386 STEEL STAND-PIPES AND ELEVATED TANKS ON TOWERS. CHAP. XI. 



29. The diameter of the die used in punching rivet holes shall not exceed that of the punch 

 by more than ^ in. All rivet holes shall be punched, except as stated in Part I, Section 19. 



30. All punched and reamed bolts shall be clean cuts, without torn or ragged edges. The 

 burrs on all reamed holes shall be removed by a tool, countersinking not more than ^ in. Any 

 parts of the structure in which difficulties may arise in field riveting, shall be assembled in the 

 shop and marked properly before shipment. 



31. Rivet holes shall be accurately spaced; eccentrically located rivet holes, if not sufficient 

 to cause rejection shall be corrected by reaming, and rivets of larger size shall be used in the 

 holes thus reamed. 



32. The use of drift-pins will be allowed only for bringing together several parts forming 

 part of the structure; force will not be allowed to be used in drifting under any circumstances. 



33. The use of sledges in driving or hammering any part of the structure will not be allowed. 

 Care shall be taken to prevent material from falling, or from being in any way subjected to heavy 

 shocks. 



34. Rivets shall be driven by pressure tools wherever possible. Pneumatic hammers shall 

 be used in preference to hand-driving. All rivet heads shall be concentric with the holes. 



35. All caulking shall be done with a round-nosed tool, and only by experienced and skilled 

 men. Caulking around rivet heads will not be allowed. All leaky rivets shall be cut out and 

 replaced with new ones. All fractured material shall be replaced free of cost to the owner. 



36. If the owner furnishes an inspector, he shall have full access, at all times to all parts of 

 the shop where material under his inspection is being manufactured. 



37. The inspector shall stamp with a private mark each piece accepted. Any piece not thus 

 marked may be rejected at any time, and at any stage of the work. If the inspector, through 

 oversight or otherwise, has accepted material or work which is defective or contrary to these 

 specifications, this material, no matter in what stage of completion, may be rejected by the owner. 



Painting and Testing. 38. Before leaving the shop, all steel work excepting the laps in 

 contact on the tank work, shall receive one coat of approved paint or boiled linseed oil. All 

 parts which will be inaccessible after erection shall be well painted, except as stated before. 



39. After the structure is erected and all seams have been caulked, it shall be tested for 

 water-tightness, and leaky places shall be caulked or marked. The water shall then be dis- 

 charged and the leaky seams shall be caulked. Leaky rivets shall be treated as per Section 35. 

 After the structure has been standing empty for 3 days it shall be retested, and then, if all joints 

 are water-tight, it shall be given one coat of approved paint both inside and outside of the tank or 

 stand-pipe. Painting in the open air shall never be done in wet or freezing weather. The owner 

 will select the color of the final coat of paint. 



40. The contractor shall guarantee the tightness of the tank, or stand-pipe, against leakage, 

 when filled with the liquid it is designed to contain. 



PART IV. FOUNDATIONS FOR ELEVATED TANKS ON TOWERS, AND FOR STAND-PIPES. 



1. The average permissible pressure on the soil is as follows: 



Soft clay I ton per sq. ft. 



Ordinary clay 2 tons per sq. ft. 



Dry sand and dry clay 3 tons per sq. ft. 



Hard clay 4 tons per sq. ft. 



Gravel and coarse sand 6 tons per sq. ft. 



2. In all cases a thorough investigation of the ground and the site shall be made before 

 proceeding with the foundations. 



3. All foundations shall be carried below the frost line, and the anchor-bolts shall be placed 

 deep enough to develop their full strength. ' 



4. In foundations for towers with inclined legs supporting elevated tanks care shall be taken 

 that the piers are constructed in such a manner, that the resultant of the vertical and horizontal 

 forces, due to direct loads, passes through the center of gravity of the piers. 



5. Foundations, in general, shall be of concrete composed of I part Portland cement, 3 parts 

 sand, and 5 parts crushed stone or gravel. In special cases, where part of the foundation is 

 under water, the concrete shall be a I : 2 : 4 mixture. 



Note. For specifications for mixing and placing the concrete in the foundations, see Chap- 

 ter V. 



