Engineering and Contracting . 2. The bottomparts of the ends of the slabs are reinforced Construction.—Each slab was cast in place oivthe piers in a single piede, and is held in posi-tion by dowels set into the piers, except atexpansion joints. The 1-in. space betweenthe slabs was filled with tarred paper. In theforeground of Fig. 3 there is shown some ofthe contractors equipment for handling ma-terials and for spouting the concrete for theslabs. The forms for several slabs and thesteel truss supports for them are shown inplace. In the background can be seen derricks February 11, 1914. Enginee
Engineering and Contracting . 2. The bottomparts of the ends of the slabs are reinforced Construction.—Each slab was cast in place oivthe piers in a single piede, and is held in posi-tion by dowels set into the piers, except atexpansion joints. The 1-in. space betweenthe slabs was filled with tarred paper. In theforeground of Fig. 3 there is shown some ofthe contractors equipment for handling ma-terials and for spouting the concrete for theslabs. The forms for several slabs and thesteel truss supports for them are shown inplace. In the background can be seen derricks February 11, 1914. Engineering and Contracting 197 and a hoisting and spouting tower, which arebeing used to construct the piers. B.\SCLLE SPAN. Figure 4 shows an elevation of the basculespan and adjacent spans, the type of structure sists of built-up floorbeams and stringerssupporting the ties. The fixed span, whichcarries the operating machinery, has a troughfloor, except along the center of the spanwhere there is a 2-in. board walk, 2 ft. 10 Fig. 3. View Showing Gunpowder River BridShown in Place in Foreground; Pie used for the bascule span, and the molhod ofoperation being indicated by the drawing. Theclear opening of this span is 35 ft., as thegirder swings into a vertical position. It isoperated by hand through a rack and chain ofgears. Mechanism is provided for raisingthe ends of the lift span and for freeing itfrom the operating machinery when the spanis closed. The counterweight consists of a steel in concrete. This box is filled with acomposition consisting of concrete and weight of this counterweight is ^42 cubic foot, being made up of the followingproportions: 30 per cent steel at 480 lbs. ^144 lbs. per cubic foot; and 70 per cent con-crete at 140 lbs. = 98 lbs. per cubic foot. The floor construction for the lift span con- ge During Construction; Formwork for Slabsrs Being Constructed in Background. wide. The trough floor is filled with con-crete, upon w
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