... H.A. Whitaker