1 8 TOWERS AND TANKS FOR WATER-WORKS. 



Eye-witnesses state that there was a sudden burst of water 

 from the tank, followed by its immediate collapse. When the 

 tank reached the ground its conical bottom was almost wholly 

 separated into three parts. The cylindrical portion of the tank 

 was intact around the whole lower ring and showed no signs 

 of failure, except for a few openings in some of the upper joints 

 caused by the shock of falling. The bottom portion of six or 

 seven of the supporting posts fell upon the top of the tank, as did 

 also the two lower lengths, or 40 feet in all, of the lo-in. wrought- 

 iron feed-pipe. The girder and parts which supported the tank 

 were tossed and bent and buried underneath the tank. The 

 foundations, except for the displacement of two or three of the 

 capstones, were unimpaired. 



Wherever the bottom and the sides parted in the wreck, with 

 but few exceptions it was the rivets that failed. An examination 

 of the whole circumference of the angle iron attached to the 

 lower edge of the sides of the tank showed only three stretches, 

 ij, ij, and 8 feet respectively, where the flange of the bottom 

 plates had ruptured and was still attached to the angle which 

 united the sides and bottom of the tank. 



From investigation it was found that three- fourths of the 

 failure was due to rivets and but one- fourth to ruptured plate 

 of the bottom. 



The flanged part of the bottom plate was weakened by the 

 counter- sinking for the rivets, yet where the flanged plate tore, 

 the rupture was along the line of the rivet -holes for only two 

 stretches of six rivets each. The rivets, so far as they remained 

 in evidence, failed in their lower or counter-sunk heads; most 

 of these heads pulled right through the bottom plate, the edges 

 of the counter-sunk heads pulling over the end. None could 

 be found which had sheared off. From the original design of 

 this tank, departure was as follows: (i) Substitution of steel for 

 wrought iron in tank and tension members of tower. (2) The 

 flanr/rd bottom of tank was riveted to the angle only, instead 



