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THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[Feb. 24' 



CARRINGTON BRIDGE, NOTTINGHAM. 



(' JVith Engravings, Plate 2.) 



This bridge was erpcted from tho designs of H. M. Wood, Esq., 

 Architect to the Corporation of NoKinghLim, and subject to llie ap- 

 proval of Thomas WoodhoiiM', Esq., C. E. to tlie Midland Comities 

 Railway. It was built at IIih joint expense of the Corporation ot 

 Nottingham and the Midland Counties Railway Company, at a cost of 

 ie5,045/., and makes a new and beautiful approach to the Railway 

 Station. The iioveltv of this bridge eonsisis in the flatness of the 

 arch (the span being /"O feet and the versed sine only .i, which is less 

 than any iron bridge I am aware of,) it is also remarkable for having 

 ornamental scrolls for spandrils. The width of the roadway is .')0 feet. 

 The masonry and approache-j were executed by Mr. Henry Sharp, and 

 the ironwork by Messrs. Cort and Co., ironfounders, &c., of Notting- 

 ham, and Leicester, and tlie work was completed in the most substan- 

 tial and durable manner. The quantity of cast iron used in the course 

 of erection amounted to I'll! tons, and the wrought iron, including 

 bolt and tension rods, about 1,568 lb. 



This bridge now forms a very pleasing object, and is one of the 

 principal ornaments to the interesting town of Nottingham, and does 

 equal credit to the public spirit of the inhabitants, the talent of the 

 architect and the skill and enterprise of the contractors. 



The bridge was commenced in the early part of 1842, and com- 

 pleted the same year, and much to the credit of those that were 

 employed, not the slightest accident occurred during the progress 

 of thu works, not even so much as fracturing a stone or breaking 

 a rope. After proper scaffolding had been thrown across the 

 canal from abutment to abutment (under which the boats contain- 

 ing the ril)s were brought), with necessary hoisting tackle, and a crab 

 on each abutment, the whole of the ribs were hoisted into their places 

 in 15 days. An attempt was made to test the ribs in the foundry 

 yard, but in consequence of the difficulty in procuring suitable abutting 

 places to carry the heavy weights intended to be applied, and the 

 probability that they would not be fairly proved, it was abandoned, 

 and they were afterwards tested in their places at the bridge in pairs, 

 the weight consisting of pig lead, equally distributed over the whole 

 length of the ribs, and the following is the result : — 



Weight ai!|ilie<i. Dfllexioil. 



1st pair .. 5*1 tons .. s 



2d „ .. SO „ .. I 



^ 3d „ .. 80 „ .. I 



% 4th „ . - 80 „ . . 1 



5tk „ .. 80 „ . 14 



No peimailent set of any consequence was perceptible after the 

 ■weight wasiwithdrawn. Before the experiment, the ribs were securely 

 wedged iri their places, as shown in the drawings, and no evil effect 

 appe;irs to have arisen since the completion of the bridge from the 

 expansion anAcoutraction of the metal, as assumed by some engineers, 

 nnd foT whicbthey make allowance in their works. 



To form the roadway, Jlemel planks 4in. thick were bolted to the 

 ribs, this is, in my opinion, the only defect in the design of the bridge, 

 as in works of tiri9''natt)re iniperishable materials only should be used, 

 covering |>lat'es of cast iron should have been substituted, which, 

 althougli More expensive in the lirst instance, would have been the 

 cheapest in tin; end, as timber in such a situation cannot be calculated 

 to eTidiire more tlian 20 years. The joinls of the planks having been 

 properly caulked, a layer of tar and pitch of equal parts mixed with 

 sand, in proportion of half a peck of sand to nine gallons of tar and 

 pilch, was applieil.in a hot and fluid state three quarters of an inch 

 thick, w hicli^made d covering' impervions to moisture. The roadway 

 was formed of MoiVut»"Sorirfel granite, with which was mixed a small 

 portion of tar and pitch, \nd from the adhesive nature of the resinous 

 matter, with tlie assistance of a roller, it readily consolidated and formed 

 u compact mass. Roads or streets composed of this material make a 

 very smooth and pleasant surface lo travel over; it forms a very hard 

 road, is perfectly clean in the winter, as the subsoil cannot work 

 through it, and is free from dust in summer, an advantage of which 

 no other road material, that I am aware of, can boast. 



