FOUNDATIONS. 



some light upon the ultimate resistance of brick masonry 

 under normal and actual conditions. 



Below the ground-surface, with a bearing-soil of good, stiff 

 clay, four piers of 6 ft. base and 2 ft. square tops, construc- 

 ted of sound, hard-burned Georgia clay, laid in a mortar con- 

 sisting of I part Belgian cement and 2 parts sharp road-sand, 

 and into each of which two anchor-rods ij ins. diameter with 

 12 X f-in. boiler-plate washers had been inserted, had been 

 constructed for the support of a 13-ft. diameter by 2 5 -ft. 

 high steel water-tank, supported by a four-column tower, 

 40 ft. in height. Upon the detail drawings a 24 X 24-in. 

 cap was shown-, but owing to a misunderstanding as to who 

 was to furnish this bearing-plate, the cap was not provided. 

 A delay in securing the necessary anchor-rods from the 

 manufacturer resulted in the purchase by the assistant en- 

 gineer of a set of ij-in., 5-ft. rods, supplied with the 12 ins. 

 square boiler-plate washers. Later, when the original rods 

 were received, accompanying them was a set of 12 X i8-in. 

 washers, which, through the carelessness and ignorance of 

 the assistant engineer and the erecting foreman, were set on 

 top of the foundations to serve as bearing-plates for the 

 tower. The piers were completed exactly 45 days before 

 the final test, at which time the tank was filled within 2 feet 

 of its top, when the foundations gave way and the whole 

 structure failed. 



The weight of the material was 28,000 Ibs., the weight of 

 the water at 62 \ Ibs. per cu. ft. was 192,000 Ibs., the approxi- 

 mate weight of each pier was 9,000 Ibs. At the time of the 

 failure there was no wind blowing, so that the total weight 

 applied as compression was 256,000 Ibs., or 128.0 tons. With 

 the 24 X 24-in. cap specified, the bearing upon the masonry 

 would have been 8 tons per square foot. 



Under the conditions at the initial moment of failure, the 

 entire weight of the tank and load, amounting to 1 10 tons, 



