IRO

31

IRO

“ Upon each abutment is to be a springing plate of cast-•ron, each cast in one piece, and to have shoulderings andSockets to receive the ends of the ribs. Each plate is to be°f the form and dimensions as shown upon the drawings.The back of each socket, or the part against which the ends°f the ribs will abut, is to be clipped, and made to have a truea nd even face to the exact radius of the arch.

“ There is to be but 1 arch of 140 feet span, and rising14 feet; the arch is to be composed 'of 5 ribs, each cast7 pieces of equal lengths. The ribs are to be 36 inches*feep, in the direction of the radius, and of the exact shapeand dimensions as shown upon the drawings. The parts of®ach,rib and the ribs are to be connected by cast-iron tie orconnecting plates, each cast in one piece, and passing quiteacross the arch; the parts composing each rib are to haveflanges cast upon each of the ends which abut against theconnecting or tie plates, and are to be secured to themcy 3 inch square threaded wrought iron screw-pins in eachflange. Each flange is to be clipped, and made true over the'''hole of its surface to the exact radius of the arch, so as tocave a solid and true joint. The ends of the parts of ther ‘fls which are to be fixed in the sockets of the springing-Plates are to be clipped, and made true over their whole sur-*ace of section, so that they may have a sound, solid, andabutting joint. The parts of each tie or connectingplate against which each part of the rib abuts, must, for the'''hole area of each flange, be made to the exact radius ofhe arch, and be clipped and made to have a true and evena ce. Joggles are also to be cast upon each tie or connectingPlate, which are to fit into the joggles cast on the ends of theParts of the ribs. Both the male joggles upon the tie orc pnnecting plates, and the female joggles at the ends of the•bs, are to be made to the radius of the arch, and clipped,j'bfl made true over their whole surface, so that each jointa 7 be solid and true throughout.

‘ Upon the top of each of the ribs is to be a shouldering,tinning its whole length, having sockets to receive the■1 Sgles upon the bottom of the spandrils. Diagonal braces ofa t-iron, of the same section, form, and dimension, and dis-j^ Se d in the manner as represented in the drawings, are to“ Se d ; each of the parts composing the braces are to abutu °ainst the ribs in the situations and in the manner shown0 **° n the drawings, and secured to them by keys and cotters,Wedges, filed, and made true upon their edges ; the parts ofof 6 / Jraces which abut against the ribs, and also the facet | ( l b e snugs or bed-pieces, cast upon the ribs to receivesob!?’- mus t be chipped so that they may have a true“A Joint.

as s P aT] drils are to be of the same form and dimensionsare t ' 0Wn u PO n the drawing. The spandrils over each ribout ’a ^ le sa J ne i n every respect, excepting that upon ther Onn' ^ ace ol ^ t * le ou tside spandrils a fillet must be cast,fi][ et ' n £ found each opening, as shown upon the drawing; thethe 1 l ° i llc fl wide, and projecting f of an inch upon

be 0tto ® °f the spandrils; at the point of each lozenge mustE ar g as , t jeggles to fit into sockets on the tops of the ribs.JOffal 3 80 t0 ca8t at t * ie same pl ace > the situations of theinte r eS a . n< l ears marked upon the drawings. At the centralquite S6Ctl0n eac fl lozenge there must be a brace runningthe d acr ? ss the bridge ; each must be done as shown uponin < j;„ awin g s > viz., having a wrought-iron screw bolt inchpi ates t^ter, passing through cast-iron tubes, with washer,Placed'' °Vquite across the bridge. These braces are to bespdfldrj 1 ] 11 ” ,e ^nations as marked upon the drawings. Thefleeted h * )e ca8t * n an y convenient lengths, and con-gou ger ^ fl an ges of proper strength, and 14 inch wrought-

CW-pi ns>

“ The outside Spandrils are also to have a flange cast ontheir tops, running the whole length of the bridge, to bedthe cornice, &c., upon.

“ The cornice is to be of the same form and dimension asshown upon the drawing, having strengthening pieces castinside, not farther asunder than 3 feet. It must be cast inlengths not exceeding 9 feet; and each piece is to be con-nected to the other by internal flanges and three 1£ inchwrought-iron screw-pins in each joint. The bottom of thecornice will lie upon a flange cast upon the top of the outsidespandrils, and be secured to it, and the road-plates 1-J inchwrought-iron screw-pins, two in each road-plate.

“ The plinth is to be of the dimensions and form as shownupon the drawings ; it must be cast in lengths not exceeding8 feet 6 inches, each piece to be connected to the other by adove-tailed joint. Ears are also to be cast on the bottom ofeach side, to secure it to the top of the cornice by 1^ inchwrought-iron screw-pins, not more than two feet asunder.Sockets are to be cast in the top of the plinth, to receive.

“ The palisade bars are to be 1J inch square, placed arris-ways, and not more than 6 inches asunder from centre tocentre. The handrail is to be of the same dimensions andform as shown upon the drawings, having sockets cast on theunder sides to receive the tops of the palisade bars ; and it isto be screwed to the top of every sixth palisade bar, with acounter-sunk headed screw, and it must be secured or con-nected with the pedestals in the manner shown upon thedrawings. The pedestals are to be of the same dimensionand form as shown upon the drawings, having sunk panelson the front and back ; internal flanges to be cast on the topto receive the handrail, and the caps are to be put on withcounter-sunk headed screws. Brackets are also to be cast oneach side of every sixth palisade bar, of the same form asshown upon the drawings, and secured by screw-pins to theplinth.

“ The covering or road-plates are to be reticulated, and ofthe same dimension and form as shown upon the drawing,having flanges cast on their under sides to receive the bearersor tops of the spandrils ; they are to be secured to the top ofthe centre spandrils, and to the flanges cast on the top of theoutside spandrils, by 1-J- inch wrought-iron screw-pins, twoin each joint. They are also to be connected to each otherby flanges cast on their under sides, and two 1J inch wrought-iron screw-pins in each joint.

“ None of the castings are to be run from the blast-furnace,but the whole work must be made from good No. 2 pig-iron,of a quality satisfactory to the surveyor or surveyors of theworks of the county of Stafford. All the screw-pins, nuts,washers, keys, cotters, wedges, &c., are to be made of thebest malleable iron. All the joints are to be made in a goodworkmanlike manner; and the whole of the work must befitted and fixed at the contractor’s works, and inspected bythe county surveyor previous to its being sent off. All thework must be moulded, wrought, fitted, end erected, in asubstantial and workmanlike manner, and to the entire satis-faction of the county surveyor or surveyors.

“ The contractor must find and pay for all patterns, materials,tools, cement, tackling for fixing his work, and all otherutensils or requisite things connected with the constructionand fixing his part of the work. The estimates are to begiven in a gross sum, and must include carriage of all mate-rials to, and fixing the work at, the place of the intendederection.

“ The county of Stafford will be at the expense of the wholeof the masonry of the abutments, and cutting and letting inthe iron-work into the masonry, and will also provide cen-tering for turning the arch.