Iron as a material for bridges is growing more extensively into use, 

 and its superiority over other materials, as to durability, facility of 

 construction, and its capability of being moulded to any pattern, so as 

 to form highly ornamental structures, becomes daily more evident; 

 and its uion- gemral introduction in puljlic buildings, manufactories, 

 &c., would be of great utility. 



The details of construction will be sufficiently understood by a re- 

 ference to the engravings. 



Refekence to Engraving, Plate II. 



Fig. 1. Elevation of bridge; scale lin. to 20ft. Fig. 2. Half ele- 

 vation of external rib, cornice and railing. Fig. 3. Ditto of inner 

 rib ; scale -f^ i". to 1 ft. 



Fig. 4. Plan of ribs and braces; scale -'^ in. to 1ft. 



The scale of the following figures is n in. to 1 ft. 



Fig. 5. Section tlirough external rib. Fig. G. Section through ex- 

 ternal rib and cornice A to B. Fig. 7. Section through inside rib, 

 A to B, 211. Sin. from centre to outward. Fig. 8. Back of plinth. Fig. '.I. 

 Transverse section of stay from E to F on Fig. 4. Fig. 10. Section 

 from L to M of ribs. Fig. 11. Section from G to H of ribs. Fig 12. 

 Plan of abutment jilate. Fig. 13. Section of ditto from X to Y. 

 Fig. 11. Transverse section of abutment plate of quoin from V to W. 

 Fig. 16. Section of bracing frame from C to D on Fig. 4. Fig. 16. 



Transverse stay. „ „ „ ^ 



B. B., C.E.,&Cy. S. 



TUBULAR BOILERS. 

 (IVilh Engravings, Fig. 1 to 4, Plate 3.) 



It is our intention occasionally to give drawings founded upon the 

 most approved mode of construction, of marine engines and boilers; 

 we now commence with a tubular boiler for 60 h.p., and shall hereafter 

 give designs for one of 150 H.P., and afterwards of 300 h.p., up to 

 500 H.p. . , 



The drawings represent a tubular boiler, of the most improved 

 construction, as used on board our fast river steamers, and now in- 

 troduced into the vessels of Her Majesty's navy. The power is of 

 (iO horses, say two marine engines of 30 H.P., or 3ft. stroke, and 

 3U in. cylinders, making 30 strokes per minute. It may be manufac- 

 tured in one piece, and with its apparatus complete, would weigh not 

 more than 10 tons, a manifest improvement on the old system o^ flue 

 boilers, which, for the same power, could not be made of less weight 

 than 16 to 17 tons, and occupying, superficially, a space of 14 ft. 

 square. The weight on the safety valve may be 10 lb. per square inch. 

 The steam expanding in the cylinder at one-third of the stroke. It 

 wonld easily perform this duty, with a moderate consumption of fuel. 



The suif.ice, and detail of construction, are as follows:— There are 

 six rows of tubes of I'J each, or 114 in all: they are 21 in. diam. in- 

 side and about 3 in. outside. The superficial area will be 2 J diani. — 

 5-'j4 area X 1 H tubes = 677 square inches total sectional area of 

 tubes. 



The surface of tubes 



65007 



144 



= 45 1-4 sq.ft. 



148-8 



23diain. = S-64cir. X 66 in. long X 114 tubes: 



Plate surface. Fires (above grate) and uptakes 



Total absorbent surface of boiler . . . . 600-0 



Grate bar surface 7-0 X 2-1 X 3 fires = 43'9 square feet. 



Area of grate uptake = 12 in. by 75 in. = 900 square inches. 



Area of tubes (as ibove) .. = 677 ditto. 



Area of chimney uptake 14 in. X 48 in. = 672 ditto. 



Area of chimney = 24 in. diam. .. = 452 ditto. 



To be evaporated per hour = 74^ cubic feet of water, under 



juessure of 161b. per square inch. 



Results of surface, per nominal lioise. 



43*9 

 Grate bar surface = -^^^ = 07-25 square feel pel- horse. 



Tube surface 



Plate surface 



Total 10 square feet 

 Area of tubes 



60 



451- 

 60 



148'8 

 60 



= 7-5 ditto 

 = 2-5 ditto 

 10-0 



ditto 

 ditto 



677 



^ = 11-25 square inches per horse. 

 Ditto of grate uptake -^-—- = 15-00 ditto ditto 



Ditto of chimney ditto 

 Ditto of chimney 



11-20 ditto. 

 7-50 ditto 



ditto 

 ditto 



