The Works Of Messrs. Schneider And Co.

LI. THE SCHNEIDER PAVILION AT THE PARIS EXHIBITION. MESSES. SCHNEIDER and CO.’S Pavilion is erected on the lef t bank of the Seine, below tlie Army and Navy building ; it is situated practically in a line with the Avenue de la Bourdonnais. The shape given to it is that of a huge dorne, crowned with a campanile ; it is 41 metres (134 ft.) in diameter, and the circumference is cut by a straight line at three places, where the main entrances are located. The portals which give on the Seine, and those opening to the Quay d’Orsay, being on a different level, the floor covered by the Pavilion, and on which the exhibits are placed, is formed of two levels, the upper one being 5.60 metres (18 ft. 4 in.) above the lower. The heiglits of varions parts of the Pavilion, above the floor level on the side of the Seine, are as follow : Height of the floor level on the Quai d’Orsay... ... ........ Height of ridge-piece of trusses......... ,, ridge of campanile 5.60 m. 32.64 m. 39.30 m. 18 ft. 4 in. 107 ft. 129 ft. the latter dimension being approximately the height of the Vendome Column. The outside covering of the Pavilion is formed of plaster made perf'ectly smooth ; that part of the roof around the base of the campanile is filled in with plate- glass ; the outside covering and the inside lining—the latter made of wood battens—are held by wood rafters in the usual way; the rafters are fixed to iron purlins, carried by the main ogee trusses. Two galleries, one inside the Pavilion and one outside, are placed around the whole circumference of the building ; they are 4.50 metres (14 ft. 9 in.) above the top platform. As will be seen from the section (Fig. 1055, Plate CLXIX), the Moulineaux Railway, in covered way, with brick walls and iron roof plates, passes through the build- ing. The walls forming the cutting existed previous to the designing of the Pavilion ; they could not be relied upon as supports for the beams inten ded to carry the enormous weights of the exhibits, nor of the lower parts of several trusses of the building. It was therefore necessary to build other walls parallel with those of the railway cutting, and this increased the spån of the beams to 17.20 metres (56 ft. 6 in.), a comparatively large spån. The beams are stayed directly below the foot of the trusses, in order to prevent the thrust causing any flexure of the beams in a horizontal plane ; besicles this, the flooring has been designed to withstand the shifting which the resulting force of the drift of the trusses it supports, tends to produce. This shows what minute précautions were necessary in the érection of a pavilion which rested both on recently built and comparatively high foundations, and on an iron flooring covering a railway cutting, and liable to be affected by the vibrations caused by the passing of the trains. As mentioned above, the double covering of the dorne is held by wood rafters and iron purlins ; the latter are placed about 3 metres (9 ft. 10 in.) apart, and follow the radius of the mean curve of the trusses ; their inclination, therefore, becomes greater accordine; as their distance from the ridge increases. This arrangement was necessary to facilitate the érection of the double covering. The purlins consist of ribs, made of plates and angles, in the shape of a double tee with unequal flanges, the web being in a line with the radius of the trusses ; they withstand, in con- séquence, the normal and tangential weight component forces. The trusses are twelve in number ; the twenty-four half ribs divide the dorne into as many equal sectors, 5.50 metres (18 ft.) wide at the base. Eighteen half trusses are ribs, the six half curved to the form shown in the illustrations, which serve as a support for the window bays, differ from the others only in the construction of their lower parts, which is made with an abutment. The system of construction is one with three hinges, and in order to fulfil in practice the theoretical conditions aimed at, i.e., that tlie trusses should be usefully hinged at top, it was necessary to make them converge over a sphere, instead of making them bear, according to the usual method, on a ridge ring. This is the first time, we believe, that this particular mode of construction has been adopted : for though the ribs, separately, are on the three-joint type, as a whole they meet exactly at top. This arrangement has the advantage that it aids the rapid distribution of the loads ; should some trusses beconie more loaded than others, the result woulcl be a displacement of the ridge joint, but this displacement would be counter- balanced by the action of the less loaded trusses. The ribs consist of a web 8 millimétrés (TViû.) thick ; and of four angles 70 by 70 by 8 millimétrés (2| in. by in. by TÇ in.), with flanges 270 millimétrés (lOf in.) wide, the thickness of which varies. The web is 750 milli- métrés (29-2-in.) high for the first sections, 1 metre (39| in.) at the spandril, and 600 millimétrés (23f in.) at the top. In a running truss, consisting of two similar half-ribs,