SPECIFICATIONS FOE STEEL HIGHWAY BRIDGES. 5 
Structural material delivered at the bridge shop ^2. jtor^age of 
receiving yard shall be stored above the surface of the 
ground upon platforms, skids or other supports and shall 
be protected as far as practicable from surface deteriora- 
tion by exposure to conditions producing rust. It shall 
be kept free from acciunulations of dirt, oil, or other 
foreign matter. 
Fabricated material stored prior to shipment shall be 
subject to the same conditions of storage as the unfab- 
ricated material in the shop receiving yard. 
All deformed structural material shall be properly. 3. straighten- 
straight ened by methods which are noninjurious prior ^°^ ™^ ^"^^^ ' 
to being laid off, punched, or otherwise worked in the 
shop. Sharp Idnks and bends shall be cause for rejection. 
The workmanship and finish shall be first class andg^^tp^d^^Sh.^" 
equal to the best practice in modern bridge shops. 
Shearing and chipping shall be neatly and accurately 
done and all portions of the work exposed to view shall 
be neatly finished. 
No changes shall be made in any drawing after it ^as g^^^g^^^ha^g^s and 
been approved except by the consent or direction of the * , 
engineer in writing. 
Substitutions of sections having different dimensions 
than those shown on the plans shall be made only when 
approved in writing by the engineer. 
EIVET HOLES. 
When general reaming is not required, holes in ma- 6. Rivet holes. 
terial % inch or less in thickness may be punched full 
size. Holes in material more than % inch in thickness 
shall be subpunched and reamed, or drilled from the 
solid. 
Full-sized j)unched holes shall be -^q inch larger than 7. Punched 
the nominal diameter of the rivet. The diameter of the^°^^^' 
die shall not exceed the diameter of the punch by more 
than -^ inch. Holes must be clean cut, without torn 
or ragged edges. If any holes must be enlarged to admit 
the rivets, they shall be reamed. 
The punching of holes shall be so accurately done that, s. Accuracy of 
after assembling the component parts of a member, ^^ p^^^^^^^ ^^^^^s. 
cylindrical pin ^ inch smaller than the nominal diameter 
of the punched hole may be passed through at least 75 
of any group of 100 contiguous holes in the same surface 
or in like proportion for any group of holes. If this 
requirement is not fulfilled the badly punched pieces 
shall be rejected. If any holes will not pass a pin ^ 
inch smaller than the nominal diameter 01 the punched 
hole, this shall be cause for rejection. 
Drilled holes shall be xg inch larger than the nominal 9- d r 1 1 1 e d 
diameter of the rivet. Burrs on the outside surfaces 
shaU be removed with a tool producing a i^-inch fillet 
around the edge of the hole. 
